Photocatalytic water splitting by semiconductors is a promising technology to produce clean H_(2) fuel,but the efficiency is restrained seriously by the high overpotential of the H_(2)-evolution reaction together with...Photocatalytic water splitting by semiconductors is a promising technology to produce clean H_(2) fuel,but the efficiency is restrained seriously by the high overpotential of the H_(2)-evolution reaction together with the high recombination rate of photoinduced charges.To enhance H_(2) production,it is highly desirable yet challenging to explore an efficient reductive cocatalyst and place it precisely on the right sites of the photocatalyst surface to work the proton reduction reaction exclusively.Herein,the metalloid NixP cocatalyst is exactly positioned on the Z-scheme Cd_(0.5)Zn_(0.5)S/NiTiO_(3)(CZS/NTO)heterostructure through a facile photodeposition strategy,which renders the cocatalyst form solely at the electron-collecting locations.It is revealed that the directional transfer of photoexcited electrons from Cd_(0.5)Zn_(0.5)S to Ni_(x)P suppresses the quenching of charge carriers.Under visible light,the CZS/NTO hybrid loaded with the Ni_(x)P cocatalyst exhibits an optimal H_(2) yield rate of 1103μmol h^(-1)(i.e.,27.57 mmol h^(-1)g^(-1)),which is about twofold of pristine CZS/NTO and comparable to the counterpart deposited with the Pt cocatalyst.Besides,the high apparent quantum yield(AQY)of 56%is reached at 400 nm.Further,the mechanisms of the cocatalyst formation and the H2 generation reaction are discussed in detail.展开更多
Metal-free g-C_3N_4 is widely used in photocatalytic reactions owing to its suitable band structure.However, it has low specific surface area and insufficient absorbance for visible light, and its photoexcited carrier...Metal-free g-C_3N_4 is widely used in photocatalytic reactions owing to its suitable band structure.However, it has low specific surface area and insufficient absorbance for visible light, and its photoexcited carriers have high recombination rates. In this study, the 3 D macropore C-vacancy g-C_3N_4 was prepared through a facile one-step route. Polymethylmethacrylate is used as a template to increase the surface reaction sites of g-C_3N_4 and extend its visible-light range. Compared to unmodified g-C_3N_4, the H2 production and CO_2 reduction rates of the fabricated g-C_3N_4 significantly improved. The special pore structure significantly improved the light utilization efficiency of g-C_3N_4 and increased the number of surface-active sites. The introduction of C-vacancy extended the absorption band of visible-light and suppressed the carrier recombination. The newly developed synthesis strategy can improve solar energy conversion efficiency and potentially modifies g-C_3N_4.展开更多
Photocatalytic water splitting on noble metal-free photocatalysts for H_(2) generation is a promising but challenging approach to realize solar-to-chemical energy conversion.In this study,Mo/Mo_(2)C nanoparticles anch...Photocatalytic water splitting on noble metal-free photocatalysts for H_(2) generation is a promising but challenging approach to realize solar-to-chemical energy conversion.In this study,Mo/Mo_(2)C nanoparticles anchored carbon layer(Mo/Mo_(2)C@C)was obtained by a one-step in-situ phase transition approach and developed for the first time as a photothermal cocatalyst to enhance the activity of ZnIn_(2)S_(4)photocatalyst.Mo/Mo_(2)C@C nanosheet exhibits strong absorption in the full spectrum region and excellent photo-thermal conversion ability,which generates heat to improve the reaction temperature and accelerate the reaction kinetics.Moreover,metallic Mo/Mo_(2)C@C couples with ZnIn_(2)S_(4)to form ZnIn_(2)S_(4)-Mo/Mo_(2)C@C Schottky junction(denoted as ZMM),which prevents the electrons back transfer and restrains the charge recombination.In addition,conductive carbon with strong interfacial interaction serves as a fast charge transport bridge.Consequently,the optimized ZMM-0.2 junction exhibits an H2 evolution rate of 1031.07μmol g^(-1)h^-(1),which is 41 and 4.3 times higher than bare ZnIn_(2)S_(4)and ZnIn_(2)S_(4)-Mo2C,respectively.By designing novel photothermal cocatalysts,our work will provide a new guidance for designing efficient photocatalysts.展开更多
Engineering lattice defects in two-dimensional(2 D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion.Although many researches have proven the...Engineering lattice defects in two-dimensional(2 D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion.Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn_(2)S_(4),the artificial control of Sdefects for optimizing the charge-carrier kinetics process in ZnIn_(2)S_(4) has long been a challenging task.Herein,we report a facile one-step method to modulate the lattice S-content of ZnIn_(2)S_(4) microflowers(MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1:2.We also demonstrated that the Svacancies at the In facets were the main type of lattice defects in the formed ZnIn_(2)S_(4) MFs,which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels(DELs) and the reduced effective mass of electrons,as evidenced by the first-principles calculations and the electron spectra analyses.The ZnIn_(2)S_(4) MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron(~94.64 ns) for contributing to the photo-physical and-chemical processes.Thus,upon visible light irradiation,the H_(2)-evolution rate of this sample reached ~2.40 mmol h^(-1) g^(-1) with an apparent quantum efficiency of ~0.16% at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts.展开更多
Hydrogen acquisition from solar energy is an effective way to address energy crisis,which makes the development of efficient photocatalysts become the main direction of scientific research.Herein,cobalt phthalocyanine...Hydrogen acquisition from solar energy is an effective way to address energy crisis,which makes the development of efficient photocatalysts become the main direction of scientific research.Herein,cobalt phthalocyanine/oxygen-doped g-C_(3)N_(4)(CoPc/OCN) S-scheme heterojunction photocatalyst was designed by coupling multi-step calcination with solvothermal method for enhanced photothermal-assisted photocatalytic H_(2) evolution.The multistep calcined g-C_(3)N_(4) is easier for O-doping formation,and the ethanol solvothermal strategy is utilized to enhance the dispersion of CoPc on OCN nano sheet surface and forms sufficient S-scheme heterojunction through H-bonds.In addition,the active sites and excellent photothermal properties of CoPc itself further improve the integrated photocatalytic activity of CoPc/OCN S-scheme heterojunction.The optimal photocatalytic hydrogen evolution rate of CoPc/OCN S-scheme heterojunction photocatalyst reached 9.56 mmol·g^(-1)·h^(-1),which is 2.69 and 1.23 times higher than that of CN and OCN,respectively.This work provides a valuable design idea and scheme for enhancing the multi-factor co-assisted photocatalytic H_(2) evolution performance.展开更多
Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion process.In this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybri...Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion process.In this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybrids were successfully constructed via combining Ni_(2)P-NiS with T-MCS solid solution for visible light photocatalytic H_(2)evolution.T-MCS is composed of zinc blende Mn_(0.5)Cd_(0.5)S(ZB-MCS)and wurtzite Mn_(0.5)Cd_(0.5)S(WZ-MCS)and those two alternatively arranged crystal phases endow T-MCS with excellent bulk phase charge separation performance for the slight energy level difference between ZB-MCS and WZ-MCS.S-scheme carriers transfer route between NiS and T-MCS can accelerate the interfacial charge separation and retain the active electrons and holes,meanwhile,co-catalyst Ni_(2)P as electron receiver and proton reduction center can further optimize the H_(2)evolution reaction kinetics based on the surface Schottky barrier effect.The above-formed homo-heterojunctions can establish multiple charge transfer channels in the bulk phase of T-MCS and interface of T-MCS and Ni_(2)P-NiS.Under the synergistic effect of twinned homojunction,S-scheme heterojunction,and Schottky barrier,the ternary Ni_(2)P-NiS/T-MCS com-posite manifested an H_(2)production rate of 122.5 mmol h^(-1)g^(-1),which was 1.33,1.24,and 2.58 times higher than those of the NiS/T-MCS(92.4 mmol h^(-1)g^(-1)),Ni_(2)P/T-MCS(98.4 mmol h^(-1)g^(-1)),and T-MCS(47.5 mmol h^(-1)g^(-1)),respectively.This work demonstrates a promising strategy to develop efficient sul-fides photocatalyst toward targeted solar-driven H_(2)evolution through homo-heterojunction engineering.展开更多
Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was...Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was synthesized through employing defective Ti0_(2) nanosheets as solid support for photo-catalytic water splitting.It indicated that the surface oxygen vacancies on defective Ti0_(2) nanosheets could effectively stabilize the single-atomic Pt sites through constructing a three-center Ti-Pt-Ti structure.The Ti-Pt-Ti structure can hold the stability of isolated single-atomic Pt sites and facilitate the separation and transfer of photoinduced charge carriers,thereby greatly improving the photocatalytic H2 evolution.Notably,our synthesized photocatalyst exhibited a remarkably enhanced H2 evolution performance,and the H2 production rate is up to 13460.7μmol h^(-1)·g^(-1),which is up to around 29.0 and 4.7 times higher than those of Ti0_(2) nanosheets and Pt nanoparticles-Ti0_(2).In addition,a plausible enhanced reaction mechanism was also proposed combining with photo-electrochemical characterizations and density functional theoiy(DFT)calculation results.Ultimately,it is believed that this work highlights the benefits of a single-site catalyst and paves the way to rationally design the highly active and stable single-atomic site photocatalysts on metal oxide support.展开更多
Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Non...Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Nonetheless,the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation.Herein,we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets(iCONs)by tailoring the functional group via molecular engineering.Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride(TG)and aldehyde linkers.The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties,and thus reduced the dielectric confinement and the corresponding exciton binding energy(E_(b)).The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation.This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts.展开更多
Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density fun...Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density functional theory,hall effect,and in situ diffuse reflectance infrared Fourier transform spec-troscopy,it is revealed that photo-irradiated e^(−)and h^(+)can be spatially separated and directionally trans-ferred to the reductive high-index facet{002}and oxidative low-index facet{110}of localized CdS homo-junction induced by Fermi level difference of both high and low index facets to dehydrogenate∗-OH and coupled∗-O intermediates for H_(2)and O_(2)yield,respectively,along with a solar conversion into hydrogen of 1.93%by AM 1.5 G irradiation at 65℃.The study work suggests a scientific perspective on the optimal ratio of high and low index facets to understand photo-generated charge carrier transfer dynamically and their photocatalytic principle for H_(2)O splitting reaction in kinetics.展开更多
Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution performance.Herein,a unique one-dimensional(1D)/two-dimensi...Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution performance.Herein,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was designed.The introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution reaction.Furthermore,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of charges.As a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) samples.Based on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is proposed.This work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.展开更多
A highly efficient piezocatalyst of oxygen-incorporated Mo S_(2)(O-Mo S_(2)) was designed and successfully synthesized via facile modulation of hydrothermal process temperature method.Remarkably,a superior piezocataly...A highly efficient piezocatalyst of oxygen-incorporated Mo S_(2)(O-Mo S_(2)) was designed and successfully synthesized via facile modulation of hydrothermal process temperature method.Remarkably,a superior piezocatalytic H_(2) evolution rate of 46.1μmol·g^(-1)·h^(-1)in pure water and921.0μmol·g^(-1)·h^(-1)in methanol solution is obtained on optimal O-MoS_(2)-180 (with a hydrothermal process temperature of 180℃),outperforming pristine Mo S_(2)and most of the reported other catalysts.Moreover,piezocatalytic activity of O-MoS_(2) toward the degradation of organic pollutants depends on hydrothermal temperatures.The suitable temperature of O-Mo S_(2)-180 presents dramatically excellent piezocatalytic capacity compared with the pristine MoS_(2) for degradation of methylene blue (MB) dye.The reaction rate constant of O-Mo S_(2)-180 reaches to 54.6×10^(-3)min^(-1),which is nearly 18 and 4-folds in contrast with pristine MoS_(2) and O-Mo S_(2)-140 (with a hydrothermal process temperature of 140℃),respectively.Simultaneously,it also manifests that O-MoS_(2)-180 endows relatively high degradation efficiency (84.6%within30 min) and excellent stability.Moreover,it is also demonstrated that optimal O-MoS_(2) can dramatically promote charge carriers transport and separation.Furthermore,our theoretical calculation results suggest that the oxygenincorporated can modulate the surface electronic state,enhance active sites as well as optimize the hydrogen adsorption Gibbs free energy of MoS_(2),thus extremely boosting piezocatalytic efficiency.Ultimately,an innovative piezocatalytic mechanism is proposed to reveal and expound the relationship between piezocatalytic property and oxygen-incorporated role.展开更多
As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a...As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.展开更多
Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the s...Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis.展开更多
Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Ins...Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Inspired by the spatially separated architecture,a chloroplast-like structured photocatalyst(PdS@CdS@MoS_(2)),in which the PdS and MoS_(2) function as enzymes in the chloroplast and CdS shell functions as the chloroplast envelope,was developed to improve the photocatalytic H_(2) evolution.In this unique nanoscale bionic structure,the poriferous CdS shell enhances light absorption,generates photoinduced carriers,and separates oxidation and reduction reactions.Meanwhile,PdS and MoS_(2) dual cocatalysts enhance the charge separation efficiency through forming a built-in electric field with CdS.We demonstrate that the separation efficiency of carriers,carrier lifetime,and the yield of H_(2) are both higher than that of CdS nanoparticles,evidencing the feasibility of the chloroplast-like structure in enhancing the photocatalyst activity.This work emphasizes the synergism of the three key processes of the photocatalytic reaction by simulating the chloroplast structure and provides a general synthesis strategy,the synthesis of novel structured for photocatalysts for diverse applications in the energy field.展开更多
C_(3)N_(4),C_(3)N_(4)@Ti_(3)C_(2)and W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres were successfully prepared by using SiO_(2)template followed by gradual deposition method.The degradation of phenol solution and p...C_(3)N_(4),C_(3)N_(4)@Ti_(3)C_(2)and W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres were successfully prepared by using SiO_(2)template followed by gradual deposition method.The degradation of phenol solution and photolysis ability were tested to characterize its photocatalytic activity.Compared with the single-shelled C_(3)N_(4)and C_(3)N_(4)@Ti_(3)C_(2)hollow spheres,double-shelled W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres possessed larger surface area and fast charge separation efficiency,exhibiting about 8.9 times and 4.0 times higher H_(2)evolution than those of C_(3)N_(4),C_(3)N_(4)@Ti_(3)C_(2)hollow spheres,respectively.The photocatalytic mechanism of the W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres were carefully investigated according to the results of morphology design and photoelectric performance.A Z scheme mechanism based on the construction of heterojunctions was proposed to explain the improvement of photocatalytic performance.This new charge transfer mechanism appears to greatly inhibit the recombination of electrons/holes during the charge transfer process,while maintaining its strong hydrogen reduction ability,resulting in a higher photocatalytic performance.展开更多
Biodegradable magnesium alloys are promising candidates for temporary fracture fixation devices in orthopedics;nevertheless,its fast degradation rate at the initial stage after implantation remains as one of the main ...Biodegradable magnesium alloys are promising candidates for temporary fracture fixation devices in orthopedics;nevertheless,its fast degradation rate at the initial stage after implantation remains as one of the main challenges to be resolved.ZrO_(2)-based coatings to reduce the degradation rate of the Mg-implants are an attractive solution since they show high biocompatibility and stability.In this work,the degradation,cytotoxicity,and antibacterial performance of ZrO_(2)thin films deposited by magnetron sputtering on a Mg-Zn-Ca alloy was evaluated.Short-term degradation of ZrO_(2)-coated and uncoated samples was assessed considering electrochemical techniques and H_(2)evolution(gas chromatography).Additionally,long term degradation was assessed by mass-loss measurements.The results showed that a 380 nm ZrO_(2)coating reduces the degradation rate and H_(2)evolution of the alloy during the initial 3 days after immersion but allows the degradation of the bare alloy for the long-term.The ZrO_(2)coating does not compromise the biocompatibility of the alloy and permits better cell adhesion and proliferation of mesenchymal stem cells directly on its surface,in comparison to the bare alloy.Finally,the ZrO_(2)coating prevents the adhesion and biofilm formation of S.aureus.展开更多
Intimate understanding of the synthesis-structure-activity relationships is an accessible pathway to overcome the intrinsic challenges of carbon nitride(g-C_(3)N_(4))photocatalysts.This work looks in the effects of hu...Intimate understanding of the synthesis-structure-activity relationships is an accessible pathway to overcome the intrinsic challenges of carbon nitride(g-C_(3)N_(4))photocatalysts.This work looks in the effects of humidity of the synthesis process to the morphology,chemical structure,band structure as well as the photocatalytic activity of g-C_(3)N_(4) materials.Four g-C_(3)N_(4) samples were prepared by heating melem in four gas environments:dry Ar,dry Air,moist Ar and moist Air.The photocatalytic activity measurements revealed that the samples synthesized in moist inert and oxidic gases environments displayed 20 and 10 times the photocata lytic H_(2) evolution activity of the samples synthesized in dry inert and oxidic gases environments,respectively.The reasons for this remarkable variety in photocata lytic activities had been through investigated.After all,the terminations of the carbon vacancies were identified as the dominant factor in enhancing H_(2) evolution performance.The work here thus demonstrating an example of defect engineering.展开更多
The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isoty...The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.展开更多
Because of its importance in enhancing charge separation and transfer,built-in electric field engineering has been acknowledged as an effective technique for improving photocatalytic performance.Herein,a stable p–n h...Because of its importance in enhancing charge separation and transfer,built-in electric field engineering has been acknowledged as an effective technique for improving photocatalytic performance.Herein,a stable p–n heterojunction of 2D/2D(2D:twodimensional)Co_(3)O_(4)/ZnIn_(2)S_(4)with a strong built-in electric field is precisely constructed.The Co_(3)O_(4)/ZnIn_(2)S_(4)heterojunction exhibits a higher visible-light photocatalytic hydrogen(H2)evolution rate than the individual components,which is primarily attributed to the synergy effect of improved light absorption,abundant active sites,short charge transport distance,high separation efficiency of photogenerated carriers.Furthermore,the photoelectrochemical studies and density functional theory(DFT)calculation results demonstrate that the enhanced interfacial charge separation and migration induced by the generated built-in electric field are the critical reasons for the boosted photocatalytic performance.This research might pave the way for the rational design and manufacturing of 2D/2D heterojunction photocatalysts with extremely efficient photocatalytic performance for solar energy conversion.展开更多
As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attenti...As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attentions.Herein,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing process.The gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within it.This special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface reaction.Thus,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube array.With the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications.展开更多
基金supported by the National Key R&D Program of China(2021YFA1502100 and 2022YFE0114800)the National Natural Science Foundation of China(22372035,22302039 and 22311540011).
文摘Photocatalytic water splitting by semiconductors is a promising technology to produce clean H_(2) fuel,but the efficiency is restrained seriously by the high overpotential of the H_(2)-evolution reaction together with the high recombination rate of photoinduced charges.To enhance H_(2) production,it is highly desirable yet challenging to explore an efficient reductive cocatalyst and place it precisely on the right sites of the photocatalyst surface to work the proton reduction reaction exclusively.Herein,the metalloid NixP cocatalyst is exactly positioned on the Z-scheme Cd_(0.5)Zn_(0.5)S/NiTiO_(3)(CZS/NTO)heterostructure through a facile photodeposition strategy,which renders the cocatalyst form solely at the electron-collecting locations.It is revealed that the directional transfer of photoexcited electrons from Cd_(0.5)Zn_(0.5)S to Ni_(x)P suppresses the quenching of charge carriers.Under visible light,the CZS/NTO hybrid loaded with the Ni_(x)P cocatalyst exhibits an optimal H_(2) yield rate of 1103μmol h^(-1)(i.e.,27.57 mmol h^(-1)g^(-1)),which is about twofold of pristine CZS/NTO and comparable to the counterpart deposited with the Pt cocatalyst.Besides,the high apparent quantum yield(AQY)of 56%is reached at 400 nm.Further,the mechanisms of the cocatalyst formation and the H2 generation reaction are discussed in detail.
基金financial support from the National Natural Science Foundation of China (51862023, 51662030, 21868016)the Natural Science Foundation of Jiangxi Province (20171BAB206014, 2018BCD40004)。
文摘Metal-free g-C_3N_4 is widely used in photocatalytic reactions owing to its suitable band structure.However, it has low specific surface area and insufficient absorbance for visible light, and its photoexcited carriers have high recombination rates. In this study, the 3 D macropore C-vacancy g-C_3N_4 was prepared through a facile one-step route. Polymethylmethacrylate is used as a template to increase the surface reaction sites of g-C_3N_4 and extend its visible-light range. Compared to unmodified g-C_3N_4, the H2 production and CO_2 reduction rates of the fabricated g-C_3N_4 significantly improved. The special pore structure significantly improved the light utilization efficiency of g-C_3N_4 and increased the number of surface-active sites. The introduction of C-vacancy extended the absorption band of visible-light and suppressed the carrier recombination. The newly developed synthesis strategy can improve solar energy conversion efficiency and potentially modifies g-C_3N_4.
基金supported by National Natural Science Foundation of China(Nos.21971143 and 21805165)the Hubei Provincial Department of Education(D20201207)and 111 Project(D20015).
文摘Photocatalytic water splitting on noble metal-free photocatalysts for H_(2) generation is a promising but challenging approach to realize solar-to-chemical energy conversion.In this study,Mo/Mo_(2)C nanoparticles anchored carbon layer(Mo/Mo_(2)C@C)was obtained by a one-step in-situ phase transition approach and developed for the first time as a photothermal cocatalyst to enhance the activity of ZnIn_(2)S_(4)photocatalyst.Mo/Mo_(2)C@C nanosheet exhibits strong absorption in the full spectrum region and excellent photo-thermal conversion ability,which generates heat to improve the reaction temperature and accelerate the reaction kinetics.Moreover,metallic Mo/Mo_(2)C@C couples with ZnIn_(2)S_(4)to form ZnIn_(2)S_(4)-Mo/Mo_(2)C@C Schottky junction(denoted as ZMM),which prevents the electrons back transfer and restrains the charge recombination.In addition,conductive carbon with strong interfacial interaction serves as a fast charge transport bridge.Consequently,the optimized ZMM-0.2 junction exhibits an H2 evolution rate of 1031.07μmol g^(-1)h^-(1),which is 41 and 4.3 times higher than bare ZnIn_(2)S_(4)and ZnIn_(2)S_(4)-Mo2C,respectively.By designing novel photothermal cocatalysts,our work will provide a new guidance for designing efficient photocatalysts.
基金supported by the National Natural Science Foundation of China(Grant Nos.51772041,12074055,62005036)the LiaoNing Revitalization Talents Program(XLYC1807176)+2 种基金the Natural Science Foundation of Liaoning Province(Grant No.2020-MZLH-15)the Dalian Science Foundation for Distinguished Young Scholars(2018RJ05)the support from the Liaoning BaiQianWan Talents Program。
文摘Engineering lattice defects in two-dimensional(2 D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion.Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn_(2)S_(4),the artificial control of Sdefects for optimizing the charge-carrier kinetics process in ZnIn_(2)S_(4) has long been a challenging task.Herein,we report a facile one-step method to modulate the lattice S-content of ZnIn_(2)S_(4) microflowers(MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1:2.We also demonstrated that the Svacancies at the In facets were the main type of lattice defects in the formed ZnIn_(2)S_(4) MFs,which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels(DELs) and the reduced effective mass of electrons,as evidenced by the first-principles calculations and the electron spectra analyses.The ZnIn_(2)S_(4) MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron(~94.64 ns) for contributing to the photo-physical and-chemical processes.Thus,upon visible light irradiation,the H_(2)-evolution rate of this sample reached ~2.40 mmol h^(-1) g^(-1) with an apparent quantum efficiency of ~0.16% at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts.
基金financially supported by the National Natural Science Foundation of China (Nos.21906072, 21906039, 21908115 and 22006057)Hebei Province 333 Talents Project (No.A202101020)+3 种基金the Science and Technology Project of Hebei Education Department (No.BJ2021010)the Graduate Student Innovation Ability Training Funding Project of Hebei Province (No.CXZZSS2023129)the Open Fund for Hebei Province Key Laboratory of Sustained Utilization & Development of Water Recourse (No.HSZYL2022002)Instrumental Analysis Center, Jiangsu University of Science and Technology。
文摘Hydrogen acquisition from solar energy is an effective way to address energy crisis,which makes the development of efficient photocatalysts become the main direction of scientific research.Herein,cobalt phthalocyanine/oxygen-doped g-C_(3)N_(4)(CoPc/OCN) S-scheme heterojunction photocatalyst was designed by coupling multi-step calcination with solvothermal method for enhanced photothermal-assisted photocatalytic H_(2) evolution.The multistep calcined g-C_(3)N_(4) is easier for O-doping formation,and the ethanol solvothermal strategy is utilized to enhance the dispersion of CoPc on OCN nano sheet surface and forms sufficient S-scheme heterojunction through H-bonds.In addition,the active sites and excellent photothermal properties of CoPc itself further improve the integrated photocatalytic activity of CoPc/OCN S-scheme heterojunction.The optimal photocatalytic hydrogen evolution rate of CoPc/OCN S-scheme heterojunction photocatalyst reached 9.56 mmol·g^(-1)·h^(-1),which is 2.69 and 1.23 times higher than that of CN and OCN,respectively.This work provides a valuable design idea and scheme for enhancing the multi-factor co-assisted photocatalytic H_(2) evolution performance.
基金supported by the National Natu-ral Science Foundation of China(Nos.22078261,21676213,and 11974276)Natural Science Basic Research Program of Shaanxi(No.2023-JC-YB-115)+1 种基金Shaanxi Key Science and Technology Innovation Team Project(No.2022TD-33)National College Student Inno-vation and Entrepreneurship Training Program(No.202210697069)for the financial support of this work.
文摘Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion process.In this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybrids were successfully constructed via combining Ni_(2)P-NiS with T-MCS solid solution for visible light photocatalytic H_(2)evolution.T-MCS is composed of zinc blende Mn_(0.5)Cd_(0.5)S(ZB-MCS)and wurtzite Mn_(0.5)Cd_(0.5)S(WZ-MCS)and those two alternatively arranged crystal phases endow T-MCS with excellent bulk phase charge separation performance for the slight energy level difference between ZB-MCS and WZ-MCS.S-scheme carriers transfer route between NiS and T-MCS can accelerate the interfacial charge separation and retain the active electrons and holes,meanwhile,co-catalyst Ni_(2)P as electron receiver and proton reduction center can further optimize the H_(2)evolution reaction kinetics based on the surface Schottky barrier effect.The above-formed homo-heterojunctions can establish multiple charge transfer channels in the bulk phase of T-MCS and interface of T-MCS and Ni_(2)P-NiS.Under the synergistic effect of twinned homojunction,S-scheme heterojunction,and Schottky barrier,the ternary Ni_(2)P-NiS/T-MCS com-posite manifested an H_(2)production rate of 122.5 mmol h^(-1)g^(-1),which was 1.33,1.24,and 2.58 times higher than those of the NiS/T-MCS(92.4 mmol h^(-1)g^(-1)),Ni_(2)P/T-MCS(98.4 mmol h^(-1)g^(-1)),and T-MCS(47.5 mmol h^(-1)g^(-1)),respectively.This work demonstrates a promising strategy to develop efficient sul-fides photocatalyst toward targeted solar-driven H_(2)evolution through homo-heterojunction engineering.
基金This research was funded by the Canadian Centre for Clean Coal/Carbon and Mineral Processing Technologies(C5MPT),the National Key R&D Program of China(2017YFB0310803)and the China Scholarship Council(CSC).We thank the NanoFAB at the University of Alberta for the convenience of instruments use,and the kindly help of Nanqi Duan and Chao Qi on sample characterization.
文摘Single-atomic site catalysts have drawn considerable attention because of their maximum atom-utilization efficiency and excellent catalytic activity.In this work,a highly active single-atomic Pt site photocatalyst was synthesized through employing defective Ti0_(2) nanosheets as solid support for photo-catalytic water splitting.It indicated that the surface oxygen vacancies on defective Ti0_(2) nanosheets could effectively stabilize the single-atomic Pt sites through constructing a three-center Ti-Pt-Ti structure.The Ti-Pt-Ti structure can hold the stability of isolated single-atomic Pt sites and facilitate the separation and transfer of photoinduced charge carriers,thereby greatly improving the photocatalytic H2 evolution.Notably,our synthesized photocatalyst exhibited a remarkably enhanced H2 evolution performance,and the H2 production rate is up to 13460.7μmol h^(-1)·g^(-1),which is up to around 29.0 and 4.7 times higher than those of Ti0_(2) nanosheets and Pt nanoparticles-Ti0_(2).In addition,a plausible enhanced reaction mechanism was also proposed combining with photo-electrochemical characterizations and density functional theoiy(DFT)calculation results.Ultimately,it is believed that this work highlights the benefits of a single-site catalyst and paves the way to rationally design the highly active and stable single-atomic site photocatalysts on metal oxide support.
基金the National Natural Science Foundation of China(22072065,22178162,22222806)the Distinguished Youth Foundation of Jiangsu Province(BK20220053)the Six Talent Peaks Project in Jiangsu Province(JNHB-035)。
文摘Ultra-thin two-dimensional(2D)organic semiconductors are promising candidates for photocatalysts because of the short charge diffusion pathway and favorable exposure of active sites plus the versatile architecture.Nonetheless,the inherent dielectric confinement of 2D materials will induce a strong exciton effect hampering the charge separation.Herein,we demonstrated an effective way to reduce the dielectric confinement effect of 2D ionic covalent organic nanosheets(iCONs)by tailoring the functional group via molecular engineering.Three ultra-thin CONs with different functional groups and the same ionic moieties were synthesized through Schiff base condensation between ionic amino monomer triaminoguanidinium chloride(TG)and aldehyde linkers.The integration of the hydroxyl group was found to significantly increase the dielectric constant by enhancing the polarizability of ionic moieties,and thus reduced the dielectric confinement and the corresponding exciton binding energy(E_(b)).The champion hydroxyl-functional iCON exhibited promoted exciton dissociation and in turn a high photocatalytic hydrogen production rate under visible-light irradiation.This work provided insights into the rationalization of the dielectric confinement effect of low-dimensional photocatalysts.
基金supported by the National Natural Science Foundation of China(No.51972177)the Natural Science Foundation of Ningbo City(No.2021J067)the SJLY2021010 of Ningbo University,Fan 3315 Plan,and Yongjiang Scholar Project.
文摘Localized CdS homojunctions with optimal ratio of high and low index facets are constructed to dy-namically boost H_(2)O splitting into H_(2)energy by hydrothermal method in combination with calcination.By density functional theory,hall effect,and in situ diffuse reflectance infrared Fourier transform spec-troscopy,it is revealed that photo-irradiated e^(−)and h^(+)can be spatially separated and directionally trans-ferred to the reductive high-index facet{002}and oxidative low-index facet{110}of localized CdS homo-junction induced by Fermi level difference of both high and low index facets to dehydrogenate∗-OH and coupled∗-O intermediates for H_(2)and O_(2)yield,respectively,along with a solar conversion into hydrogen of 1.93%by AM 1.5 G irradiation at 65℃.The study work suggests a scientific perspective on the optimal ratio of high and low index facets to understand photo-generated charge carrier transfer dynamically and their photocatalytic principle for H_(2)O splitting reaction in kinetics.
基金This study was financially supported by the National Natural Science Foundation of China(Nos.12075174 and 91963207)the National Key Research and Development Program of China(No.2022YFA1602701).
文摘Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution performance.Herein,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was designed.The introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution reaction.Furthermore,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of charges.As a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) samples.Based on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is proposed.This work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.
基金financially supported by the Talent Program of Tianshan Youth of Xinjiang Autonomous Region (No. 2020Q070)the National Natural Science Foundation of China (No. 12064042)。
文摘A highly efficient piezocatalyst of oxygen-incorporated Mo S_(2)(O-Mo S_(2)) was designed and successfully synthesized via facile modulation of hydrothermal process temperature method.Remarkably,a superior piezocatalytic H_(2) evolution rate of 46.1μmol·g^(-1)·h^(-1)in pure water and921.0μmol·g^(-1)·h^(-1)in methanol solution is obtained on optimal O-MoS_(2)-180 (with a hydrothermal process temperature of 180℃),outperforming pristine Mo S_(2)and most of the reported other catalysts.Moreover,piezocatalytic activity of O-MoS_(2) toward the degradation of organic pollutants depends on hydrothermal temperatures.The suitable temperature of O-Mo S_(2)-180 presents dramatically excellent piezocatalytic capacity compared with the pristine MoS_(2) for degradation of methylene blue (MB) dye.The reaction rate constant of O-Mo S_(2)-180 reaches to 54.6×10^(-3)min^(-1),which is nearly 18 and 4-folds in contrast with pristine MoS_(2) and O-Mo S_(2)-140 (with a hydrothermal process temperature of 140℃),respectively.Simultaneously,it also manifests that O-MoS_(2)-180 endows relatively high degradation efficiency (84.6%within30 min) and excellent stability.Moreover,it is also demonstrated that optimal O-MoS_(2) can dramatically promote charge carriers transport and separation.Furthermore,our theoretical calculation results suggest that the oxygenincorporated can modulate the surface electronic state,enhance active sites as well as optimize the hydrogen adsorption Gibbs free energy of MoS_(2),thus extremely boosting piezocatalytic efficiency.Ultimately,an innovative piezocatalytic mechanism is proposed to reveal and expound the relationship between piezocatalytic property and oxygen-incorporated role.
基金fundings from the National Natural Science Foundation of China(No.51872173)Taishan Scholars Program of Shandong Province(No.tsqn201812068)+1 种基金Natural Science Foundation of Shandong Province(No.ZR2022JQ21)Higher School Youth Innovation Team of Shandong Province(No.2019KJA013).
文摘As one of the 2D transition metal sulfides,1T phase MoS_(2) nanosheets(NSs)have been studied because of their distinguished conductivity and suitable electronic structure.Nevertheless,the active sites are limited to a small number of edge sites only,while the basal plane is catalytically inert.Herein,we report that boron(B)doped 1T phase MoS_(2) NSs can replace precious metals as a co-catalyst to assist in photocatalytic H_(2) production of 2D layered g-C_(3)N_(4) nanosheets(g-C_(3)N_(4) NSs).The H_(2) evolution rate of prepared B-MoS_(2)@g-C_(3)N_(4) composites with 15 wt%B-MoS_(2)(B-MoS_(2)@g-C_(3)N_(4)–15,1612.75μmol h^(−1) g^(−1))is 52.33 times of pure g-C_(3)N_(4) NSs(30.82μmol h^(−1) g^(−1)).Furthermore,the apparent quantum efficiency(AQE)of B-MoS_(2)@g-C_(3)N_(4)–15 composites under the light atλ=370 nm is calculated and reaches 5.54%.The excellent photocatalytic performance of B-MoS_(2)@g-C_(3)N_(4)–15 composites is attributed to the B ions doping inducing the distortion of 1T phase MoS_(2) crystal,which can activate more base planes to offer more active sites for H_(2) evolution reaction(HER).This work of B-MoS_(2)@g-C_(3)N_(4) composites offers experience in the progress of effective and low-price photocatalysts for HER.
基金the National Natural Science Foundation of China(No.22002142)China Postdoctoral Science Foundation(No.2020T130605)+2 种基金Natural Science Foundation of Henan Province(No.202300410436)Support Plan for College Science and Technology Innovation Team of Henan Province(No.16IRTSTHN001)the Science&Technology Innovation Talent Plan of Henan Province(No.174200510018).
文摘Incorporating metal nanodots(NDs)into heterostructures for high charge separation and transfer capacities is one of the most effective strategies for improving their photocatalytic activities.However,controlling the space distribution of metal NDs for optimizing charge transport pathways remains a significant challenge,particularly in two-dimensional(2D)face-to-face heterostructures.Herein,we develop a simple targeted self-reduction strategy for selectively loading Ru NDs onto the Ti_(3−x)C_(2)T_(y)(TC)surface of 2D TC/g-C_(3)N_(4)(CN)heterojunction based on the reductive Ti vacancy defects creatively increased during the preparation of TC/CN by reducing calcination.Notably,the optimized Ru/TC/CN photocatalyst exhibits an outstanding H_(2)evolution rate of 3.21 mmol·g^(−1)·h^(−1)and a high apparent quantum efficiency of 30.9%at 380 nm,which is contributed by the unidirectional transfer of the photogenerated electrons from CN to Ru active sites(CN→TC→Ru)and the suppressed backflow of electrons from Ru sites to CN,as revealed by comprehensive characterizations and density functional theory(DFT)calculations.This work provides a novel strategy for synthesizing the highly efficient photocatalysts with a controllable charge transfer paths,which will boost the development of photocatalysis.
基金supported by the Gansu Provincial Development and Reform Commission(NDRC,No.2013-1336).
文摘Photosynthesis with the chloroplast works efficiently because of the envelope structure that serves to carry enzymes and to simultaneously maintain the spatial separation of photosynthesis and cellular respiration.Inspired by the spatially separated architecture,a chloroplast-like structured photocatalyst(PdS@CdS@MoS_(2)),in which the PdS and MoS_(2) function as enzymes in the chloroplast and CdS shell functions as the chloroplast envelope,was developed to improve the photocatalytic H_(2) evolution.In this unique nanoscale bionic structure,the poriferous CdS shell enhances light absorption,generates photoinduced carriers,and separates oxidation and reduction reactions.Meanwhile,PdS and MoS_(2) dual cocatalysts enhance the charge separation efficiency through forming a built-in electric field with CdS.We demonstrate that the separation efficiency of carriers,carrier lifetime,and the yield of H_(2) are both higher than that of CdS nanoparticles,evidencing the feasibility of the chloroplast-like structure in enhancing the photocatalyst activity.This work emphasizes the synergism of the three key processes of the photocatalytic reaction by simulating the chloroplast structure and provides a general synthesis strategy,the synthesis of novel structured for photocatalysts for diverse applications in the energy field.
基金Supported by the National Natural Science Foundation of China(Nos.91963207 and 12075174)。
文摘C_(3)N_(4),C_(3)N_(4)@Ti_(3)C_(2)and W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres were successfully prepared by using SiO_(2)template followed by gradual deposition method.The degradation of phenol solution and photolysis ability were tested to characterize its photocatalytic activity.Compared with the single-shelled C_(3)N_(4)and C_(3)N_(4)@Ti_(3)C_(2)hollow spheres,double-shelled W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres possessed larger surface area and fast charge separation efficiency,exhibiting about 8.9 times and 4.0 times higher H_(2)evolution than those of C_(3)N_(4),C_(3)N_(4)@Ti_(3)C_(2)hollow spheres,respectively.The photocatalytic mechanism of the W_(18)O_(49)@C_(3)N_(4)@Ti_(3)C_(2)hollow spheres were carefully investigated according to the results of morphology design and photoelectric performance.A Z scheme mechanism based on the construction of heterojunctions was proposed to explain the improvement of photocatalytic performance.This new charge transfer mechanism appears to greatly inhibit the recombination of electrons/holes during the charge transfer process,while maintaining its strong hydrogen reduction ability,resulting in a higher photocatalytic performance.
基金supported by CONACYT-Frontera-1740,CONACy T-CB-288101,CONACy T-299703,and DGAPAPAPIIT-IN101419 projectssupport from the CONACYT Ph.D.-scholarship(CVU 606030)+2 种基金the program Doctorado en Ciencia e Ingeniería de Materials at the Universidad Nacional Autónoma de Méxicothe support from the program Maestría y Doctorado en Ciencias Médicas,Odontológicas y de la Salud at the Universidad Nacional Autónoma de México and the Ph.D.scholarship from CONACy T(CVU 856985)the support from the program Posgrado de Doctorado en Ciencias en Biomedicina y Biotecnología Molecular,Escuela Nacional de Ciencias Biológicas at the Instituto Politécnico Nacional and the Ph.D.scholarship from CONACy T(CVU 739515)
文摘Biodegradable magnesium alloys are promising candidates for temporary fracture fixation devices in orthopedics;nevertheless,its fast degradation rate at the initial stage after implantation remains as one of the main challenges to be resolved.ZrO_(2)-based coatings to reduce the degradation rate of the Mg-implants are an attractive solution since they show high biocompatibility and stability.In this work,the degradation,cytotoxicity,and antibacterial performance of ZrO_(2)thin films deposited by magnetron sputtering on a Mg-Zn-Ca alloy was evaluated.Short-term degradation of ZrO_(2)-coated and uncoated samples was assessed considering electrochemical techniques and H_(2)evolution(gas chromatography).Additionally,long term degradation was assessed by mass-loss measurements.The results showed that a 380 nm ZrO_(2)coating reduces the degradation rate and H_(2)evolution of the alloy during the initial 3 days after immersion but allows the degradation of the bare alloy for the long-term.The ZrO_(2)coating does not compromise the biocompatibility of the alloy and permits better cell adhesion and proliferation of mesenchymal stem cells directly on its surface,in comparison to the bare alloy.Finally,the ZrO_(2)coating prevents the adhesion and biofilm formation of S.aureus.
基金financially supported by the National Natural Science Foundation of China(No.21777063,21676128)The Natural Science Foundation of Jiangsu Province(BK20180887)+1 种基金a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions,High-tech Research Key Laboratory of Zhenjiang(SS2018002)The High Performance Computing Platform of Jiangsu University。
文摘Intimate understanding of the synthesis-structure-activity relationships is an accessible pathway to overcome the intrinsic challenges of carbon nitride(g-C_(3)N_(4))photocatalysts.This work looks in the effects of humidity of the synthesis process to the morphology,chemical structure,band structure as well as the photocatalytic activity of g-C_(3)N_(4) materials.Four g-C_(3)N_(4) samples were prepared by heating melem in four gas environments:dry Ar,dry Air,moist Ar and moist Air.The photocatalytic activity measurements revealed that the samples synthesized in moist inert and oxidic gases environments displayed 20 and 10 times the photocata lytic H_(2) evolution activity of the samples synthesized in dry inert and oxidic gases environments,respectively.The reasons for this remarkable variety in photocata lytic activities had been through investigated.After all,the terminations of the carbon vacancies were identified as the dominant factor in enhancing H_(2) evolution performance.The work here thus demonstrating an example of defect engineering.
基金supported by the National Natural Science Foundation of China (Nos.62004143 and 21975084)the Central Government Guided Local Science and Technology Development Special Fund Project (No.2020ZYYD033)+5 种基金the Natural Science Foundation of Hubei Province (No.2021CFB133)the Opening Fund of Key Laboratory of Rare Mineral,Ministry of Natural Resources(No.KLRM-KF 202005)the Opening Fund of Key Laboratory for Green Chemical Process of Ministry of Education of Wuhan Institute of Technology (No.GCP202101)the Open Research Fund of Key Laboratory of Material Chemistry for Energy Conversion and Storage (HUST),Ministry of Education (No.2021JYBKF05)the Innovation Project of Engineering Research Center of Phosphorus Resources Development and Utilization of Ministry of Education (No.LCX2021003)the 12^(th) Graduate Education Innovation Fund of Wuhan Institute of Technology (No.CX2020341)。
文摘The rational fabrication of an efficient heterojunction is critical to the enhancement of photocatalytic hydrogen(H_(2)) evolution performance.Herein,a new-fashioned graphitic-carbon nitride(g-C_(3) N_(4)) based isotype step-scheme(S-scheme) heterojunction composed of sulfur-doped and sulfur-free active sites is developed by liquid sulfur-mediation of exfoliated g-C_(3) N_(4).Particularly,the liquid sulfur not only contributes to the full contact between sulfur species and exfoliated g-C_(3) N_(4),but also creates sulfur-doping and abundant pores,since self-gas foaming effect of sulfur vapor.Moreover,the S-doped and S-free active sites located in the structural unit of C_(3) N_(4) jointly construct a typical sulfur-doped g-C_(3) N_(4)/g-C_(3) N_(4) isotype step-scheme heterojunction,which endows highly efficient photocatalytic reaction process.Therefore,the optimal sample possesses remarkable photocatalytic H_(2) evolution activity(5548.1 μmol g^(-1) h^(-1)) and robust durability.Most importantly,the investigation will open up a new path for the exploration of other carbon-based isotype S-scheme heterojunctions.
基金the National Key R&D Program of China(No.2020YFC1808401)the National Natural Science Foundation of China(Nos.22078213,21938006,51973148,and 21776190)+2 种基金cutting-edge technology basic research project of Jiangsu(No.BK20202012)the project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).G.P.Z.is also grateful for support from the Project funded by China Postdoctoral Science Foundation(No.2021M702389)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB536).
文摘Because of its importance in enhancing charge separation and transfer,built-in electric field engineering has been acknowledged as an effective technique for improving photocatalytic performance.Herein,a stable p–n heterojunction of 2D/2D(2D:twodimensional)Co_(3)O_(4)/ZnIn_(2)S_(4)with a strong built-in electric field is precisely constructed.The Co_(3)O_(4)/ZnIn_(2)S_(4)heterojunction exhibits a higher visible-light photocatalytic hydrogen(H2)evolution rate than the individual components,which is primarily attributed to the synergy effect of improved light absorption,abundant active sites,short charge transport distance,high separation efficiency of photogenerated carriers.Furthermore,the photoelectrochemical studies and density functional theory(DFT)calculation results demonstrate that the enhanced interfacial charge separation and migration induced by the generated built-in electric field are the critical reasons for the boosted photocatalytic performance.This research might pave the way for the rational design and manufacturing of 2D/2D heterojunction photocatalysts with extremely efficient photocatalytic performance for solar energy conversion.
基金support is gratefully acknowledged from the National Natural Science Foundation of China(NSFC)(Nos.62004137,21878257,and 21978196)the Natural Science Foundation(NSF)of Shanxi Province(No.20210302123102)+4 种基金the Key Research and Development Program of Shanxi Province(No.201803D421079)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0156)the Research Project Supported by Shanxi Scholarship Council of China(No.2020-050)the Fundamental Research Funds for the Central Universities(No.2682021CX116)Sichuan Science and Technology Program(No.2020YJ0259).
文摘As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attentions.Herein,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing process.The gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within it.This special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface reaction.Thus,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube array.With the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications.
