Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the...Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.展开更多
Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the n...Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.展开更多
A novel carboxylated lactose/sodium lignosulfonate/polyacrylic acid hydrogel composites with self-reduction capacity was successfully synthesized by self-assembly method.The hydrogel with well-developed porous structu...A novel carboxylated lactose/sodium lignosulfonate/polyacrylic acid hydrogel composites with self-reduction capacity was successfully synthesized by self-assembly method.The hydrogel with well-developed porous structure provided abundant anchoring points and reduction capacity for transforming Ag^(+)into silver nanoparticles.Silver nanoparticles dispersed among the network of hydrogel and the composites exhibited catalytic capacity.The catalytic performance was evaluated via degradation of p-nitrophenol,rhodamine B,methyl orange and methylene blue,which were catalyzed with corresponding reaction rate constants of 0.04338,0.07499,0.04891,and 0.00628 s^(–1),respectively.In addition,the catalyst exhibited stable performance under fixed-bed condition and the corresponding conversion rate still maintained more than 80%after 540 min.Moreover,the catalytic performance still maintained effective in tap water and simulated seawater.The catalytic efficiency still remained 99.7%with no significant decrease after 8 cycles.展开更多
In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,...In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.展开更多
MXene, a new type of two-dimensional layered transition metal carbide material differing from graphene, demonstrates intriguing chemical/physical properties and wide applications in recent years. Here, the preparation...MXene, a new type of two-dimensional layered transition metal carbide material differing from graphene, demonstrates intriguing chemical/physical properties and wide applications in recent years. Here, the preparation of the self-assembled MXene-gold nanoparticles （MXene@AuNPs） nanocomposites with tunable sizes is reported. The nano- composites are obtained via the self-reduction reactions of MXene material in a HAuCI4 solution at room temperature. The sizes of the Au particles can be well-controlled by reg- ulating the self-reduction reaction time. They can greatly in- fluence the catalytic behaviors of the MXene@AuNPs composites. MXene@AuNPs composites with optimized re- duction time show high catalytic performances and good cycle stability for model catalytic reactions of nRro-compounds, such as 2-nitrophenol and 4-nitrophenol. This work demon- strates a new approach for the preparation of tunable MXene- based self-assembled composites.展开更多
The self-reduction experiment of manganese-rich slag briquette containing carbon was carried out in a high- temperature carbon tube furnace. The main factors affecting the reduction rate were analyzed, and the kinetic...The self-reduction experiment of manganese-rich slag briquette containing carbon was carried out in a high- temperature carbon tube furnace. The main factors affecting the reduction rate were analyzed, and the kinetic model of reduction was established. The results show that the increase of basicity of briquette has an obvious effect on im- proving reduction rate. When the carbon ratio of briquettes is 1.2 and its basicity is 1.0, the reduction rate can reach 90 %. It can accelerate reduction process and decrease reduction time when the appropriate flux CaF2 is added to the briquette. The apparent activation energy of chemical reaction is 24.07 kJ/mol, and the apparent activation energy of internal diffusion is 107.55 kJ/mol by calculation. Therefore, the reduction rate of briquette is determined by the mass transfer of CO in the product layer.展开更多
Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant challenges.Developing new materials and innovative stru...Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant challenges.Developing new materials and innovative structural design concepts is crucial for expanding the application field of electromagnetic wave absorption.Particularly,hierarchical structure engineering has emerged as a promising approach to enhance the physical and chemical properties of materials,providing immense potential for creating versatile electromagnetic wave absorption materials.Herein,an exceptional multi-dimensional hierarchical structure was meticulously devised,unleashing the full microwave attenuation capabilities through in situ growth,selfreduction,and multi-heterogeneous interface integration.The hierarchical structure features a three-dimensional carbon framework,where magnetic nanoparticles grow in situ on the carbon skeleton,creating a necklace-like structure.Furthermore,magnetic nanosheets assemble within this framework.Enhanced impedance matching was achieved by precisely adjusting component proportions,and intelligent integration of diverse interfaces bolstered dielectric polarization.The obtain Fe_(3)O_(4)-Fe nanoparticles/carbon nanofibers/Al-Fe_(3)O_(4)-Fe nanosheets composites demonstrated outstanding performance with a minimum reflection loss(RLmin)value of−59.3 dB and an effective absorption bandwidth(RL≤−10 dB)extending up to 5.6 GHz at 2.2 mm.These notable accomplishments offer fresh insights into the precision design of high-efficient electromagnetic wave absorption materials.展开更多
With the strict control of sulfur content in fuels,oxidative desulfurization(ODS),a promising desulphurization technology,needs to be continuously developed.In this study,we integrated multiple approaches(fabricating ...With the strict control of sulfur content in fuels,oxidative desulfurization(ODS),a promising desulphurization technology,needs to be continuously developed.In this study,we integrated multiple approaches(fabricating a porous structure,increasing phosphomolybdic acid(PMo)loading,improving amphiphilicity,and enhancing the intrinsic activity of PMo using a reductive framework)into PAF-54 carriers to improve ODS catalytic ability.The catalytic performance suggested that PAF-54 was not simply used as a carrier for PMo by physical integration.During the binding process,electron transfer between PAF-54 and PMo formed Mo^(5+)with superior catalytic activity.Owing to the presence of PAF-54,the catalytic activity of PMo as the active component qualitatively improved to achieve rapid and efficient desulfurization.More importantly,we found that other nitrogen-rich porous organic polymers can also reduce some of Mo^(6+)in PMo during loading,and its formation mechanism was investigated.This work provides a feasible strategy for designing highly efficient DOS catalysts.展开更多
Integrating active Pt clusters into transition-metal oxides with water-dissociation ability is effective to prepare a bifunctional electrocatalyst for water splitting in alkaline.However,the additional utilization of ...Integrating active Pt clusters into transition-metal oxides with water-dissociation ability is effective to prepare a bifunctional electrocatalyst for water splitting in alkaline.However,the additional utilization of a reductant and/or the operation at the elevating temperature causes the over-growth and agglomeration of Pt clusters,thus losing the high catalytic performance.Herein,we report that V dopant not only favors self-reducing Pt clusters on Ni Fe layered double hydroxide(LDH)(Pt/NiFeV)at room temperature,but also regulates interfacial charge redistribution to enhance the water-splitting performance.Experimental and theoretical studies reveal that V dopant into Ni Fe LDH triggers more electrons to transfer to adjacent Fe atoms,thus leading to a higher reducing ability compared to that without V-doping.When used as water-splitting electrocatalyst,V doping promotes electron loss of Pt clusters in Pt/Ni Fe V,optimizing the free energy of hydrogen adsorption and proton recombination kinetics at the cathode.Meanwhile,it also moves the d-band center of Ni away from the Fermi level to optimize the adsorption of*OH intermediates and facilitate the desorption of oxygen molecules at the anode.Thereby,Pt/Ni Fe V exhibits much higher bifunctional performance than V-free Pt/Ni Fe LDH toward both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).This work can spark inspiration of designing other bifunctional electrocatalysts for energy conversion and storage.展开更多
Using high temperature carbon tube furnace, reduction of manganese ore pellets containing carbon was investigated. The reaction was divided into two stages at five minutes after reaction, and the kinetics model of red...Using high temperature carbon tube furnace, reduction of manganese ore pellets containing carbon was investigated. The reaction was divided into two stages at five minutes after reaction, and the kinetics model of reduction process was established. The experimental results showed that, the reaction rate in the earlier stage was controlled by the chemical reactions between FeO, MnO and carbon reductant, and the activation energy was 28.85 KJ/mol. In the later stage, as the carbon reductant replaced by CO, the reaction rate was controlled by CO-diffusing in solid products, and the cor- responding activation energy was 86.56 KJ/mol. Reaction rate of the later stage was less than the earlier one.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
In this work,gold nanoparticles(AuNPs)decorated Ti_(3)C_(2)T_(x) nanosheets(MXene/AuNPs composite)are fabricated through a self-reduction reaction of Ti_(3)C_(2)T_(x) nanosheets with HAuCl_(4) aqueous solution.The obt...In this work,gold nanoparticles(AuNPs)decorated Ti_(3)C_(2)T_(x) nanosheets(MXene/AuNPs composite)are fabricated through a self-reduction reaction of Ti_(3)C_(2)T_(x) nanosheets with HAuCl_(4) aqueous solution.The obtained composite is characterized as AuNPs with the diameter of about 23 nm uniformly dispersing on nanosheets without aggregation.The composite(MXene decorated on 4.8 wt% AuNPs)is further employed to construct supercapacitor for the first time with a higher specific capacitance of 278 F·g^(-1) at 5 mV·s^(-1) than that of pure Ti_(3)C_(2)T_(x) and 95% of cyclic stability after 10,000 cycles.Furthermore,MXene/AuNPs composite symmetric supercapacitor with filter paper as separator and H_(2)SO_(4) as electrolyte,is assembled.The supercapacitor exhibits a high volumetric energy density of 8.82 Wh·L^(-1) at a power density of 264.6 W·L^(-1) and ultrafast-charging/discharging performance.It exhibits as a promising candidate applied in integrated and flexible supercapacitors.展开更多
The problem of water pollution has become increasingly serious,and it has already threatened the survival of mankind and has become an obstacle to the healthy development of human health.Here,we prepared a novel polyv...The problem of water pollution has become increasingly serious,and it has already threatened the survival of mankind and has become an obstacle to the healthy development of human health.Here,we prepared a novel polyvinyl alcohol(PVA)/polyacrylic acid(PAA)/MXene fiber membrane by electrospinning.After heat treatment of film and subsequent modification with Pd nanoparticles,PVA/PAA/MXene@PdNPs composite nanofiber membrane with high specific surface area and excellent catalytic performance was finally prepared.The uniform distribution of MXene sheets in the composite fiber membrane not only solves the problem that the MXene sheet is not easy to be monolayerized,but also can grow the self-reduced Pd nanoparticles on the MXene sheets.In addition,the composite nanofiber membrane exhibits excellent catalytic ability and cycle stability for 4-nitrophenol(4-NP)and 2-nitrophenol(2-NA),providing new strategy for the study of catalytic composite materials related to degradation of wastewater.展开更多
A novel hyperbranched multiarm copolymer of HBPO-star-PDEAEMA with a hydrophobic poly(3-ethyl-3-(hydroxymethyl) oxetane)(HBPO) core and many cationic poly(2-(N,N-diethylamino) ethyl methacrylate)(PDEAEMA) arms has bee...A novel hyperbranched multiarm copolymer of HBPO-star-PDEAEMA with a hydrophobic poly(3-ethyl-3-(hydroxymethyl) oxetane)(HBPO) core and many cationic poly(2-(N,N-diethylamino) ethyl methacrylate)(PDEAEMA) arms has been synthesized through an atom transfer radical polymerization(ATRP) method,and been applied to spontaneously reduce and stabilize gold nanoparticles(AuNPs) in water without other additional agents.The size of the nanoparticles could be effectively controlled at about 4 nm,and the nanoparticles are extremely stable in solution without aggregation even for one year.It was found that solution pH and the molar ratio of N/Au have certain effects on the size and stability of AuNPs.This work provides a simple method for the synthesis of uniform and highly stable AuNPs.展开更多
A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermol...A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermolurninescenee properties and afterglow proper- ties of the phosphors were characterized systematically using X-ray diffraction （XRD）, luminescence spectrophotometer, microcom- puter thermoluminescence dosimeter and single photon counter, respectively. Under 280 nm excitation, the broadband emissions of Eu2＋ ions were observed at 445 nm （blue） due to the 4f7→4f65d transition. It was demonstrated that there existed the self-reduction of the Eu3＋ to Eu2＋ ions in this special halide-phosphate matrix in air condition. The addition of Gd3＋ ions obviously enhanced the after- glow properties of the single doped Eu2＋ ions in the halide-phosphate phosphors. And the content of the fluoride anions also had sig- nificant influence on the afterglow properties. All results indicated that Srs （PO4）3 FxCI1-x：Eu2＋,Gd3＋ might be potential phosphors for long lasting phosphorescence （LLP） materials.展开更多
A series of luminescent Ba0.79Al10.9O17.14∶xEu (x=0.005-0.12) phosphors were prepared by high-temperature solid-state reaction in air atmosphere.The coexistence of Eu2+ and Eu3+ was observed and verified by photolumi...A series of luminescent Ba0.79Al10.9O17.14∶xEu (x=0.005-0.12) phosphors were prepared by high-temperature solid-state reaction in air atmosphere.The coexistence of Eu2+ and Eu3+ was observed and verified by photoluminescence (PL) and photoluminescence excitation (PLE) spectra,X-ray photoelectron spectra (XPS),and diffuse reflection spectra.The band emission peaking at 430 nm was assigned to 4F65D-4F7 transition of Eu2+,and another four emissions peaking at 589,619,655,and 704 nm were attributed to 4F-4F transitions of 5D0-7FJ(J=1,2,3,4) of Eu3+.The related mechanism of self-reduction was discussed in detail.The color of the Ba0.79Al10.9O17.14∶xEu phosphors could be shifted from blue (0.23,0.10) to red (0.42,0.27) by doping Li+ ions,and the temperature dependence properties were investigated.展开更多
基金funded by the National Key R&D Program of China (2018YFB1501504)the National Natural Science Foundation of China (Nos. 51776206 and 21878290)+1 种基金the Natural Science Foundation of Guangdong province (2017A030313073)CAS Pioneer Hundred Talents Program
文摘Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.
文摘Based on the process of coal-based self-reduction and melting separation at high temperature, it was investigated that the effect of process factors on the reduction of iron and nickel oxide, the metal yield and the nickel content in ferronickel about the laterite nickel ore, was from Philippines and contented low nickel, high iron and aluminum. The results showed that if the C/O mole ratio was not higher than 0.5 and the reduction temperature was kept as 1200°C and then increased up to 1500°C, the metal could not separate from molten slag for the A series of experiments, which were only added CaF<sub>2</sub>. However, when the C/O ratio was added up to 0.6 - 0.8, the metal could separate well from the slag, and the yields of Fe and Ni increased gradually. But the nickel content in the metal declined from 1.79% to 1.34%. When the C/O ratio increased to 1.2, and the temperature of melting products obtained at 1200°C and rose to 1550°C, the separation of metal from slag could not be realized in B group of tests, which were only added hydrated lime. However, when both of CaF<sub>2</sub> and hydrated lime were added, the metal could separate from slag in C group. In order to increase the content of nickel in the metal, it is necessary to restrain the reduction of iron oxide. When the C/O mole ratio is 0.6, the nickel content of metal could be 1.79%, which was higher than the theoretical ratio 1.65% of Ni/(Ni + Fe) of the latcritic nickel ore, but the yield of nickle was only 71.3%.
基金support from the National Natural Science Foundation of China(Grant Nos.21776026 and 22075034)Liaoning Revitalization Talents Program(Grant No.XLYC1902037)+1 种基金the Foundation of Key Laboratory of Pulp and Paper Science&Technology of Ministry of Education,Qilu University of Technology(Shandong Academy of Sciences)(Grant No.KF202114)Dalian high level talent innovation support program(Dalian Youth Science and Technology Star Project Support Program)(Grant No.2023RQ043).
文摘A novel carboxylated lactose/sodium lignosulfonate/polyacrylic acid hydrogel composites with self-reduction capacity was successfully synthesized by self-assembly method.The hydrogel with well-developed porous structure provided abundant anchoring points and reduction capacity for transforming Ag^(+)into silver nanoparticles.Silver nanoparticles dispersed among the network of hydrogel and the composites exhibited catalytic capacity.The catalytic performance was evaluated via degradation of p-nitrophenol,rhodamine B,methyl orange and methylene blue,which were catalyzed with corresponding reaction rate constants of 0.04338,0.07499,0.04891,and 0.00628 s^(–1),respectively.In addition,the catalyst exhibited stable performance under fixed-bed condition and the corresponding conversion rate still maintained more than 80%after 540 min.Moreover,the catalytic performance still maintained effective in tap water and simulated seawater.The catalytic efficiency still remained 99.7%with no significant decrease after 8 cycles.
基金Project supported by the National Natural Science Foundation of China(22003035,22073061)the Natural Science Foundation of Shaanxi Province Department of Education(21JK0587)+2 种基金the Natural Science Foundation of Shaanxi Province(2020GY-237)the Foundation of Shaanxi Xueqian Normal University(2020YBKJ70)Innovation and Entrepreneurship Training Program for College Students in Shaanxi Province(S202014390037)。
文摘In this work,through a facile method of low-temperature(only 350℃)self-reduction,1D nano-sized M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)blue phosphors with highly efficient performance can be obtained.The crystal structure,morphology and photoluminescence(PL)properties including thermal stability of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors were investigated.The M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors show broad band excitation spectra and narrow band emission spectra.The photoluminescence quantum yields(PLQY)of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)are as high as 98%and 87.2%,respectively.Furthermore,the color purities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)can reach 99.1%and 93.2%,respectively,When heated up to 150℃,the emission intensities of M_(2)B_(5)O_(9)CI:Eu^(2+)(M=Sr,Ca)phosphors can still keep 72.7%and80.0%,respectively.Finally,the above-mentioned phosphors exhibit outstanding performance when manufacturing WLEDs.
基金supported by the National Natural Science Foundation of China (21473153 and 51771162)Support Program for the Top Young Talents of Hebei Province, China Postdoctoral Science Foundation (2015M580214)the Scientific and Technological Research and Development Program of Qinhuangdao City (201701B004)
文摘MXene, a new type of two-dimensional layered transition metal carbide material differing from graphene, demonstrates intriguing chemical/physical properties and wide applications in recent years. Here, the preparation of the self-assembled MXene-gold nanoparticles （MXene@AuNPs） nanocomposites with tunable sizes is reported. The nano- composites are obtained via the self-reduction reactions of MXene material in a HAuCI4 solution at room temperature. The sizes of the Au particles can be well-controlled by reg- ulating the self-reduction reaction time. They can greatly in- fluence the catalytic behaviors of the MXene@AuNPs composites. MXene@AuNPs composites with optimized re- duction time show high catalytic performances and good cycle stability for model catalytic reactions of nRro-compounds, such as 2-nitrophenol and 4-nitrophenol. This work demon- strates a new approach for the preparation of tunable MXene- based self-assembled composites.
基金Item Sponsored by Specialized Research Fund for the Doctoral Program of Higher Education of China(20134219110004)
文摘The self-reduction experiment of manganese-rich slag briquette containing carbon was carried out in a high- temperature carbon tube furnace. The main factors affecting the reduction rate were analyzed, and the kinetic model of reduction was established. The results show that the increase of basicity of briquette has an obvious effect on im- proving reduction rate. When the carbon ratio of briquettes is 1.2 and its basicity is 1.0, the reduction rate can reach 90 %. It can accelerate reduction process and decrease reduction time when the appropriate flux CaF2 is added to the briquette. The apparent activation energy of chemical reaction is 24.07 kJ/mol, and the apparent activation energy of internal diffusion is 107.55 kJ/mol by calculation. Therefore, the reduction rate of briquette is determined by the mass transfer of CO in the product layer.
基金funded by the National Natural Science Foundation of China(No.51873004).
文摘Materials exhibiting high-performance electromagnetic wave absorption have garnered considerable scientific and technological attention,yet encounter significant challenges.Developing new materials and innovative structural design concepts is crucial for expanding the application field of electromagnetic wave absorption.Particularly,hierarchical structure engineering has emerged as a promising approach to enhance the physical and chemical properties of materials,providing immense potential for creating versatile electromagnetic wave absorption materials.Herein,an exceptional multi-dimensional hierarchical structure was meticulously devised,unleashing the full microwave attenuation capabilities through in situ growth,selfreduction,and multi-heterogeneous interface integration.The hierarchical structure features a three-dimensional carbon framework,where magnetic nanoparticles grow in situ on the carbon skeleton,creating a necklace-like structure.Furthermore,magnetic nanosheets assemble within this framework.Enhanced impedance matching was achieved by precisely adjusting component proportions,and intelligent integration of diverse interfaces bolstered dielectric polarization.The obtain Fe_(3)O_(4)-Fe nanoparticles/carbon nanofibers/Al-Fe_(3)O_(4)-Fe nanosheets composites demonstrated outstanding performance with a minimum reflection loss(RLmin)value of−59.3 dB and an effective absorption bandwidth(RL≤−10 dB)extending up to 5.6 GHz at 2.2 mm.These notable accomplishments offer fresh insights into the precision design of high-efficient electromagnetic wave absorption materials.
基金supported by Hainan Provincial Natural Science Foundation of China(220MS005)the National Key R&D Program of China(2022YFB3805902)+3 种基金the National Natural Science Foundation of China(22361017 and 22075040)the Innovation Platform for Academicians of Hainan Provincethe Specific Research Fund of the Innovation Platform for Academicians of Hainan Province(YSPTZX202321)the International Science&Technology Cooperation Program of Hainan Province(GHYF2022006)。
文摘With the strict control of sulfur content in fuels,oxidative desulfurization(ODS),a promising desulphurization technology,needs to be continuously developed.In this study,we integrated multiple approaches(fabricating a porous structure,increasing phosphomolybdic acid(PMo)loading,improving amphiphilicity,and enhancing the intrinsic activity of PMo using a reductive framework)into PAF-54 carriers to improve ODS catalytic ability.The catalytic performance suggested that PAF-54 was not simply used as a carrier for PMo by physical integration.During the binding process,electron transfer between PAF-54 and PMo formed Mo^(5+)with superior catalytic activity.Owing to the presence of PAF-54,the catalytic activity of PMo as the active component qualitatively improved to achieve rapid and efficient desulfurization.More importantly,we found that other nitrogen-rich porous organic polymers can also reduce some of Mo^(6+)in PMo during loading,and its formation mechanism was investigated.This work provides a feasible strategy for designing highly efficient DOS catalysts.
基金the financial support from the Science and Technology Commission of Shanghai Municipality(19ZR1479500)the National Natural Science Foundation of China(52072389)the Program of Shanghai Academic Research Leader(20XD1424300)for financial support。
文摘Integrating active Pt clusters into transition-metal oxides with water-dissociation ability is effective to prepare a bifunctional electrocatalyst for water splitting in alkaline.However,the additional utilization of a reductant and/or the operation at the elevating temperature causes the over-growth and agglomeration of Pt clusters,thus losing the high catalytic performance.Herein,we report that V dopant not only favors self-reducing Pt clusters on Ni Fe layered double hydroxide(LDH)(Pt/NiFeV)at room temperature,but also regulates interfacial charge redistribution to enhance the water-splitting performance.Experimental and theoretical studies reveal that V dopant into Ni Fe LDH triggers more electrons to transfer to adjacent Fe atoms,thus leading to a higher reducing ability compared to that without V-doping.When used as water-splitting electrocatalyst,V doping promotes electron loss of Pt clusters in Pt/Ni Fe V,optimizing the free energy of hydrogen adsorption and proton recombination kinetics at the cathode.Meanwhile,it also moves the d-band center of Ni away from the Fermi level to optimize the adsorption of*OH intermediates and facilitate the desorption of oxygen molecules at the anode.Thereby,Pt/Ni Fe V exhibits much higher bifunctional performance than V-free Pt/Ni Fe LDH toward both the hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).This work can spark inspiration of designing other bifunctional electrocatalysts for energy conversion and storage.
文摘Using high temperature carbon tube furnace, reduction of manganese ore pellets containing carbon was investigated. The reaction was divided into two stages at five minutes after reaction, and the kinetics model of reduction process was established. The experimental results showed that, the reaction rate in the earlier stage was controlled by the chemical reactions between FeO, MnO and carbon reductant, and the activation energy was 28.85 KJ/mol. In the later stage, as the carbon reductant replaced by CO, the reaction rate was controlled by CO-diffusing in solid products, and the cor- responding activation energy was 86.56 KJ/mol. Reaction rate of the later stage was less than the earlier one.
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 National Key R&D Program of China(2017YFA0207302)the National Natural Science Foundation of China(21890752,21731005,21573178,21773192,and 91845102)+3 种基金the Tencent Foundation through the XPLORER PRIZEChina Postdoctoral Science Foundation Project(2021T140394 and 2021M691877)the Young Scientists Fund of the National Natural Science Foundation of China(22202164).the funding from the Chemistry and Chemical Engineering Guangdong Laboratory(2211002 and 2111005)。
基金supported by the National Science Fund for Distinguished Young Scholars(No.52025041)the National Natural Science Foundation of China(Nos.51974021,51902020,and 51904021)+3 种基金the Fundamental Research Funds for the Central Universities(Nos.FRF-TP-18-045Al and FRF-TP-19-004B2Z)the National Postdoctoral Program for Innovative Talents(No.BX20180034)China Postdoctoral Science Foundation(No.2018M641192)the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials,Guangxi University(No.2021GXYSOF12).
文摘In this work,gold nanoparticles(AuNPs)decorated Ti_(3)C_(2)T_(x) nanosheets(MXene/AuNPs composite)are fabricated through a self-reduction reaction of Ti_(3)C_(2)T_(x) nanosheets with HAuCl_(4) aqueous solution.The obtained composite is characterized as AuNPs with the diameter of about 23 nm uniformly dispersing on nanosheets without aggregation.The composite(MXene decorated on 4.8 wt% AuNPs)is further employed to construct supercapacitor for the first time with a higher specific capacitance of 278 F·g^(-1) at 5 mV·s^(-1) than that of pure Ti_(3)C_(2)T_(x) and 95% of cyclic stability after 10,000 cycles.Furthermore,MXene/AuNPs composite symmetric supercapacitor with filter paper as separator and H_(2)SO_(4) as electrolyte,is assembled.The supercapacitor exhibits a high volumetric energy density of 8.82 Wh·L^(-1) at a power density of 264.6 W·L^(-1) and ultrafast-charging/discharging performance.It exhibits as a promising candidate applied in integrated and flexible supercapacitors.
基金the financial supports of the National Natural Science Foundation of China(No.21872119)Support Program for the Top Young Talents of Hebei Province+1 种基金China Postdoctoral Science Foundation(No.2015M580214)Research Program of the College Science&Technology of Hebei Province(No.ZD2018091)。
文摘The problem of water pollution has become increasingly serious,and it has already threatened the survival of mankind and has become an obstacle to the healthy development of human health.Here,we prepared a novel polyvinyl alcohol(PVA)/polyacrylic acid(PAA)/MXene fiber membrane by electrospinning.After heat treatment of film and subsequent modification with Pd nanoparticles,PVA/PAA/MXene@PdNPs composite nanofiber membrane with high specific surface area and excellent catalytic performance was finally prepared.The uniform distribution of MXene sheets in the composite fiber membrane not only solves the problem that the MXene sheet is not easy to be monolayerized,but also can grow the self-reduced Pd nanoparticles on the MXene sheets.In addition,the composite nanofiber membrane exhibits excellent catalytic ability and cycle stability for 4-nitrophenol(4-NP)and 2-nitrophenol(2-NA),providing new strategy for the study of catalytic composite materials related to degradation of wastewater.
基金supported by the National Natural Science Foundation of China(20774057,50633010,20874060 &50873058)National Basic Research Program(2007CB808000 & 2009CB930400)+3 种基金the Program for New Century Excellent Talents in University(NCET-07-0558)the Foundation for the Author of National Excellent Doctoral Dissertation of Chinathe Fok Ying Tung Education Foundation(114029)the Shanghai Leading Academic Discipline Project(B202)
文摘A novel hyperbranched multiarm copolymer of HBPO-star-PDEAEMA with a hydrophobic poly(3-ethyl-3-(hydroxymethyl) oxetane)(HBPO) core and many cationic poly(2-(N,N-diethylamino) ethyl methacrylate)(PDEAEMA) arms has been synthesized through an atom transfer radical polymerization(ATRP) method,and been applied to spontaneously reduce and stabilize gold nanoparticles(AuNPs) in water without other additional agents.The size of the nanoparticles could be effectively controlled at about 4 nm,and the nanoparticles are extremely stable in solution without aggregation even for one year.It was found that solution pH and the molar ratio of N/Au have certain effects on the size and stability of AuNPs.This work provides a simple method for the synthesis of uniform and highly stable AuNPs.
基金Project supported by Cooperation Project in Industry, Education and Research of Guangdong Province and Ministry of Education of China （2012B09110044）, and the Guangdong Provincial Natural Science Foundation of China （9151009001000052 ）
文摘A series of blue long afterglow mixed halide-phosphate phosphors Sr5 （PO4）3 FxCll-x：Eu2＋,Gd3＋ were synthesized in air by traditional solid-state reaction routte. The crystal structures, photoluminescence, thermolurninescenee properties and afterglow proper- ties of the phosphors were characterized systematically using X-ray diffraction （XRD）, luminescence spectrophotometer, microcom- puter thermoluminescence dosimeter and single photon counter, respectively. Under 280 nm excitation, the broadband emissions of Eu2＋ ions were observed at 445 nm （blue） due to the 4f7→4f65d transition. It was demonstrated that there existed the self-reduction of the Eu3＋ to Eu2＋ ions in this special halide-phosphate matrix in air condition. The addition of Gd3＋ ions obviously enhanced the after- glow properties of the single doped Eu2＋ ions in the halide-phosphate phosphors. And the content of the fluoride anions also had sig- nificant influence on the afterglow properties. All results indicated that Srs （PO4）3 FxCI1-x：Eu2＋,Gd3＋ might be potential phosphors for long lasting phosphorescence （LLP） materials.
基金We thank the National Natural Science Foundation of China，the Program for New Century Excellent Talents in University of Ministry of Education of China，the Fundamental Research Funds for Central Universities
文摘A series of luminescent Ba0.79Al10.9O17.14∶xEu (x=0.005-0.12) phosphors were prepared by high-temperature solid-state reaction in air atmosphere.The coexistence of Eu2+ and Eu3+ was observed and verified by photoluminescence (PL) and photoluminescence excitation (PLE) spectra,X-ray photoelectron spectra (XPS),and diffuse reflection spectra.The band emission peaking at 430 nm was assigned to 4F65D-4F7 transition of Eu2+,and another four emissions peaking at 589,619,655,and 704 nm were attributed to 4F-4F transitions of 5D0-7FJ(J=1,2,3,4) of Eu3+.The related mechanism of self-reduction was discussed in detail.The color of the Ba0.79Al10.9O17.14∶xEu phosphors could be shifted from blue (0.23,0.10) to red (0.42,0.27) by doping Li+ ions,and the temperature dependence properties were investigated.
