Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4...Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.展开更多
Solar vapor generation(SVC)represents a promising technique for seawater desalination to alleviate the global water crisis and energy shortage.One of its main bottleneck problems is that the evaporation efficiency and...Solar vapor generation(SVC)represents a promising technique for seawater desalination to alleviate the global water crisis and energy shortage.One of its main bottleneck problems is that the evaporation efficiency and stability are limited by salt crystallization under high-salinity brines.Herein,we demonstrate that the 3D porous melamine-foam(MF)wrapped by a type of self-assembling composite materials based on reduced polyoxometalates(i.e.heteropoly blue,HPB),oleic acid(OA),and polypyrrole(PPy)(labeled with MF@HPB-PPy_(n)-OA)can serve as efficient and stable SVC material at high salinity.Structural characterizations of MF@HPB-PPy_(n)-OA indicate that both hydrophilic region of HPBs and hydrophobic region of OA co-exist on the surface of composite materials,optimizing the hydrophilic and hydrophobic interfaces of the SVC materials,and fully exerting its functionality for ultrahigh water-evaporation and anti-salt fouling.The optimal MF@HPB-PPy_(10)-OA operates continuously and stably for over 100 h in 10wt%brine.Furthermore,MF@HPB-PPy_(10)-OA accomplishes complete salt-water separation of 10wt%brine with 3.3kgm^(-2)h^(-1)under 1-sun irradiation,yielding salt harvesting efficiency of 96.5%,which belongs to the record high of high-salinity systems reported so far and is close to achieving zero liquid discharge.Moreover,the low cost of MF@HPB-PPy_(10)-OA(2.56$m^(-2))suggests its potential application in the practical SVC technique.展开更多
α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the wi...α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.展开更多
Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using dif...Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using different cancer cell lines,the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains.Cell colony formation assay,autophagy detection,mitochondrial observation,qRT-PCR,Western blotting,and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.Results MO-4,a Lindqvist-type POM linking a proline at its side strain,was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells.It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells.Mechanistically,MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species(ROS)levels and resulting in apoptosis.In vivo,breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.Conclusion Collectively,the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.展开更多
Heterogeneously catalyzed hydrolytic dehydrogenation of ammonia borane is a remarkable structure sensitive reaction. In this work, a strategy by using polyoxometalates(POMs) as the ligands is proposed to engineer the ...Heterogeneously catalyzed hydrolytic dehydrogenation of ammonia borane is a remarkable structure sensitive reaction. In this work, a strategy by using polyoxometalates(POMs) as the ligands is proposed to engineer the surface and electronic properties of Pt/CNT catalysts toward the enhanced hydrogen generation rate and durability. Three kinds of POMs, i.e., silicotungstic acid(STA), phosphotungstic acid(PTA)and molybdophosphoric acid(PMA), are comparatively studied, among which the STA shows positive effects on the catalytic activity and durability. A catalyst structure-performance relationship is established by a combination of kinetic and isotopic analyses with multiple characterization techniques, such as HAADF-STEM, EDS, Raman spectroscopy and XPS. It is shown that the STA compared to the other two POMs can increase the Pt binding energy and thus promote the reaction. The insights demonstrated here could open a new avenue for boosting the reaction by employing the POMs as the ligands to engineer the catalyst electronic properties.展开更多
Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for de...Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone （2-PAP）, was investigated over several ce-sium-exchanged polyoxometalate （Cs-POM） catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms： an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions： promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP （〉99%） with excellent selectivities to the desired products （98.6% for phenol and 91.1% for acetophenone） can be achieved.展开更多
Bismuth‐based photocatalysts are a class of excellent visible‐light photocatalysts;however,their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low,limiting their develo...Bismuth‐based photocatalysts are a class of excellent visible‐light photocatalysts;however,their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low,limiting their development and application in the field of photocatalysis.To address these issues,a series of polyoxometalate PW_(12)O_(40)^(3–)‐doped Bi_(2)O_(3–x)/Bi Schottky photocatalysts PW_(12)@Bi_(2)O_(3–x)/Bi‐n(PBOB‐n,where n is the amount of NaBH4,i.e.,6,12,18,24,and 48 mg)were prepared by a simple electrospinning/calcination/in‐situ NaBH4 reduction method.In this composite photocatalyst,the doping of PW_(12) could effectively adjust the electronic structure of Bi_(2)O_(3–x) and improve its redox properties.As a shallow electron trap,PW_(12) promoted the separation of the photogenerated carriers.Furthermore,desirable Schottky junction between the metal Bi nanoparticles and PW_(12)@Bi_(2)O_(3–x) further accelerated the separation of the photogenerated carriers.The synergistic effect of the aforementioned factors endowed PBOB‐n with excellent photocatalytic activity.Among the samples,PBOB‐18 exhibited superior photocatalytic activity.Under visible‐light irradiation,93.7%(20 mg catalyst)of 20 ppm tetrabromobisphenol A(TBBPA,20 mL)was degraded in 60 min.Its activity was 4.4 times higher than that of Bi_(2)O_(3).PBOB‐18 also exhibited an ultrahigh photocatalytic performance for the removal of NO.Its removal rate(600 ppb)reached 83.3%in 30 min,making it one of the most active Bi‐based photocatalysts.Furthermore,the photocatalytic mechanisms of PBOB‐18 for TBBPA and NO have been proposed.This work provides a new direction and reference for the design of low‐cost,efficient,stable,and versatile photocatalysts.展开更多
A series of photocatalysts, K11[Ln(PW11O39)2]/PVA (Ln=La, Ce, Pr, Nd, Sm) were prepared by K11[Ln(PW11O39)2] (Ln=La, Ce, Pr, Nd, Sm) containing five kinds of lanthanides and polyvinyl alcohol as the support. The catal...A series of photocatalysts, K11[Ln(PW11O39)2]/PVA (Ln=La, Ce, Pr, Nd, Sm) were prepared by K11[Ln(PW11O39)2] (Ln=La, Ce, Pr, Nd, Sm) containing five kinds of lanthanides and polyvinyl alcohol as the support. The catalysts obtained were characterized by Fourier transform infrared spectra, UV-vis spectra, powder X-ray diffraction, and scanning electron microscopy, indicating that the structure of K11[Ln(PW11O39)2] and polyvinyl alcohol remained intact, respectively. The photocatalysts exhibited efficient catalytic activity to degrade methyl orange, Congo Red, Ponceau 2R. The maximal degradation conversions of the three kinds of dyes were 99.58%, 47.61%, 72.42%, respectively.展开更多
Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were repro...Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were reproducibly grown at each adsorption cycle as monitored by UV spectroscopy.展开更多
Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR,...Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR, TGA and single-crystal X-ray structural analyses. The results of X-ray crystallography analyses exhibit that 1 consists of one a-Keggin anion [a-H5PW11CoO40]2- and one isolated [Co（2,2＇-bipy）3]2＋ complex, while 2 is constructed from one a-Keggin anion [a- HBW12O40]4- and two isolated [Fe（2,2＇-bipy）3]2＋ cations. The data for 1： orthorhombic system, space group Pbcn, a = 16.062（6）, b = 27.278（10）, c = 16.951（6）A, V = 7427（5）A3 and Z = 4; and those for 2： triclinic system, space group P1, a = 13.787（3）, b = 17.857（5）, c = 18.918（5）A, a = 88.009（12）, β = 72.768（10）, γ = 74.935（10）°, V = 4291（2）A3 and Z = 2.展开更多
The composite films, XW11O39n-/SiO2, (X refers to Si, Ge or P, respectively) were prepared by tetraethoxysilane (TEOS) hydrolysis sol-gel method via spin-coating technique. Formation of the composite films is due to s...The composite films, XW11O39n-/SiO2, (X refers to Si, Ge or P, respectively) were prepared by tetraethoxysilane (TEOS) hydrolysis sol-gel method via spin-coating technique. Formation of the composite films is due to strong chemical reaction of organic silanol group with the surface oxygen atoms of XW11O39n-, resulted in the saturation of the surface of the lacunary polyoxometalates (POMs). Therefore, the coordination structural model of the films was proposed. As for the films, retention of the primary Keggin structure was confirmed by UV-vis, FT-IR spectra and MAS NMR. The surface morphology of the films was characterized by SEM, indicating that the film surface is relatively uniform, and the layer thickness is in the range of 250~350 nm. Aqueous formic acid (FA) (0-20 mmol/L) was degraded into CO2 and H2O by irradiating the films in the near-UV area. The results show that all the films have photocatalytic activities and the degradation reaction follows Langmuir-Hinshelwood first order kinetics.展开更多
The salts of para-tungstic and para-molybdic were heterogenized for their effective use as solid catalysts in the transesterification reaction of dimethyl carbonate and phenol by inserting them between the layers of M...The salts of para-tungstic and para-molybdic were heterogenized for their effective use as solid catalysts in the transesterification reaction of dimethyl carbonate and phenol by inserting them between the layers of Mg2Al-hydrotalcite. These catalysts were characterized by FT-IR spectra and X-ray powder diffraction. Polyoxometalates （POMs） clusters were intercalated into the interlayer of layered double hydroxide （LDH） via anion exchange with organic acid precursor in Mg2Al-LDH, and the integrity of the clusters [W7O24 ]^6- and [Mo7O24 ]^6- was maintained. The intercalated para-molybdic cluster showed high catalytic activity and reusability in the transesterification under mild reaction conditions. When the reaction was carried out at 180 ℃, with a molar ratio of phenol to DMC of 1 ： 1, a reaction time 10 h, and a catalyst amount 1% （wt）, the conversion of phenol was 10.0 %, the selectivities of diphenyl carbonate and methyl phenyl carbonate were 10.7 % and 86.1%, respectively.展开更多
A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keg...A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on r GO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation（FAOR）. Especially, the Pd/PW（12）/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites（POMs = PW（12）, SiW（12）, PMo（12））.展开更多
Nanocluster polyoxometalates with a structure of buckyball (fullerene) are a promising means of targeted delivery of drugs in the body. In this paper, based on an analysis of histological sections of liver and kidney ...Nanocluster polyoxometalates with a structure of buckyball (fullerene) are a promising means of targeted delivery of drugs in the body. In this paper, based on an analysis of histological sections of liver and kidney and peripheral blood, showed a significant reduction of toxicity of buckyballs, containing ions of molybdenum (VI), the substitution of Mo (V) ions to Fe (III), in contrast to buckyballs based on Mo (V). The absence of accumulation of molybdenum in rats with a daily intramuscular injection of aqueous solutions of both drugs within a month was confirmed.展开更多
All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,...All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.展开更多
Via layer-by-layer assembly, the polyoxometalates of Keggin type, SiW_ 11O_ 39Ni(H_2O) 6-(SiNiW_ 11) and {SiW_ 11O_ 39Mn(H_2O) 6-}(SiMnW_ 11) were first immobilized on a 4-aminothiophenol(4-ATP) modified glassy carbon...Via layer-by-layer assembly, the polyoxometalates of Keggin type, SiW_ 11O_ 39Ni(H_2O) 6-(SiNiW_ 11) and {SiW_ 11O_ 39Mn(H_2O) 6-}(SiMnW_ 11) were first immobilized on a 4-aminothiophenol(4-ATP) modified glassy carbon electrode surface. The electrochemical behavior of these polyoxometalates was investigated. They exhibited some special properties in the films, which are different from those in a homogeneous aqueous solution. Their reaction mechanism in a multilayer film is proposed. The electrocatalytic behavior of these multilayer film electrodes for the reduction of BrO-_3 and NO-_2 were comparatively studied.展开更多
The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was ...The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was demonstrated that oxidizing sites not only took dominating part in the activation of isobutane, but also influenced the product distribution. Besides, appropriate Cs addition led to moderate acidity of catalysts, favoring the selectivity to desired products. Furthermore, to obtain partially reduced catalysts, different calcination atmospheres were investigated and certain proportion of Mo^（5＋） produced during calcination was crucial for the redox reaction. The catalyst calcined in N2 showed the highest yield of MAA（7.0%）. Fe-substitution enhanced the activity of catalysts by rapid reoxidation of Mo^（5＋）.展开更多
Polyoxometalates have been explored as multi-electron active species in both aqueous and non-aqueous redox flow batteries. Although non-aqueous systems in principle offer a wider voltage window for redox flow battery ...Polyoxometalates have been explored as multi-electron active species in both aqueous and non-aqueous redox flow batteries. Although non-aqueous systems in principle offer a wider voltage window for redox flow battery operation, realization of this potential requires a judicious choice of solvent as well as polyoxometalate properties. We demonstrate here the superior performance of N,N-dimethylformamide(DMF)compared to acetonitrile as a solvent for redox flow batteries based on Li3PMo12O40. This compound displays two 1-electron transfers in acetonitrile but can access an extra quasi-reversible 2-electron redox process in DMF. A cell containing 10 mM solution of Li3PMo12O40 in DMF produced a cell voltage of 0.7 V with 2-electron transfers(State of Charge = 60%) and showed a good cyclability. As a means to boost energy density, operation of the redox flow battery at a higher concentration of 0.1 M Li3PMo12O40 produced cells with cell voltage of 0.6 V in acetonitrile and a cell voltage of 1.0 V in DMF;both showed excellent coulombic efficiencies of more than 90% over the course of 30 cycles. Energy density was also increased by employing an asymmetric cell with different polyoxometalates on each side to extend cell voltage.Li6P2W18O62 exhibited 3 quasi-reversible 2-electron transfers in the potential range between-2.05 V and-0.5 V vs. Ag/Ag+. 10 mM Li6P2W18O62/Li3PMo12O40 in DMF produced a cell with cell voltage of 1.3 V involving 4-electron transfers(State of Charge = 50%) with coulombic efficiency of nearly 100% and energy efficiency of nearly 70% throughout the test with more than 20 cycles. These promising results demonstrate proof-of-concept approaches to improving the performance of polyoxometalates in non-aqueous redox flow batteries.展开更多
Carbon nanotubes and graphene are carbon-based materials, which possess not only unique structure but also prop- erties such as high surface area, extraordinary mechanical properties, high electronic conductivity, and...Carbon nanotubes and graphene are carbon-based materials, which possess not only unique structure but also prop- erties such as high surface area, extraordinary mechanical properties, high electronic conductivity, and chemical stability. Thus, they have been regarded as an important material, especially for exploring a variety of complex catalysts. Considerable efforts have been made to functionalize and fabricate carbon-based composites with metal nanoparticles. In this review, we summarize the recent progress of our research on the decoration of carbon nanotubes/graphene with metal nanoparticles by using polyoxometalates as key agents, and their enhanced photo-electrical catalytic activities in various catalytic reactions. The polyoxometalates play a key role in constructing the nanohybrids and contributing to their photo-electrical catalytic properties.展开更多
基金the financial support from the Key Research and Development Program sponsored by the Ministry of Science and Technology(MOST)(2022YFB4002000,2022YFA1203400)the National Natural Science Foundation of China(22102172,22072145,22372155,22005294,21925205,21721003)。
文摘Constructing heterostructured nanohybrid is considered as a prominent route to fabricate alternative electrocatalysts to commercial Pt/C for hydrogen evolution reaction(HER).In this work,(NH_(4))_(4)[NiH_(6)Mo_(6)O_(4)]·5H_(2)O polyoxometalates(NiMo_(6))are adopted as the cluster precursors for simple fabrication of heterostructured Pt-Ni_(3)Mo_(3)N nanohybrids supported by carbon black(Pt-Ni_(3)Mo_(3)N/C)without using additional N sources.The improved porosity and enhanced electronic interaction of Pt-Ni_(3)Mo_(3)N/C should be attributed to the integration of Pt with NiMo_(6),which favors the mass transport,promotes the formation of exposed catalytic sites,and benefits the regulation of intrinsic activity.Thus,the as-obtained Pt-Ni_(3)Mo_(3)N/C exhibits impressive and durable HER performance as indicated by the low overpotential of 13.7 mV at the current density of 10 mA cm^(-2) and the stable overpotential during continuous working at 100 mA cm^(-2) for 100 h.This work provides significant insights for the synthesis of new highly active heterostructured electrocatalysts for renewable energy devices.
基金financially supported by the National Key Basic Research Program of China(grant no.2020YFA0406101)National Natural Science Foundation of China(grant nos.22171041,22071020,21901035,22271043)+1 种基金Natural Science Foundation of Jilin Province Science and Technology Department(grant nos.20230508094RC,20220101045JC)the Fundamental Research Funds for the Central Universities(grant no.2412021QD008)
文摘Solar vapor generation(SVC)represents a promising technique for seawater desalination to alleviate the global water crisis and energy shortage.One of its main bottleneck problems is that the evaporation efficiency and stability are limited by salt crystallization under high-salinity brines.Herein,we demonstrate that the 3D porous melamine-foam(MF)wrapped by a type of self-assembling composite materials based on reduced polyoxometalates(i.e.heteropoly blue,HPB),oleic acid(OA),and polypyrrole(PPy)(labeled with MF@HPB-PPy_(n)-OA)can serve as efficient and stable SVC material at high salinity.Structural characterizations of MF@HPB-PPy_(n)-OA indicate that both hydrophilic region of HPBs and hydrophobic region of OA co-exist on the surface of composite materials,optimizing the hydrophilic and hydrophobic interfaces of the SVC materials,and fully exerting its functionality for ultrahigh water-evaporation and anti-salt fouling.The optimal MF@HPB-PPy_(10)-OA operates continuously and stably for over 100 h in 10wt%brine.Furthermore,MF@HPB-PPy_(10)-OA accomplishes complete salt-water separation of 10wt%brine with 3.3kgm^(-2)h^(-1)under 1-sun irradiation,yielding salt harvesting efficiency of 96.5%,which belongs to the record high of high-salinity systems reported so far and is close to achieving zero liquid discharge.Moreover,the low cost of MF@HPB-PPy_(10)-OA(2.56$m^(-2))suggests its potential application in the practical SVC technique.
基金supported by the National Natural Science Foundation of China(under grant numbers 12174272 and 11974136)。
文摘α-Keggin polyoxometalates(POMs)[XW_(12)O_(40)]^(n−)(X=Al,Si,P,S)are widely used in batteries owing to their remarkable redox activity.However,the mechanism underlying the applications appears inconsistent with the widely accepted covalent bonding nature.Here,first-principles calculations show that XW_(12)are core–shell structures composed of a shell and an XO_(4)^(n−)core,both are stabilized by covalent interactions.Interestingly,owing to the presence of a substantial number of electrons in W_(12)O_(36)shell,the frontier molecular orbitals of XW_(12)are not only strongly delocalized but also exhibit superatomic properties with high-angular momentum electrons that do not conform to the Jellium model.Detailed analysis indicates that energetically high lying filled molecular orbitals(MOs)have reached unusually high-angular momentum characterized by quantum number K or higher,allowing for the accommodation of numerous electrons.This attribute confers strong electron acceptor ability and redox activity to XW_(12).Moreover,electrons added to XW_(12)still occupy the K orbitals and will not cause rearrangement of the MOs,thereby maintaining the stability of these structures.Our findings highlight the structure–activity relationship and provide a direction for tailor-made POMs with specific properties at atomic level.
基金supported by Open Project Funding of the Key Laboratory of Fermentation Engineering(Ministry of Education)(No.202209EF09)the Natural Science Foundation of Hubei Province(No.2021CFB289)+1 种基金the Key R&D Project of Hubei Province(No.2022BCA018)the initial funding of Hubei University of Technology(No.XJ2022002201).
文摘Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using different cancer cell lines,the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains.Cell colony formation assay,autophagy detection,mitochondrial observation,qRT-PCR,Western blotting,and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.Results MO-4,a Lindqvist-type POM linking a proline at its side strain,was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells.It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells.Mechanistically,MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species(ROS)levels and resulting in apoptosis.In vivo,breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.Conclusion Collectively,the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.
基金supported by the National Natural Science Foundation of China(21776077)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning+3 种基金the Shanghai Rising-Star Program(17QA1401200)the Open Project of SKLOCE(SKL-Che-15C03)the Shanghai Natural Science Foundation(17ZR1407300 and 17ZR1407500)the State Key Laboratory of Organic-Inorganic Composites(oic201801007)。
文摘Heterogeneously catalyzed hydrolytic dehydrogenation of ammonia borane is a remarkable structure sensitive reaction. In this work, a strategy by using polyoxometalates(POMs) as the ligands is proposed to engineer the surface and electronic properties of Pt/CNT catalysts toward the enhanced hydrogen generation rate and durability. Three kinds of POMs, i.e., silicotungstic acid(STA), phosphotungstic acid(PTA)and molybdophosphoric acid(PMA), are comparatively studied, among which the STA shows positive effects on the catalytic activity and durability. A catalyst structure-performance relationship is established by a combination of kinetic and isotopic analyses with multiple characterization techniques, such as HAADF-STEM, EDS, Raman spectroscopy and XPS. It is shown that the STA compared to the other two POMs can increase the Pt binding energy and thus promote the reaction. The insights demonstrated here could open a new avenue for boosting the reaction by employing the POMs as the ligands to engineer the catalyst electronic properties.
基金supported by the National Key Basic Research Program of China(973 program,2013CB934101)National Natural Science Foundation of China(21433002,21573046)+1 种基金China Postdoctoral Science Foundation(2016M601492)International Science and Technology Cooperation Projects of Guangxi(15104001-5)~~
文摘Production o f aromatics from lignin has attracted much attention. Because of the coexistence of C-O and C-C bonds and their complex combinations in the lignin macromolecular network, a plausible roadmap for developing a lignin catalytic decomposition process could be developed by exploring the transformation mechanisms of various model compounds. Herein, decomposition of a lignin model compound, 2-phenoxyacetophenone （2-PAP）, was investigated over several ce-sium-exchanged polyoxometalate （Cs-POM） catalysts. Decomposition of 2-PAP can follow two dif-ferent mechanisms： an active hydrogen transfer mechanism or an oxonium cation mechanism. The mechanism for most reactions depends on the competition between the acidity and redox proper-ties of the catalysts. The catalysts of POMs perform the following functions： promoting active hy-drogen liberated from ethanol and causing formation of and then temporarily stabilizing oxonium cations from 2-PAP. The use of Cs-PMo, which with strong redox ability, enhances hydrogen libera-tion and promotes liberated hydrogen transfer to the reaction intermediates. As a consequence, complete conversion of 2-PAP （〉99%） with excellent selectivities to the desired products （98.6% for phenol and 91.1% for acetophenone） can be achieved.
文摘Bismuth‐based photocatalysts are a class of excellent visible‐light photocatalysts;however,their redox activity is relatively poor and the efficiency of photogenerated carrier separation is low,limiting their development and application in the field of photocatalysis.To address these issues,a series of polyoxometalate PW_(12)O_(40)^(3–)‐doped Bi_(2)O_(3–x)/Bi Schottky photocatalysts PW_(12)@Bi_(2)O_(3–x)/Bi‐n(PBOB‐n,where n is the amount of NaBH4,i.e.,6,12,18,24,and 48 mg)were prepared by a simple electrospinning/calcination/in‐situ NaBH4 reduction method.In this composite photocatalyst,the doping of PW_(12) could effectively adjust the electronic structure of Bi_(2)O_(3–x) and improve its redox properties.As a shallow electron trap,PW_(12) promoted the separation of the photogenerated carriers.Furthermore,desirable Schottky junction between the metal Bi nanoparticles and PW_(12)@Bi_(2)O_(3–x) further accelerated the separation of the photogenerated carriers.The synergistic effect of the aforementioned factors endowed PBOB‐n with excellent photocatalytic activity.Among the samples,PBOB‐18 exhibited superior photocatalytic activity.Under visible‐light irradiation,93.7%(20 mg catalyst)of 20 ppm tetrabromobisphenol A(TBBPA,20 mL)was degraded in 60 min.Its activity was 4.4 times higher than that of Bi_(2)O_(3).PBOB‐18 also exhibited an ultrahigh photocatalytic performance for the removal of NO.Its removal rate(600 ppb)reached 83.3%in 30 min,making it one of the most active Bi‐based photocatalysts.Furthermore,the photocatalytic mechanisms of PBOB‐18 for TBBPA and NO have been proposed.This work provides a new direction and reference for the design of low‐cost,efficient,stable,and versatile photocatalysts.
基金Project supported by China Academy of Engineering Physics (6260107025)
文摘A series of photocatalysts, K11[Ln(PW11O39)2]/PVA (Ln=La, Ce, Pr, Nd, Sm) were prepared by K11[Ln(PW11O39)2] (Ln=La, Ce, Pr, Nd, Sm) containing five kinds of lanthanides and polyvinyl alcohol as the support. The catalysts obtained were characterized by Fourier transform infrared spectra, UV-vis spectra, powder X-ray diffraction, and scanning electron microscopy, indicating that the structure of K11[Ln(PW11O39)2] and polyvinyl alcohol remained intact, respectively. The photocatalysts exhibited efficient catalytic activity to degrade methyl orange, Congo Red, Ponceau 2R. The maximal degradation conversions of the three kinds of dyes were 99.58%, 47.61%, 72.42%, respectively.
基金This project was supported by the National Natural Science Foundation of China(20071004)Beijing Natural Science Foundation(2002007)Scientific Research Foundation for the Retumed Overseas Chinese Scholars,State Education Ministry,to KZW.
文摘Hybrid self-assembled multilayer films were prepared by alternate adsorption of 1,10-diaminodecane (1,10-DAD) and Keggin polyoxometalates of SiW12O404-, SiW11VO405-, and PMo12O403-, respectively. The films were reproducibly grown at each adsorption cycle as monitored by UV spectroscopy.
基金Supported by the National Natural Science Fund for Distinguished Young Scholars of China (No. 20725101)the NNSFC (Nos. 50872133 and 20821061)+2 种基金the 973 Program (No. 2006CB932904)the NSF of Fujian Province (No. E0510030)the Knowledge Innovation Program of CAS
文摘Two new hybrid polyoxotungstates, [Co（2,2＇-bipy）3][a-H5PW11CoO40]-3H2O 1 and [Fe（2,2＇-bipy）3]2[a-HBW12O40]-2.5H2O 2 （2,2＇-bipy = 2,2＇-dipyridyl）, have been hydrothermally synthesized and characterized by IR, TGA and single-crystal X-ray structural analyses. The results of X-ray crystallography analyses exhibit that 1 consists of one a-Keggin anion [a-H5PW11CoO40]2- and one isolated [Co（2,2＇-bipy）3]2＋ complex, while 2 is constructed from one a-Keggin anion [a- HBW12O40]4- and two isolated [Fe（2,2＇-bipy）3]2＋ cations. The data for 1： orthorhombic system, space group Pbcn, a = 16.062（6）, b = 27.278（10）, c = 16.951（6）A, V = 7427（5）A3 and Z = 4; and those for 2： triclinic system, space group P1, a = 13.787（3）, b = 17.857（5）, c = 18.918（5）A, a = 88.009（12）, β = 72.768（10）, γ = 74.935（10）°, V = 4291（2）A3 and Z = 2.
文摘The composite films, XW11O39n-/SiO2, (X refers to Si, Ge or P, respectively) were prepared by tetraethoxysilane (TEOS) hydrolysis sol-gel method via spin-coating technique. Formation of the composite films is due to strong chemical reaction of organic silanol group with the surface oxygen atoms of XW11O39n-, resulted in the saturation of the surface of the lacunary polyoxometalates (POMs). Therefore, the coordination structural model of the films was proposed. As for the films, retention of the primary Keggin structure was confirmed by UV-vis, FT-IR spectra and MAS NMR. The surface morphology of the films was characterized by SEM, indicating that the film surface is relatively uniform, and the layer thickness is in the range of 250~350 nm. Aqueous formic acid (FA) (0-20 mmol/L) was degraded into CO2 and H2O by irradiating the films in the near-UV area. The results show that all the films have photocatalytic activities and the degradation reaction follows Langmuir-Hinshelwood first order kinetics.
基金Sponsored by the National Natural Science Foundation of China(20671011,20731002)Foundation Research Project of BeijingInstitute of Technology(20060742022)+1 种基金the"111"Project(B07012)Key Laboratory of Structural Chemistry Foundation(060017)
文摘The salts of para-tungstic and para-molybdic were heterogenized for their effective use as solid catalysts in the transesterification reaction of dimethyl carbonate and phenol by inserting them between the layers of Mg2Al-hydrotalcite. These catalysts were characterized by FT-IR spectra and X-ray powder diffraction. Polyoxometalates （POMs） clusters were intercalated into the interlayer of layered double hydroxide （LDH） via anion exchange with organic acid precursor in Mg2Al-LDH, and the integrity of the clusters [W7O24 ]^6- and [Mo7O24 ]^6- was maintained. The intercalated para-molybdic cluster showed high catalytic activity and reusability in the transesterification under mild reaction conditions. When the reaction was carried out at 180 ℃, with a molar ratio of phenol to DMC of 1 ： 1, a reaction time 10 h, and a catalyst amount 1% （wt）, the conversion of phenol was 10.0 %, the selectivities of diphenyl carbonate and methyl phenyl carbonate were 10.7 % and 86.1%, respectively.
基金financially supported by the National Natural Science Foundation of China(No.21571034)the Natural Science Foundation of Fujian Province(No.2014J01033)a Key Item of Education Department of Fujian Province(No.JA13085)
文摘A novel ternary nanocomposite, Pd nanoparticles（NPs）/polyoxometalates（POMs）/reduced graphene oxide（rGO）, was prepared by a green, mild, electrochemical-reductionassisted assembly. It is worth noting that the Keggin-type POM acts as an electrocatalyst as well as a bridging molecule. During the reduction process, POMs transfer the electrons from the electrode to GO, leading to a deep reduction of GO and the content of oxygen-containing groups is decreased to around 6.1%. Meanwhile, the strong adsorption effect between the POM clusters and rGO nanosheets induces the spontaneous assembly of POM on r GO in a uniformly dispersed state, forming a nanocomposite. The ternary Pd NPs/POMs/rGO nanocomposite exhibits higher electrocatalytic activities, better electrochemical stability, and higher resistance to CO poisoning than the Pd/C catalyst towards the formic acid oxidation（FAOR）. Especially, the Pd/PW（12）/rGO exhibits the best electrocatalytic performance among three Pd/POMs/rGO composites（POMs = PW（12）, SiW（12）, PMo（12））.
文摘Nanocluster polyoxometalates with a structure of buckyball (fullerene) are a promising means of targeted delivery of drugs in the body. In this paper, based on an analysis of histological sections of liver and kidney and peripheral blood, showed a significant reduction of toxicity of buckyballs, containing ions of molybdenum (VI), the substitution of Mo (V) ions to Fe (III), in contrast to buckyballs based on Mo (V). The absence of accumulation of molybdenum in rats with a daily intramuscular injection of aqueous solutions of both drugs within a month was confirmed.
文摘All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.
文摘Via layer-by-layer assembly, the polyoxometalates of Keggin type, SiW_ 11O_ 39Ni(H_2O) 6-(SiNiW_ 11) and {SiW_ 11O_ 39Mn(H_2O) 6-}(SiMnW_ 11) were first immobilized on a 4-aminothiophenol(4-ATP) modified glassy carbon electrode surface. The electrochemical behavior of these polyoxometalates was investigated. They exhibited some special properties in the films, which are different from those in a homogeneous aqueous solution. Their reaction mechanism in a multilayer film is proposed. The electrocatalytic behavior of these multilayer film electrodes for the reduction of BrO-_3 and NO-_2 were comparatively studied.
基金supported by the National Natural Science Foundation of China(No.U1362201)the National 973 Program of China(No.2012CB215006)
文摘The catalytic performance of Cs-substituted phosphomolybdic salts was studied for selective oxidation of isobutane. The results of activity tests revealed that 360 °C was the optimal reaction temperature. It was demonstrated that oxidizing sites not only took dominating part in the activation of isobutane, but also influenced the product distribution. Besides, appropriate Cs addition led to moderate acidity of catalysts, favoring the selectivity to desired products. Furthermore, to obtain partially reduced catalysts, different calcination atmospheres were investigated and certain proportion of Mo^（5＋） produced during calcination was crucial for the redox reaction. The catalyst calcined in N2 showed the highest yield of MAA（7.0%）. Fe-substitution enhanced the activity of catalysts by rapid reoxidation of Mo^（5＋）.
文摘Polyoxometalates have been explored as multi-electron active species in both aqueous and non-aqueous redox flow batteries. Although non-aqueous systems in principle offer a wider voltage window for redox flow battery operation, realization of this potential requires a judicious choice of solvent as well as polyoxometalate properties. We demonstrate here the superior performance of N,N-dimethylformamide(DMF)compared to acetonitrile as a solvent for redox flow batteries based on Li3PMo12O40. This compound displays two 1-electron transfers in acetonitrile but can access an extra quasi-reversible 2-electron redox process in DMF. A cell containing 10 mM solution of Li3PMo12O40 in DMF produced a cell voltage of 0.7 V with 2-electron transfers(State of Charge = 60%) and showed a good cyclability. As a means to boost energy density, operation of the redox flow battery at a higher concentration of 0.1 M Li3PMo12O40 produced cells with cell voltage of 0.6 V in acetonitrile and a cell voltage of 1.0 V in DMF;both showed excellent coulombic efficiencies of more than 90% over the course of 30 cycles. Energy density was also increased by employing an asymmetric cell with different polyoxometalates on each side to extend cell voltage.Li6P2W18O62 exhibited 3 quasi-reversible 2-electron transfers in the potential range between-2.05 V and-0.5 V vs. Ag/Ag+. 10 mM Li6P2W18O62/Li3PMo12O40 in DMF produced a cell with cell voltage of 1.3 V involving 4-electron transfers(State of Charge = 50%) with coulombic efficiency of nearly 100% and energy efficiency of nearly 70% throughout the test with more than 20 cycles. These promising results demonstrate proof-of-concept approaches to improving the performance of polyoxometalates in non-aqueous redox flow batteries.
基金Project supported by the National Natural Science Foundation of China(Grant No.21371173)the National Basic Research Program of China(973 Program)(Grant No.2012CB932504)
文摘Carbon nanotubes and graphene are carbon-based materials, which possess not only unique structure but also prop- erties such as high surface area, extraordinary mechanical properties, high electronic conductivity, and chemical stability. Thus, they have been regarded as an important material, especially for exploring a variety of complex catalysts. Considerable efforts have been made to functionalize and fabricate carbon-based composites with metal nanoparticles. In this review, we summarize the recent progress of our research on the decoration of carbon nanotubes/graphene with metal nanoparticles by using polyoxometalates as key agents, and their enhanced photo-electrical catalytic activities in various catalytic reactions. The polyoxometalates play a key role in constructing the nanohybrids and contributing to their photo-electrical catalytic properties.
