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
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
With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of variou...With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N2adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.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
Aiming at deep desulfurization of gasoline,three amphiphilic catalysts [C18H37N(CH3)3]3+x [PMo12-xVxO40](x=1,2,or 3) were prepared and characterized.The amphiphilic vanadium(V)-substituted polyoxometalates were dissol...Aiming at deep desulfurization of gasoline,three amphiphilic catalysts [C18H37N(CH3)3]3+x [PMo12-xVxO40](x=1,2,or 3) were prepared and characterized.The amphiphilic vanadium(V)-substituted polyoxometalates were dissolved in water-immiscible ionic liquid([Bmim]PF6),forming a H2O2-in-[Bmim]PF6 emulsion desulfurization system with 30 m% H2O2 serving as the oxidant.The catalytic oxidation of sulfur-containing model oil has been studied in detail under various reaction conditions using this system.The ionic liquid emulsion system showed high catalytic oxidative activity in the treatment of commodity gasoline.Furthermore,the mechanism of catalytic oxidative desulfurization was also elaborated.展开更多
The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated b...The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO_2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO_2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm^2 for phosphmolybdic acid and 22.81 m W/cm^2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.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
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 heterogeneous catalyst for ultrasound-assisted oxidative desulfurization(UAODS)was designed and synthesized by confining polyoxometalates(POMs)clusters within porous metal-organic gel.The catalyst microstructu...A novel heterogeneous catalyst for ultrasound-assisted oxidative desulfurization(UAODS)was designed and synthesized by confining polyoxometalates(POMs)clusters within porous metal-organic gel.The catalyst microstructures were characterized by XRD,SEM-EDX,FT-IR,N_(2)adsorption-desorption,and XPS.Effects of POM loading,catalyst dosage,and ultrasonic power were also investigated.Results indicate that 60%-PMA@MOX(Al)exhibits optimal catalytic activity,with a sulfur removal rate of 98.61%and excellent reusability.Moreover,a kinetic study of different desulfurization approaches demonstrates that the unique thermal and cavitation effects of ultrasound can effectively improve the efficiency of oxidative desulfurization.展开更多
A highly efficient catalyst of graphene-supported mixed-valent Mn_(16)-containing polyoxometalate is reported here by electrochemical strategy. The modified electrode with the catalyst exhibits an excellent electrocat...A highly efficient catalyst of graphene-supported mixed-valent Mn_(16)-containing polyoxometalate is reported here by electrochemical strategy. The modified electrode with the catalyst exhibits an excellent electrocatalytic performance for water oxidation, which will contribute to the development of highly efficient catalysts for oxygen evolution.展开更多
Bimetallic oxides are attractive anode materials for lithium-ion batteries(LIBs)due to their large theoretical capacity.However,the low conductivity,short cycle life,and poor rate capability are the bottlenecks for th...Bimetallic oxides are attractive anode materials for lithium-ion batteries(LIBs)due to their large theoretical capacity.However,the low conductivity,short cycle life,and poor rate capability are the bottlenecks for their further applications.To overcome above issues,the basket-like polymolybdate(NiP_(6)Mo_(18))and carbon nanotubes(CNTs)were uniformly embedded on the urchin-shaped CoNiO_(2)nanospheres to yield a ternary composites CoNiO_(2)@NiP_(6)Mo_(18)/CNTs via electrostatic adsorption.The multi-level morphology of urchin spinules accelerates the diffusion rate of Li^(+);CNT improves the conductivity and enhances cycle stability of the material;and heteropoly acid contributes more redox activity centres.Thus,CoNiO_(2)@NiP_(6)Mo_(18)/CNTs as an anode of LIBs exhibits a high initial capacity(1396.7 mA h g^(−1)at 0.1 A g^(−1)),long-term cycling stability(750.2 mA h g^(−1)after 300 cycles),and rate performance(450.3 mA h g^(−1)at 2 A g^(−1)),which are superior to reported metallic oxides anode of LIBs.The density functional theory(DFT)and kinetic mechanism suggest that CoNiO_(2)@NiP_(6)Mo_(18)/CNTs delivers an outstanding pseudocapacitance and rapid Li^(+)diffusion behaviors,which is due to the rich surface area of the urchin-like CoNiO_(2)with the uniform embeddedness of NiP_(6)Mo_(18)and CNTs.This study provides a new idea for optimizing the performance of bimetallic oxides and developing high-rate lithium-ion battery composites.展开更多
Deep eutectic solvents(DESs) are a new class of green solvents analogous to ionic liquids due to their biodegradable capacity and low cost. However, the direct extractive desulfurization of diesel oil by DESs cannot m...Deep eutectic solvents(DESs) are a new class of green solvents analogous to ionic liquids due to their biodegradable capacity and low cost. However, the direct extractive desulfurization of diesel oil by DESs cannot meet the government’s standard. In this work, amphiphilic polyoxometalates were synthesized and characterized by FT-IR and mass spectrometry.The oxidative desulfurization results showed that benzothiophene(BT) could be completely removed by employing a [(CH)P(CH)]PMoO, DES(ChCl/2 Ac) and HOsystem. It was also found that the organic cation of catalysts played a positive role in oxidative desulfurization. The reaction conditions, such as reaction temperature and time, the amount of catalyst and DES and HO/S(O/S) molar ratio, were optimized. Different sulfides were tested to determine the desulfurization selectivity of the optimal reaction system, and it was found that 97.2% of dibenzothiophene(DBT) could be removed followed by 80.7% of 4-MDBT and 76.0% of 4,6-DMDBT. After reaction, the IR spectra showed that the catalyst [(CH)P(CH)]PMoOwas stable during the reaction process and the oxidative product was dibenzothiophene sulfone(DBTO). Furthermore, the catalyst can be regenerated and recycled for four runs with little loss of activity.展开更多
Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed...Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.展开更多
The title compound [Ni（DMF）6]3[PMo12O40]2（DIE = N,N＇-dimethyllformamide） was synthesized and structurally characterized by elemental analysis, IR, UV and single crystal X-ray diffraction. It crystallized in the t...The title compound [Ni（DMF）6]3[PMo12O40]2（DIE = N,N＇-dimethyllformamide） was synthesized and structurally characterized by elemental analysis, IR, UV and single crystal X-ray diffraction. It crystallized in the trigonal system, space group R-3, a = 1.591 7（2） nm, b = 1.591 7（2） nm, c = 3.226 9（7） nm, α = 90.00^＊, β=90.00^＊, γ= 120.00^＊, V=7.080（2） nm^3, Z=3 and R1 =0.083 7. It consists of two Keggin polyoxometalates [PMo12O40]3- linked together with three [Ni（DMF）6]^2＋ cations through hydrogen bonding interaction.展开更多
Lithium-sulfur(Li-S) battery is regarded as one of the most fascinating candidates for energy storage due to its dominant advantage of high energy density.However,the shuttling effect of soluble polysulfides and low e...Lithium-sulfur(Li-S) battery is regarded as one of the most fascinating candidates for energy storage due to its dominant advantage of high energy density.However,the shuttling effect of soluble polysulfides and low electrical conductivity of sulfur and Li_(2)S still hinder its commercialization.In this work,high electrical-conductive carbon nanofibers(CNFs) with uniformly embedded polytungstates(HPW@CNFs) are proposed for advanced Li-S batteries.H_(3)PW_(12)O_(40)(HPW) is a kind of molecular nano-sized metal cluster which contains rich Lewis acid/base sites that can stabilize polysulfide effectively through chemical bonding,while CNFs play the role of physical barriers for polysulfides and transmission channel for electrons.The HPW@CNFs/S cathode shows an ultra-stable cycling performance with extremely small decay rate of 0.015% per cycle over 400 cycles at 0.5 C.展开更多
Supported ionic liquid(IL) catalysts [Cmim]PMoO/Am TiO(amorphous TiO) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR...Supported ionic liquid(IL) catalysts [Cmim]PMoO/Am TiO(amorphous TiO) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR, DRS,wide-angle XRD, Nadsorption–desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC–MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [Cmim]PMoO/Am TiOonly dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application.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financially supported by the National Nature Science Foundation of China (Nos. 21776116, 21576122, 21722604)Postdoctoral Foundation of China (No. 2017M621646)+1 种基金Postdoctoral Foundation of Jiangsu Province (No. 2018K083C)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘With the aim of deep desulfurization, silica-supported polyoxometalate-based ionic liquids were successfully prepared by a one-pot hydrothermal process and employed in heterogeneous oxidative desulfurization of various sulfur compounds. The compositions and structures of the hybrid samples were characterized by various methods such as FT-IR, XPS, Raman,UV–Vis, wide-angle XRD and N2adsorption–desorption. The experimental results indicated that the hybrid materials presented a high dispersion of tungsten species and excellent catalytic activity for the removal of 4,6-dimethyldibenzothiophene without any organic solvent as extractant, and the sulfur removal could reach 100.0% under mild conditions.The catalytic performance on various substrates was also investigated in detail. After cycling seven cycles, the sulfur removal of the heterogeneous system still reached 93.0%. The GC-MS analysis results demonstrated that the sulfur compound was first adsorbed by the catalyst and subsequently oxidized to its corresponding sulfone.
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the National Nature Science Foundation of China(No.51077013,50873026)Production and Research Prospective Joint Project of Jiangsu Province of China(BY2009153)+2 种基金the Key Program for the Scientific Research Guiding Fund of Basic Scientific Research Operation Expenditure,Southeast University(3207040103)333 High-level Talent Training Project,Jiangsu Province of China (BRA2010033)Student Research Training Program of Southeast University(No.091028644) for financial support
文摘Aiming at deep desulfurization of gasoline,three amphiphilic catalysts [C18H37N(CH3)3]3+x [PMo12-xVxO40](x=1,2,or 3) were prepared and characterized.The amphiphilic vanadium(V)-substituted polyoxometalates were dissolved in water-immiscible ionic liquid([Bmim]PF6),forming a H2O2-in-[Bmim]PF6 emulsion desulfurization system with 30 m% H2O2 serving as the oxidant.The catalytic oxidation of sulfur-containing model oil has been studied in detail under various reaction conditions using this system.The ionic liquid emulsion system showed high catalytic oxidative activity in the treatment of commodity gasoline.Furthermore,the mechanism of catalytic oxidative desulfurization was also elaborated.
文摘The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO_2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO_2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm^2 for phosphmolybdic acid and 22.81 m W/cm^2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.
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.
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the Project of Jilin Provincial Department of Education (JJKH20190827KJ)the Outstanding Young Talents Fund Project of Jilin Provincial Department of Science and Technology (20190103117JH) for financially support
文摘A novel heterogeneous catalyst for ultrasound-assisted oxidative desulfurization(UAODS)was designed and synthesized by confining polyoxometalates(POMs)clusters within porous metal-organic gel.The catalyst microstructures were characterized by XRD,SEM-EDX,FT-IR,N_(2)adsorption-desorption,and XPS.Effects of POM loading,catalyst dosage,and ultrasonic power were also investigated.Results indicate that 60%-PMA@MOX(Al)exhibits optimal catalytic activity,with a sulfur removal rate of 98.61%and excellent reusability.Moreover,a kinetic study of different desulfurization approaches demonstrates that the unique thermal and cavitation effects of ultrasound can effectively improve the efficiency of oxidative desulfurization.
基金supported by the National Natural Science Foundation of China(No.21371173,51402298,91545125)the China Postdoctoral Foundation(No.2014M550846)
文摘A highly efficient catalyst of graphene-supported mixed-valent Mn_(16)-containing polyoxometalate is reported here by electrochemical strategy. The modified electrode with the catalyst exhibits an excellent electrocatalytic performance for water oxidation, which will contribute to the development of highly efficient catalysts for oxygen evolution.
基金supported by the National Science Foundation of China(22171061,21771046,and 22272143)the 2020 Central Government's Plan to Support the Talent Training Project of the Reform and Development Fund of Local Universities(2020GSP03)+1 种基金the Natural Science Foundation of Heilongjiang Province of China(ZD2021B002)the Fundamental Research Funds for the Central Universities(20720220009).
文摘Bimetallic oxides are attractive anode materials for lithium-ion batteries(LIBs)due to their large theoretical capacity.However,the low conductivity,short cycle life,and poor rate capability are the bottlenecks for their further applications.To overcome above issues,the basket-like polymolybdate(NiP_(6)Mo_(18))and carbon nanotubes(CNTs)were uniformly embedded on the urchin-shaped CoNiO_(2)nanospheres to yield a ternary composites CoNiO_(2)@NiP_(6)Mo_(18)/CNTs via electrostatic adsorption.The multi-level morphology of urchin spinules accelerates the diffusion rate of Li^(+);CNT improves the conductivity and enhances cycle stability of the material;and heteropoly acid contributes more redox activity centres.Thus,CoNiO_(2)@NiP_(6)Mo_(18)/CNTs as an anode of LIBs exhibits a high initial capacity(1396.7 mA h g^(−1)at 0.1 A g^(−1)),long-term cycling stability(750.2 mA h g^(−1)after 300 cycles),and rate performance(450.3 mA h g^(−1)at 2 A g^(−1)),which are superior to reported metallic oxides anode of LIBs.The density functional theory(DFT)and kinetic mechanism suggest that CoNiO_(2)@NiP_(6)Mo_(18)/CNTs delivers an outstanding pseudocapacitance and rapid Li^(+)diffusion behaviors,which is due to the rich surface area of the urchin-like CoNiO_(2)with the uniform embeddedness of NiP_(6)Mo_(18)and CNTs.This study provides a new idea for optimizing the performance of bimetallic oxides and developing high-rate lithium-ion battery composites.
基金financially supported by the National Natural Science Foundation of China (Nos. 21506080 and 21766007)Natural Science Foundation of Jiangsu Province (No. BK20150485)+1 种基金Advanced Talents of Jiangsu University (No. 15JDG053)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Deep eutectic solvents(DESs) are a new class of green solvents analogous to ionic liquids due to their biodegradable capacity and low cost. However, the direct extractive desulfurization of diesel oil by DESs cannot meet the government’s standard. In this work, amphiphilic polyoxometalates were synthesized and characterized by FT-IR and mass spectrometry.The oxidative desulfurization results showed that benzothiophene(BT) could be completely removed by employing a [(CH)P(CH)]PMoO, DES(ChCl/2 Ac) and HOsystem. It was also found that the organic cation of catalysts played a positive role in oxidative desulfurization. The reaction conditions, such as reaction temperature and time, the amount of catalyst and DES and HO/S(O/S) molar ratio, were optimized. Different sulfides were tested to determine the desulfurization selectivity of the optimal reaction system, and it was found that 97.2% of dibenzothiophene(DBT) could be removed followed by 80.7% of 4-MDBT and 76.0% of 4,6-DMDBT. After reaction, the IR spectra showed that the catalyst [(CH)P(CH)]PMoOwas stable during the reaction process and the oxidative product was dibenzothiophene sulfone(DBTO). Furthermore, the catalyst can be regenerated and recycled for four runs with little loss of activity.
文摘Ammonium salts, （NH4）6HPMo11MO40 （M = Ni, Co, Fe）, have been investigated for the oxidation of propane, with molecular oxygen, at temperature ranging between 380 ℃ and 420 ℃ after in-situ pre-treatment performed at two heating rate of 5 or 9 ℃/min. They were characterized by BET method, XRD, 31p NMR, UV-Vis and IR techniques. The catalysts were found active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-treated with the heating rate of 9 ℃/min.
文摘The title compound [Ni（DMF）6]3[PMo12O40]2（DIE = N,N＇-dimethyllformamide） was synthesized and structurally characterized by elemental analysis, IR, UV and single crystal X-ray diffraction. It crystallized in the trigonal system, space group R-3, a = 1.591 7（2） nm, b = 1.591 7（2） nm, c = 3.226 9（7） nm, α = 90.00^＊, β=90.00^＊, γ= 120.00^＊, V=7.080（2） nm^3, Z=3 and R1 =0.083 7. It consists of two Keggin polyoxometalates [PMo12O40]3- linked together with three [Ni（DMF）6]^2＋ cations through hydrogen bonding interaction.
基金financially supported by the National Natural Science Foundation of China(Grant No.51874360)the Program of Huxiang Young Talents(Grant No.2019RS2002)+1 种基金the Innovation-Driven Project of Central South University(2020CX027)the Recruitment Program of Global Youth Experts。
文摘Lithium-sulfur(Li-S) battery is regarded as one of the most fascinating candidates for energy storage due to its dominant advantage of high energy density.However,the shuttling effect of soluble polysulfides and low electrical conductivity of sulfur and Li_(2)S still hinder its commercialization.In this work,high electrical-conductive carbon nanofibers(CNFs) with uniformly embedded polytungstates(HPW@CNFs) are proposed for advanced Li-S batteries.H_(3)PW_(12)O_(40)(HPW) is a kind of molecular nano-sized metal cluster which contains rich Lewis acid/base sites that can stabilize polysulfide effectively through chemical bonding,while CNFs play the role of physical barriers for polysulfides and transmission channel for electrons.The HPW@CNFs/S cathode shows an ultra-stable cycling performance with extremely small decay rate of 0.015% per cycle over 400 cycles at 0.5 C.
基金financially supported by the National Natural Science Foundation of China (Nos. 21576122, 21646001, 21506080)Natural Science Foundation of Jiangsu Province (Nos. BK20150485, BK20170528)+2 种基金China Postdoctoral Science Foundation (2017M611727)Jiangsu Planned Projects for Postdoctoral Research Funds (1701104B)supported by the Student Innovation and Entrepreneurship Training Program (201810299332 W)
文摘Supported ionic liquid(IL) catalysts [Cmim]PMoO/Am TiO(amorphous TiO) were synthesized through a one-step method for extraction coupled catalytic oxidative desulfurization(ECODS) system. Characterizations such as FTIR, DRS,wide-angle XRD, Nadsorption–desorption and XPS were applied to analyze the morphology and Keggin structure of the catalysts. In ECODS with hydrogen peroxide as the oxidant, it was found that ILs with longer alkyl chains in the cationic moiety had a better effect on the removal of dibenzothiophene. The desulfurization could reach 100% under optimal conditions, and GC–MS analysis was employed to detect the oxidized product after the reaction. Factors affecting the desulfurization efficiencies were discussed, and a possible mechanism was proposed. In addition, cyclic experiments were also conducted to investigate the recyclability of the supported catalyst. The catalytic activity of [Cmim]PMoO/Am TiOonly dropped from 100% to 92.9% after ten cycles, demonstrating the good recycling performance of the catalyst and its potential industrial application.
