The single phase La2（CO3）3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2（CO3）3·3.4H2O from 30 to 1000 °C were characteri...The single phase La2（CO3）3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2（CO3）3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2（CO3）3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2（CO3）3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction（FnFnFn model）. The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.展开更多
Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is cons...Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is constructed by reversible metal electrodeposition(RME)of Bi/Cu on WO_(3)·xH_(2)O film electrodeposited onto fluorine-doped tin oxide(FTO)transparent conductive glass.The electrolyte consists of CuCl_(2),BiCl_(3),KCl and HCl aqueous solution,supplying necessary components for both electrochemical and electrodeposition processes.The ECD shows ability to rapidly transition between colorless and black states,which achieves a large optical modulation of 77.0%at 570 nm.In the black state,the ECD exhibits a near-zero transmittance in the wavelength range of 400-1100 nm while maintaining 96.6%of its initial optical modulation after coloration/bleaching cycling of 60000 s,exhibiting good cyclic stability.This RMED has relatively high stability under open-circuit voltage and also possesses excellent heat insulation performance.The results offer a solution to overcome the poor cyclic stability of RMEDs and improve the optical modulation of ECDs.展开更多
The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contribu...The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contributing to addressing sustainability challenges.The S-scheme charge transfer mechanism enhances charge separation by maintaining strong redox potentials at both ends,facilitating both oxidation and reduction reactions.Herein,we synthesize a visible-light-responsive oxygen vacancy-rich In_(2)O_(3-x)/tubular carbon nitride(IO_(OV)/TCN)S-scheme heterojunction photocatalyst via electrostatic adherence for selec-tive 5-hydroxymethylfurfural(HMF)oxidation to 2,5-diformylfuran(DFF)and 2,5-furandicarboxylic acid(FDCA),alongside H_(2)production.Under anaerobic conditions and visible-light irradiation,the optimal IOOV/TCN-10 catalyst achieves an HMF conversion of 94.8%with a selectivity of 53.6%for DFF and FDCA,and a H_(2)yield of 754.05μmol g^(−1)in 3 h.The significantly improved photocatalytic activity results from enhanced visible-light absorption,reduced carrier recombination,and abundant catalytic active sites due to the synergistic effect of surface oxygen vacancies,the hollow nanotube-based architecture,and the S-scheme charge transfer mechanism.This work highlights the great potentials of S-scheme heterojunctions in biomass conversion for sustainable energy use and chemical production.展开更多
The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,...The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,the Mg^(2+)/La^(3+)electrodeposition on the tungsten(W)electrode at 973 K was found to be a one-step process.The nucleation of metal ions on the electrode surface followed an instantaneous nucleation mode and was not influenced by the alloying process.The redox potential and underpotential deposition behavior of the metal ions in the NKML system were accurately predicted by the DPMD simulations,confirming the alloying process of the Mg-La.Additionally,scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)analysis results confirmed that the cathodic deposits consisted of a bright phase and a dark phase,corresponding to the Mg-La alloys and Mg,respectively.The distribution of electrolytic products suggests that the cathodic deposit initially favors the Mg phase,with the Mg-La alloy forming more easily when the Mg source in the melt is depleted.展开更多
La2O2CO3 was prepared by calcination of La2 （CO3）3 in the air. Catalysts Ni-Fe/La2O2CO3 with different mole ratios of Ni to Fe, Ni/La2O2CO3 and Fe/La2O2CO3 were prepared by impregnation method. The catalytic propert...La2O2CO3 was prepared by calcination of La2 （CO3）3 in the air. Catalysts Ni-Fe/La2O2CO3 with different mole ratios of Ni to Fe, Ni/La2O2CO3 and Fe/La2O2CO3 were prepared by impregnation method. The catalytic properties were evaluated on steam reforming of ethanol （SRE） from 300 to 700 ℃ under atmospheric pressure and the samples were characterized by Brunauer-Emmett-Teller method （BET）, X-ray diffraction （XRD） and temperature programmed reduction （TPR）. The results showed that Ni-Fe bimetallic catalysts exhibited higher activities than single metallic catalysts, which was attributed to the co-existence of well dispersed Ni, Fe and LaFeyNi1-yO3. It was found that the catalyst Ni-Fe/La2O2CO3 containing 10 wt.% Ni and 3 wt.%-5 wt.% Fe showed the best performance, the conversion of ethanol was 100%, the selectivity of H2 was higher than 90%, and the selectivity of CO was lower than 1.5% at 400 ℃.展开更多
基金Project(201011005-5)supported by the National Land and Resources Public Welfare Scientific Research Project of ChinaProject(41030426)supported by the National Natural Science Foundation of China+1 种基金Project(20095122110015)supported by Specialized Research Fund for the Doctoral Program of Higher Education of ChinaProject(2010-32)supported by Scientific Research Foundation of the Education Ministry for Returned Chinese Scholars,China
文摘The single phase La2（CO3）3·3.4H2 O was synthesized by hydrothermal method. The thermal decomposition and intermediates and final solid products of La2（CO3）3·3.4H2O from 30 to 1000 °C were characterized by XRD, FTIR and DTA-TG. The kinetics of dehydration of La2（CO3）3·3.4H2O in the temperature range of 30-366 °C was investigated under non-isothermal conditions. Flynn-Wall-Ozawa and Friedman isoconversion methods were used to calculate the activation energy and analyze the reaction steps; multivariate non-linear regression program was applied to determine the most probable mechanism and the kinetic parameters. The results show that the thermal dehydration of La2（CO3）3·3.4H2O is a kind of three-step competitive reaction, and controlled by an n-order initial reaction followed by n-order competitive reaction（FnFnFn model）. The activation energy matching with the most probable model is close to value obtained by Friedman method. The fitting curves match the original TG-DTG curves very well.
文摘Electrochromic(EC)smart windows utilizing a reversible metal electrodeposition device(RMED)offer a compelling alternative for dynamically regulating transmissions of optical and thermal energy.An EC device(ECD)is constructed by reversible metal electrodeposition(RME)of Bi/Cu on WO_(3)·xH_(2)O film electrodeposited onto fluorine-doped tin oxide(FTO)transparent conductive glass.The electrolyte consists of CuCl_(2),BiCl_(3),KCl and HCl aqueous solution,supplying necessary components for both electrochemical and electrodeposition processes.The ECD shows ability to rapidly transition between colorless and black states,which achieves a large optical modulation of 77.0%at 570 nm.In the black state,the ECD exhibits a near-zero transmittance in the wavelength range of 400-1100 nm while maintaining 96.6%of its initial optical modulation after coloration/bleaching cycling of 60000 s,exhibiting good cyclic stability.This RMED has relatively high stability under open-circuit voltage and also possesses excellent heat insulation performance.The results offer a solution to overcome the poor cyclic stability of RMEDs and improve the optical modulation of ECDs.
基金financially supported by the Natural Science Foundation of China(Nos.21972058,22102064,and 22302080)Anhui Key Laboratory of Nanomaterials and Nanotechnology,the Major Science and Technology Projects in Anhui Province(No.202305a12020006).
文摘The integration of selective oxidation of renewable biomass and its derivatives with hydrogen(H_(2))pro-duction holds significant potential for simultaneously yielding value-added chemicals and“green H_(2)”,contributing to addressing sustainability challenges.The S-scheme charge transfer mechanism enhances charge separation by maintaining strong redox potentials at both ends,facilitating both oxidation and reduction reactions.Herein,we synthesize a visible-light-responsive oxygen vacancy-rich In_(2)O_(3-x)/tubular carbon nitride(IO_(OV)/TCN)S-scheme heterojunction photocatalyst via electrostatic adherence for selec-tive 5-hydroxymethylfurfural(HMF)oxidation to 2,5-diformylfuran(DFF)and 2,5-furandicarboxylic acid(FDCA),alongside H_(2)production.Under anaerobic conditions and visible-light irradiation,the optimal IOOV/TCN-10 catalyst achieves an HMF conversion of 94.8%with a selectivity of 53.6%for DFF and FDCA,and a H_(2)yield of 754.05μmol g^(−1)in 3 h.The significantly improved photocatalytic activity results from enhanced visible-light absorption,reduced carrier recombination,and abundant catalytic active sites due to the synergistic effect of surface oxygen vacancies,the hollow nanotube-based architecture,and the S-scheme charge transfer mechanism.This work highlights the great potentials of S-scheme heterojunctions in biomass conversion for sustainable energy use and chemical production.
基金support from the National Natural Science Foundation of China(No.U20A20147).
文摘The alloying process of Mg-La in NaCl-KCl-MgCl_(2)-LaCl_(3)(NKML)melts during electroreduction was elucidated using electrochemical techniques and deep potential molecular dynamics(DPMD)simulations.In the NKML system,the Mg^(2+)/La^(3+)electrodeposition on the tungsten(W)electrode at 973 K was found to be a one-step process.The nucleation of metal ions on the electrode surface followed an instantaneous nucleation mode and was not influenced by the alloying process.The redox potential and underpotential deposition behavior of the metal ions in the NKML system were accurately predicted by the DPMD simulations,confirming the alloying process of the Mg-La.Additionally,scanning electron microscopy with energy dispersive spectroscopy(SEM-EDS)analysis results confirmed that the cathodic deposits consisted of a bright phase and a dark phase,corresponding to the Mg-La alloys and Mg,respectively.The distribution of electrolytic products suggests that the cathodic deposit initially favors the Mg phase,with the Mg-La alloy forming more easily when the Mg source in the melt is depleted.
基金Project supported by the National Natural Science Foundation of China (20863006)the Natural Science Foundation of Jiangxi Province (0620042)Department of Education of Jiangxi Province (GJJ09078)
文摘La2O2CO3 was prepared by calcination of La2 （CO3）3 in the air. Catalysts Ni-Fe/La2O2CO3 with different mole ratios of Ni to Fe, Ni/La2O2CO3 and Fe/La2O2CO3 were prepared by impregnation method. The catalytic properties were evaluated on steam reforming of ethanol （SRE） from 300 to 700 ℃ under atmospheric pressure and the samples were characterized by Brunauer-Emmett-Teller method （BET）, X-ray diffraction （XRD） and temperature programmed reduction （TPR）. The results showed that Ni-Fe bimetallic catalysts exhibited higher activities than single metallic catalysts, which was attributed to the co-existence of well dispersed Ni, Fe and LaFeyNi1-yO3. It was found that the catalyst Ni-Fe/La2O2CO3 containing 10 wt.% Ni and 3 wt.%-5 wt.% Fe showed the best performance, the conversion of ethanol was 100%, the selectivity of H2 was higher than 90%, and the selectivity of CO was lower than 1.5% at 400 ℃.
