Over the last decade’s magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as w...Over the last decade’s magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as well as their extraordinary high gravimetric and volumetric storage densities.This review work provides a broad overview of the most appealing systems and of their hydrogenation/dehydrogenation properties.Special emphasis is placed on reviewing the efforts made by the scientific community in improving the material’s thermodynamic and kinetic properties while maintaining a high hydrogen storage capacity.展开更多
Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode...Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts,which are still challenging due to the totally different catalytic mechanisms.Herein,the[W–O]group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst,which possesses excellent catalytic performances towards both HER(185.60 mV at 1000 mA cm^(−2))and HzOR(78.99 mV at 10,00 mA cm^(−2))with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm^(−2).The introduction of[W–O]groups,working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation,leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in[W–O]group as well,resultantly boosting the hydrogen production and HzOR.Moreover,a proof-of-concept direct hydrazine fuel cell-powered H_(2) production system has been assembled,realizing H_(2)evolution at a rate of 3.53 mmol cm^(−2)h^(−1)at room temperature without external electricity supply.展开更多
The reaction kinetics of the oxidative dehydrogenation of propane was studied at 475-550°C over a VMgO catalyst. Vanadium-magnesium-oxides are among the most selective and active catalysts for the dehydrogenation...The reaction kinetics of the oxidative dehydrogenation of propane was studied at 475-550°C over a VMgO catalyst. Vanadium-magnesium-oxides are among the most selective and active catalysts for the dehydrogenation of propane to propylene. Selectivity to propylene up to about 60% was obtained at 10% conversion, but the selectivity decreased with increasing conversion. No oxygenates were detected, the only by-products were CO and CO2. The reaction rate of propane was found to be first order in propane and close to zero order in oxygen, which is in agreement with a Mars van Krevelen mechanism with the activation of the hydrocarbon as the rate determining step. The activation energy of the conversion of propane was found to be 122±6 kJ/mol.展开更多
文摘Over the last decade’s magnesium and magnesium based compounds have been intensively investigated as potential hydrogen storage as well as thermal energy storage materials due to their abundance and availability as well as their extraordinary high gravimetric and volumetric storage densities.This review work provides a broad overview of the most appealing systems and of their hydrogenation/dehydrogenation properties.Special emphasis is placed on reviewing the efforts made by the scientific community in improving the material’s thermodynamic and kinetic properties while maintaining a high hydrogen storage capacity.
基金support of this research by National Natural Science Foundation of China(52172110)Key Research Program of Frontier Sciences,Chinese Academy of Sciences(ZDBS-LY-SLH029)+1 种基金the“Scientific and Technical Innovation Action Plan”Hong Kong,Macao and Taiwan Science&Technology Cooperation Project of Shanghai Science and Technology Committee(21520760500)BL14W1 beamline of Shanghai Synchrotron Radiation Facility(SSRF).
文摘Hydrazine oxidation reaction(HzOR)assisted hydrogen evolution reaction(HER)offers a feasible path for low power consumption to hydrogen production.Unfortunately however,the total electrooxidation of hydrazine in anode and the dissociation kinetics of water in cathode are critically depend on the interaction between the reaction intermediates and surface of catalysts,which are still challenging due to the totally different catalytic mechanisms.Herein,the[W–O]group with strong adsorption capacity is introduced into CoP nanoflakes to fabricate bifunctional catalyst,which possesses excellent catalytic performances towards both HER(185.60 mV at 1000 mA cm^(−2))and HzOR(78.99 mV at 10,00 mA cm^(−2))with the overall electrolyzer potential of 1.634 V lower than that of the water splitting system at 100 mA cm^(−2).The introduction of[W–O]groups,working as the adsorption sites for H2O dissociation and N2H4 dehydrogenation,leads to the formation of porous structure on CoP nanoflakes and regulates the electronic structure of Co through the linked O in[W–O]group as well,resultantly boosting the hydrogen production and HzOR.Moreover,a proof-of-concept direct hydrazine fuel cell-powered H_(2) production system has been assembled,realizing H_(2)evolution at a rate of 3.53 mmol cm^(−2)h^(−1)at room temperature without external electricity supply.
文摘The reaction kinetics of the oxidative dehydrogenation of propane was studied at 475-550°C over a VMgO catalyst. Vanadium-magnesium-oxides are among the most selective and active catalysts for the dehydrogenation of propane to propylene. Selectivity to propylene up to about 60% was obtained at 10% conversion, but the selectivity decreased with increasing conversion. No oxygenates were detected, the only by-products were CO and CO2. The reaction rate of propane was found to be first order in propane and close to zero order in oxygen, which is in agreement with a Mars van Krevelen mechanism with the activation of the hydrocarbon as the rate determining step. The activation energy of the conversion of propane was found to be 122±6 kJ/mol.
基金This work was supported by the National Natural Science Foundation of China(No.12075243)the National Key Research and Development Program of China(No.2017YFA0402800)。
