Combining urea oxidation reaction(UOR) with hydrogen evolution reaction(HER) is an effective method for energy saving and highly efficient electrocatalytic hydrogen production. Herein, molybdenumincorporated cobalt ca...Combining urea oxidation reaction(UOR) with hydrogen evolution reaction(HER) is an effective method for energy saving and highly efficient electrocatalytic hydrogen production. Herein, molybdenumincorporated cobalt carbonate hydroxide nanoarrays(CoxMoyCH) are designed and synthesized as a bifunctional catalyst towards UOR and HER. Benefiting from the Mo doping, the dispersed nanoarray structure and redistributed electron density, the CoxMoyCH catalyst display outstanding catalytic performance and durability for both HER and UOR, affording the overpotential of 82 m V for HER and delivering a low potential of the 1.33 V for UOR(vs. reversible hydrogen electrode, RHE) to attain a current density of 10 m A cm^(-2), respectively. Remarkably, when CoxMoyCH was applied as bifunctional catalyst in a twoelectrode electrolyzer, a working voltage of 1.40 V is needed in urea-assisted water electrolysis at10 m A cm^(-2) and without apparent decline for 40 h, outperforming the working voltage of 1.51 V in conventional water electrolysis.展开更多
To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with...To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.展开更多
基金financially supported by the National Natural Science Foundation of China(52025013,22121005)the 111 Project(B12015)+1 种基金Haihe Laboratory of Sustainable Chemical Transformationsthe Fundamental Research Funds for the Central Universities。
文摘Combining urea oxidation reaction(UOR) with hydrogen evolution reaction(HER) is an effective method for energy saving and highly efficient electrocatalytic hydrogen production. Herein, molybdenumincorporated cobalt carbonate hydroxide nanoarrays(CoxMoyCH) are designed and synthesized as a bifunctional catalyst towards UOR and HER. Benefiting from the Mo doping, the dispersed nanoarray structure and redistributed electron density, the CoxMoyCH catalyst display outstanding catalytic performance and durability for both HER and UOR, affording the overpotential of 82 m V for HER and delivering a low potential of the 1.33 V for UOR(vs. reversible hydrogen electrode, RHE) to attain a current density of 10 m A cm^(-2), respectively. Remarkably, when CoxMoyCH was applied as bifunctional catalyst in a twoelectrode electrolyzer, a working voltage of 1.40 V is needed in urea-assisted water electrolysis at10 m A cm^(-2) and without apparent decline for 40 h, outperforming the working voltage of 1.51 V in conventional water electrolysis.
基金This work was financially supported by the National Natural Science Foundations of China(21878061).
文摘To achieve high efficiency of water electrolysis to produce hydrogen(H_(2)),developing non-noble metal-based catalysts with consid-erable performance have been considered as a crucial strategy,which is correlated with both the interphase properties and multi-metal synergistic effects.Herein,as a proof of concept,a delicate NiCo(OH)_(x)-CoyW catalyst with a bush-like heterostructure was realized via gas-template-assisted electrodeposition,followed by an electrochemical etching-growth process,which ensured a high active area and fast gas release kinetics for a superior hydrogen evolution reaction,with an overpotential of 21 and 139 mV at 10 and 500 mA cm^(−2),respectively.Physical and electrochemical analyses demonstrated that the synergistic effect of the NiCo(OH)_(x)-Co_(y)W heteroge-neous interface resulted in favorable electron redistribution and faster electron transfer efficiency.The amorphous NiCo(OH)_(x) strengthened the water dissociation step,and metal phase of CoW provided sufficient sites for moderate H immediate adsorption/H_(2) desorption.In addition,NiCo(OH)_(x)-CoyW exhibited desirable urea oxidation reaction activity for matching H_(2) generation with a low voltage of 1.51 V at 50 mA cm^(−2).More importantly,the synthesis and testing of the NiCo(OH)_(x)-CoyW catalyst in this study were all solar-powered,sug-gesting a promising environmentally friendly process for practical applications.
