本研究采用水热-磷化-电化学沉积法在磷化钴表面构筑了金属氢氧化物层,制备了NiFeOH/CoP/NF复合电极,考察了复合电极电解水制氢的性能.在 1.0 mol◌ ּ/L的KOH介质中,NiFeOH/CoP/NF复合电极表现出良好的催化电解水性能.在电流密度为 100 mA/cm2 时,NiFeOH/CoP/NF复合电极电催化析氢(HER)和析氧反应(OER)所需的过电势分别为 141 和 372 mV.在电流密度为 10 mA/cm2 时,NiFeOH/CoP/NF同时用作阴极和阳极电解水所需电压仅为 1.61 V.NiFeOH保护层增强了CoP在电解水反应中的活性和稳定性,NiFeOH/CoP/NF复合电极在恒电流电解中表现出高的 HER 和 OER 稳定性,活性可维持 60000 s,性能未见明显衰减.将 NiFeOH/CoP/NF 两电极电解池与GaAs 太阳能电池组成光伏-电解水系统,该系统在 100 mW/cm2 模拟光照条件下,太阳能至氢能转化效率达到18.0%,并可稳定运行 200 h.
Electrocatalytic Water Splitting over Nickel Iron Hydroxide-cobalt Phosphide Composite Electrode
NiFeOH/CoP/NF composite electrode was fabricated by constructing a metal hydroxide layer on the surface of cobalt phosphide via hydrothermal,phosphating,and electrodeposition methods.The electrolytic water splitting to hydrogen performance by as-prepared electrode was investigated in 1.0 mol/L KOH medium.NiFeOH/CoP/NF composite electrode exhibited excellent water electrolysis performance,and the required overpotentials for HER and OER at 100 mA/cm2 current density were 141 and 372 mV,respectively.When NiFeOH/CoP/NF electrode served as both cathode and anode for water splitting,only 1.61 V voltage was required to reach current density of 10 mA/cm2.Because NiFeOH protection layer enhanced the electrocatalytic activity and stability of CoP for water splitting,NiFeOH/CoP/NF composite electrode exhibited high stability during the galvanostatic electrolysis in the HER and OER,and its activity could maintain 60000 s without significant performance degradation.The photovoltaic-electrolytic water cell constructed with two NiFeOH/CoP/NF electrodes and GaAs solar cell showed 18.0%efficiency of solar to hydrogen under 100 mW/cm2 simulated solar irradiation and worked stably for 200 h.
cobalt phosphidemetal hydroxide protection layerelectrocatalytic water splittingstability
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