Application Of Nickel Phosphide And Cobaloxime Catalysts For Catalytic Water Oxidation

Electrochemical water splitting into hydrogen and oxygen is a promising strategy for future renewable energy conversion devices.In addition,electrochemical water splitting can be coupled with a solar-electric power conversion to form the photoelectrochemical(PEC)cell,which could enable the direct use of intermittent solar energy with no environmental costs.Oxygen evolution reaction(OER)is considered as the bottleneck reaction in a overall water splitting system because it involves 4e-and 4 H+transfer processes.Many precious metals show high catalytic activities toward water oxidation,however,the scarcity and high cost of noble metals significantly impede their practical application.Therefore,it is highly desired to explore low-cost alternative catalysts for OER at ambient conditions.Our work explore suitable non-noble metal catalyst for water oxidation in electrochemical cell and PEC cell:1.Catalytic activity of Ni2P nanosheets on Fe foam for elctrochemical water oxidation.Nickel phosphide nanosheets can be facilely grown on Fe foam(Ni2P-FF)as an efficient electrocatalyst for OER with excellent durability and catalytic activity under the alkaline conditions.To reach a current density of 10 mA/cm2,the Ni2PrFF catalyst shows a low overpotential of only 198 mV for 24 h during electrolysis.Meanwhile,the high OER activity and durability are well maintained to achieve a high current density.The required overpotentials are only 267 mV and 313 mV to achieve current densities of 100 mA/cm2 and 300 mA/cm2,respectively.The combination of low-cost Fe foam with Ni2P can provide a promising low-cost candidate for large-scale application of electrocatalytic hydrogen production.2.Catalytic activity of Ni-OEC/cobaIoxime/BiVO4 photoanode for PEC water oxidation.For the first time,novel Ni-OEC/cobaloxime/BiVO4 photoanode was fabricated and exhibited excellent activity for PEC water oxidation.The photoanode was constructed by electrodepositing Ni-OEC on the cobaloxime/BiVO4 plate,which was obtained by dropping cobaloxime solution on BiVO4 photoanode.The as-prepared photoanode showed a photocurrent density of 5.1 mA/cm2 on 1.23 V vs.RHE in KBi solution(pH=9)under AM 1.5 G simulated sunlight illumination.Meanwhile,the photocurrent is quite stable during the 70-min potentiostatic measurement.The highly efficient and durable Ni-OEC/cobaloxime/BiVO4 photoanode for PEC water oxidation could be significant for the large-scale application of PEC water splitting.