Performance And Preparation Of Nickel Foam-based Selenide And Nitride As A Bifunctional Photo-electrocatalyst For Efficient Overall Water Splittong

In order to solve the global energy and environmental crisis,photo-electrocatalytic conversion of solar energy into fuel,and the production of hydrogen and oxygen have received increasing attention.In the past few decades,a large number of semiconductor materials have been explored as photocatalysts for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER).But until now,with the increasing demand for catalysts from energy devices,their practical application is still hampered.Therefore,this paper has investigated the preparation and optimization of bifunctional catalysts and the performance of photoelectrolytic hydrogen evolution.In this work,nickel molybdate array(NiMoO4/NF)was prepared on nickel foam by hydrothermal method,and then MoSe2/NixSey nanosheets were recharged by hydrothermal method to prepare nickel molybdate array coated with MoSe2/NixSey nanosheets.Core-shell structure(N1MoO4@MoSe2/NixSey/NF).The addition of the nickel molybdate array greatly increases the contact area between the lamellar structure and the solution,and better exposes the active site of the lamellar structure,accelerates the electron transport efficiency,and improves the performance of electrochemical water decomposition.In 1M KOH solution,-10 mA cm-2 can reach 69mV overpontial under hydrogen evolution conditions.Under oxygen evolution conditions,an overpotential of 290 mV can be reached at 200 mA cm-2.In addition,under the two-electrode system,overall water splitting test was performed,and over-potential of 1.46V was obtained at 20 mA cm-2.Obvious bubbles appeared at the cathode and anode by driving the 1.5 V battery,which proved that NiN4oO4@MoSe2/NixSey/NF sample has the excellent performance of a bifunctional catalyst.In this work,zinc oxide array(ZnO/NF)was prepared by a hydrothermal method on a nickel foam substrate,followed by a nitrogen doping reaction,and N-Doped-ZnO/NF array was prepared by introducing ammonia gas in a tube furnace for thermal insulation.The Ni3N in the product improves the conductivity of the catalyst and its ability to adsorb and desorb gas,and the combination of Ni3N and ZnO improves the photo-electrocatalytic performance of the sample.In 1M KOH alkaline solution,N-Doped-ZnO/NF can reach hydrogen evolution and oxygen evolution potentials of 82mV and 301mV at a current density of 10 mA cm-2 under light.Under dark condition,the N-Doped-ZnO/NF can reach the hydrogen evolution and oxygen evolution potentials at 99 mV and 319 mV at a current density of 10 mA cm-2.And it has a light response of 0.704 mA cm-2 under-0.133V vs RHE bias,which proves that N-Doped-ZnO/NF is a good photo-electrolytic water material.