Electrocatalytic Hydrogen Evolution Coupled To Benzylamine Oxidation Over Ni-based Bimetallic Nitride

The energy crisis and environmental problems related to extreme climate promote the vigorous development of sustainable energy.Electrocatalytic water splitting has received widespread attention due to its power provided by sustainable energy sources such as solar and wind energy.The water splitting process is divided into two parts:the oxygen evolution reaction(OER)at the anode and the hydrogen evolution reaction(HER)at the cathode.The larger energy barrier of OER reduces the hydrogen evolution efficiency.Recently,a promising approach is to use reactive oxygen species(Oads)generated by water splitting in low alkaline medium to oxidize organic compounds instead of OER,forming a synergistic electrocatalytic system with HER to generate value-added chemicals while achieving more energy-efficient hydrogen(H2)production.Therefore,a HER coupled benzylamine electrooxidation(BAOR)system can be constructed in a low alkaline medium using inexpensive and readily available catalysts such as Ni-Mo(Mn)to generate the value-added product benzonitrile(BN)while reducing the energy consumption of cathode hydrogen production.Based on the above research status,this article designed and completed the construction of Ni-Mn nitride and Ni-Mo nitride heterojunction materials,and conducted in-depth research on the HER coupling BAOR performance of the two catalytic materials.Firstly,a series of tests have confirmed that the Ni3N-MnO/NF heterojunction can achieve HER coupling BAOR in low alkaline medium.The subsequent construction of the Mo0.8Ni0.2N-Ni3N/NF heterojunction further improved the catalytic performance of the coupling system,successfully achieving high Faraday efficiency production of H2 and BN in low alkaline media under industrial related current density.Therefore,this article delves into the mechanism of HER and BAOR of Mo0.8Ni0.2N-Ni3N/NF:the charge transfer from Ni3N to Mo0.8Ni0.2N in heterojunctions leads to an upward shift of the d-band center,which is conducive to the adsorption of H*and OH*species from water.On the one hand,it is beneficial to reduce the activation energy of water,optimize the adsorption of H*at the Ni site in the heterojunction Mo0.8Ni0.2N,and promote HER;On the other hand,it helps to more easily generate and adsorb OH*species from water,thereby forming NiOOH active species at Ni sites in heterojunction Ni3N and optimizing the adsorption energy of BA,effectively catalyzing BAOR.Therefore,the system can achieve an industrial current density of 220 mA cm-2 in a low alkaline medium at 1.59 V,and the Faraday efficiency of the coupling system for producing H2 and converting BA to BN is greater than 99%.These two works in this article provide guidance for regulating the adsorption behavior of active substances through interface engineering in low alkaline systems and designing bifunctional electrocatalysts for hybrid water splitting systems with industrial related current densities.