Design Of Interface-coupled And Doped Nickel-based Catalysts For Electrocatalytic Oxygen Evolution

Water splitting that produces H₂ has been considered as one of effective ways to meet future global energy demands.In the process of electrocatalytic water splitting,OER is a multi-step electron transfer process,and an efficient electrocatalyst is required to improve the driving force of the reaction.Ni-based materials as unexpensive and efficient earth-abundant catalysts have showed excellent catalytic activity for OER.Construction of heterogeneous interfaces is one of the effective methods to improve the catalytic activity of catalysts.In general,Heterostructures catalysts with abundant interfaces as active sites will facilitate charge separation and electron transfer during the reaction,which play an important role on improving electrocatalytic activity.In addition,doping heteroatoms can be used to change the chemical environment around the active metal species to adjust the electronic structure and surface electronic state to promote catalytic activity.In addition,co-doping of multiple element atoms generally has excellent OER catalytic performance than single-atom doping.And studies have shown that the catalytic activity of some amorphous or partially amorphous catalysts is better than that of crystalline catalysts.Therefore,the preparation of amorphous multiple doped materials as catalysts is a method to improve catalyst activity.In this paper,nickel-based catalytic materials are used as targets.By constructing heterogeneous interface structures and amorphous multiple doping strategies,the electrocatalytic oxygen evolution performance can be efficiently controlled.The specific research methods and contents are as follows:?1?Nickel oxide?NiO?nanoclusters supported on chromium oxide?Cr₂O₃?nanosheets were synthesized by a two-step synthesis method to form a new type of NiO-Cr₂O₃ heterostructure,which can be used as an effective catalyst for OER.Compared with pure Ni O and Cr₂O₃,NiO-Cr₂O₃ has higher OER activity,a smaller overpotential of 270 mV,a lower Tafel slope and stability under alkaline conditions.X-ray photoelectron spectroscopy,in-situ Raman spectroscopy,and theoretical calculations revealed the reason for the high catalytic activity of NiO-Cr₂O₃.The results show that the active site of NiO-Cr₂O₃ is on the Cr-Ni interface.Due to the charge transfer between the Cr and Ni atoms at the interface,the change in the electronic structure of Cr and Ni reduces the adsorption energy of oxygen and increases its catalytic activity.This work builds a new Cr-Ni interface coupling method through NiO-Cr₂O₃ heterostructure,which provides a new strategy for designing new efficient and inexpensive OER catalysts.?2?Nickel nanoalloys are potential low-cost OER electrocatalysts,but their catalytic activity and stability need to be improved.The use of an anionic element with a partially amorphous nickel catalyst can improve its electrocatalytic activity.The ternary B,P and O doped amorphous nickel nano-alloys?BPO-Ni?were prepared for OER catalysis studies.Compared with binary boron-oxygen-doped nickel?BO-Ni?and phosphorus-oxygen-doped nickel?PO-Ni?,ternary BPO-Ni has higher OER catalytic activity and better stability performance under alkaline conditions.The results show that the high catalytic activity of B,P,and O-doped Ni nanoalloys originates from the synergistic effect between ternary heteroatoms and Ni atoms.This work resulted in a new non-metal-doped amorphous nickel nanoalloy structure and provided a method for investigating new,cheap and efficient OER catalysts.