The development of clean and renewable energy technologies is seen as the key to addressing energy and environmental issues.Oxygen evolution reaction (OER) plays key roles in storage intermittent energy,such as solar and wind,from water splitting.Recently, OER under neutral conditions receives considerable interests due to its environmental friendliness.However,the efficiency of OER under neutral environment is far below that under alkaline or acidic condition.In this review,the current researchers' understanding of the mechanism of OER under mild pH conditions is firstly outlined.Thereafter,several important characterisation techniques for in situ tracking of the electrocatalytic process of OER are presented,which is crucial to reveal the OER mechanism under neutral conditions.Moreover,an overview over catalytic materials towards neutral OER,including Co?,Ni?,and Mn?based catalysts,is provided.Finally,a brief outlook on the remaining challenges and possible strategies for promoting neutral OER is given.

Two?dimensional transition metal carbides and nitrides (MXenes) have become a high?profile material with a wide range of application prospects due to their efficient adsorption and catalytic properties,wide optical absorption range,and excellent conductivity.Ni?doped Nb₂C material has positive photocatalytic properties.To explore the intrinsic mechanism of photocatalytic property improvement by Ni?doped Nb₂C,the electronic structure properties of Nb₂C and its Ni?functionalized form(i.e.,Ni?Nb₂C) and their adsorption properties for CO₂ gas molecule by using the density functional theory (DFT) were investigated.The results show that the replacement of an Nb atom by a Ni atom makes the charge density around the Ni atom increase and further results in a redistribution of the charge density of the substrate,which leads to an improved electronic environment for catalyzing CO₂ and improves the photocatalytic property for CO₂.