Bimetallic two-dimensional materials for electrocatalytic oxygen evolution

Electrocatalytic oxygen evolution reaction (OER) is one of the important half reactions of electrocatalytic water splitting. However, the slow kinetic process involving four-electron transfer severely limits its reaction efficiency, which in turn limits the overall electrocatalytic hydrolysis efficiency. In order to improve the activity of the electrocatalytic OER, researchers mainly update the catalyst from three aspects, that is, increase the conductivity of the electrocatalyst, and the quantity and quality of active sites. Two-dimensional (2D) engineering can effectively reduce the resistance of the materials and greatly increase the number of electrochemically active sites, while heterometal doping, or the bimetal strategy, can improve the quality of active sites via changing the electronic structure of the material. Thus, the combination of the two can enhance the activity of electrocatalytic OER in all three aspects: conductivity, number and quality of active sites. However, there is currently no review on this topic. Therefore, in this review, we summarize the application of bimetallic 2D materials in electrocatalytic OER from four aspects: the structure, synthesis strategy, catalytic efficiency, and reaction mechanism.