Crystal-plane-controlled restructuring and enhanced oxygen-involving performances of bifunctional catalyst

Abstract Surface reconstruction phenomenon of substrate induced by strong interactions of heterointerfaces may result in the development of unusual physical and chemical properties. Here we adopt a simple method in which ultrathin Co3O4 nanomeshes (2.6 nm) are synthesized to increase the oxygen release under high temperature, allowing a phase transition for the two cobalt oxide types. With the introduction of S atoms in the conversion process, the exposed crystal plane of CoO changes from (0 1 1 ) to ( 1 11 ) owing to the restrictive effect of in-situ formed CoS thin film, which is the first time to reveal the restructuring of substrate under strong interface interactions of heterostructure. By creating abundant interfaces with subtle lattice distortion in CoS/CoO heterostructure, these special interfaces can be deemed as dominant active sites to accelerate the ORR/OER reaction. The CoS/CoO shows a considerable OER performance with an only 20 mV higher potential than IrO2 at 10 mA cm-2 and decent ORR performances, which realizes a half-wave potential of 0.82 V and high durability. This work may open up a promising way to rationally design hybrid catalysts for efficient and durable application of electrocatalytic devices.