Prussian blue analog-derived Co/CoTe microcube as a highly efficient and stable electrocatalyst toward oxygen evolution reaction

In this study, a three-step process involving precipitation, reflux-hydrothermal method, and hydrogen treatment leads to the formation of a Prussian blue analog (PBA)-derived Co/CoTe heterostructure featuring a unique hierarchical 3D structure. This framework facilitates efficient exposure of the catalytically active sites and fast diffusion of the electrolyte. Additionally, the well-defined metal/semiconductor heterointerfaces result in an overall electrical conductivity enhancement and promote the oxygen evolution reaction (OER) kinetics by lowering the activation energy. Owing to the synergistic effect of Co and CoTe, the Co/CoTe heterostructure displays high electrocatalytic activity for OER, attaining an overpotential of 400 mV to deliver a current density of 50 mA cm−2 and a low Tafel slope of 94.1 mV dec−1, which is superior to pure CoTe and Co counterparts. Furthermore, the Co/CoTe exhibits outstanding durability over 50 h without obvious change in alkaline media. The synthetic strategy reported in this paper provides new insights into the design and preparation of high-performance heterostructured materials of interest in energy-related applications.