Construction of 2D heterostructure Fe2P–CoP2/MoOx nanosheets for efficient oxygen evolution reaction

Abstract

The oxygen evolution reaction (OER) plays a pivotal role in diverse electrochemical conversion applications, such as water splitting and metal–air batteries. Nevertheless, the formation of several active sites in catalysts made of non-noble metals continues to encounter notable obstacles. To tackle this challenge, a 2D heterostructure catalyst composed of Fe₂P–CoP₂/MoO_x nanosheets was designed. The cobalt molybdate (CoMoO₄) nanosheets and their supported FeOOH nanoflakes were in situ transformed into 2D heterostructure Fe₂P–CoP₂/MoO_x nanosheets via a simple hydrothermal and phosphorization process. Note that the 2D MoO_x nanosheets significantly enhance the electrochemically active surface area (ECSA), and there is a synergistic effect between cobalt phosphide (CoP₂) and iron phosphide (Fe₂P) nanoparticles, improving the OER reaction activity. When the electrocatalyst was employed for the OER, the Fe₂P–CoP₂/MoO_x nanosheets exhibit remarkable OER efficiency, reducing overpotentials to as low as 235 mV at a current density of 50 mA cm⁻², accompanied by a Tafel slope of 33.32 mV dec⁻¹, along with exceptional enduring stability. The synthesis of the 2D heterostructure Fe₂P–CoP₂–MoO_x nanosheets and their remarkable OER performance represent substantial advancements in developing electrocatalysts that are productive and stable in sustainable energy conversion and storage applications.