Synthesis of hollow amorphous cobalt phosphide-cobalt oxide composite with interconnected pores for oxygen evolution reaction

Abstract

Abstract Interconnected porous structures and amorphous materials are widely used in the field of electrocatalysis owing to their rich catalytic active sites. Amorphous CoPx-CoOy composites with interconnected porous structures were constructed through low-temperature phosphating of cobalt oxides. Moreover, low-temperature phosphating of cobalt oxide and other metal oxides with different morphologies also produced the same porous structures, further proving the generality of this method. Interestingly, the prepared CoPx-CoOy catalyst has excellent electrocatalytic activity for oxygen evolution reactions in alkaline media. At a current density of 10 mA cm−2, an overpotential of 322 mV and a Tafel slope of 102 mV dec-1 are generated. In a 1 M KOH electrolyte, its electrochemical activity is significantly better than that of unphosphorylated Co3O4. Under catalytic conditions, the excellent performance arises from the formation of the incorporation of phosphorus, amorphous phase and porous structures. The unique structure can provide a large number of active sites, significantly shortening the electron transfer pathway. This is the foundation of our research on the development of electrocatalysts with rich active sites. The synthesis of amorphous interconnected porous structures by introducing phosphorus will allow the application of high-efficiency catalysts in electrocatalysis and other important chemical reactions.