Amorphous CoFePOx hollow nanocubes decorated with g-C3N4 quantum dots to achieve efficient electrocatalytic performance in the oxygen evolution reaction

Abstract

Simultaneously enriching active sites and enhancing intrinsic activity in a simple way is of great importance for the design of highly active electrocatalysts for the oxygen evolution reaction (OER), but it still faces challenges. Herein, g-C₃N₄ quantum dot decorated amorphous hollow CoFe bimetallic phosphate nanocubes (a-CoFePO_x@CNQD) are prepared as an efficient OER electrocatalyst by a simple in situ etching–phosphating process. Research shows that their unique hollow architecture and amorphous structure can help provide generous exposed active sites for OER, and the incorporation of g-C₃N₄ quantum dots can effectively adjust the electronic structure to improve the intrinsic activity. Therefore, a-CoFePO_x@CNQD exhibits excellent OER performance with a low overpotential (239 mV) at 10 mA cm⁻² and a small Tafel slope (58.4 mV dec⁻¹), surpassing the commercial RuO₂. Furthermore, a-CoFePO_x@CNQD as an electrode catalyst for a water electrolyzer and zinc–air battery also shows higher performance and stability than RuO₂ + Pt/C catalysts. This study provides a feasible strategy for preparing efficient and stable amorphous hollow heterostructure OER electrocatalysts.