Carbon-Encapsulated Cobalt Phosphide Catalyst for Efficient Electrochemical Synthesis of Hydrogen Peroxide

Metal phosphides with high electronic conductivity are recognized as promising electrocatalyst for oxygen reduction reaction (ORR). Herein, we report a family of cobalt phosphides (CoP, CoP2, and CoP/CoP2) encapsulated in thin carbon layer as twoelectron (2e-) ORR electrocatalysts for H2O2 production. Benefiting from the regulation of cobalt phosphide, CoP/CoP2@NPC exhibited the highest H2O2 yield among the three types of cobalt phosphides studied, with a high H2O2 selectivity (90%) over a potential ranging from 0.2 to 0.7 V vs the reversible hydrogen electrode. Continuous generation of H2O2 is achieved at an outstanding rate of 1.93 mol g- h- cat. 1 1 with a Faraday efficiency of 83%.