Selective Substitution of Cobalt Dopant Sites by Edge Defects on Copper Sulfide Catalyst for Efficient Hydrogen Peroxide Electrosynthesis and Organic Pollutant Degradation

Electrochemical synthesis of hydrogen peroxide (H2O2) represents a sustainable, economical, and energy-efficient approach but faces challenges due to sluggish and complicate dynamics at the solid/liquid/gas interface. This study leverages theoretical insights from CuS surface microenvironments, demonstrating that cobalt doping and edge defects on CuS can thermodynamically favor the 2-electron oxygen reduction reaction (ORR) pathway for H2O2 production. To validate theoretical predictions, we synthesized a catalyst featuring interleaved hexagonal lamellar copper sulfide with discontinuous cobalt dopants at the edges and complementary defects (Co-CuSED). This design optimizes the microelectronic structure at the electrocatalytic interface, enhancing the 2-electron oxygen reduction reaction (ORR) pathway over the 4-electron pathway. The optimized Co-CuSED achieves a high H2O2 production rate of 1.04 mol g−1 h−1. Using this catalyst in a dual cathode system for in-situ H2O2 generation results in rapid degradation of organic dyes, reaching 92% efficiency within 20 minutes. This work presents an environmentally friendly, cost-effective, and efficient strategy for H2O2 electrosynthesis, with strong potential for wastewater remediation.