Surface dynamic engineering of discontinuous cobalt dopants on copper sulfide for enhanced electrosynthesis of hydrogen peroxide

Electrochemical synthesis of hydrogen peroxide (H₂O₂) represents a sustainable, economical, and energy-efficient approach but faces challenges due to sluggish and complicated 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 (2e^--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-CuS_ED). This design optimizes the microelectronic structure at the electrocatalytic interface, enhancing the 2e^--ORR pathway over the 4-electron pathway. The optimized Co-CuS_ED achieves a high H₂O₂ production rate of 1.10 mol g_cat ^-1 h^-1. Using this catalyst in a dual cathode system for <i>in situ</i> 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.