Enhanced On‐Site Hydrogen Peroxide Electrosynthesis by a Selectively Carboxylated N‐Doped Graphene Catalyst

Abstract

AbstractPractical‐scale on‐site production of hydrogen peroxide (H2O2) via two‐electron (2e−) oxygen reduction reaction (ORR) relies on efficient, robust, and selective electrocatalysts. Among them, carbon‐based materials are cheap, abundant, durable, and their surface properties can be tuned to favor the 2e− ORR pathways, resulting in higher efficiency and facilitating possible scale‐up towards commercially appealing levels. Here, we demonstrate that the selective installment of carboxyl groups on the surface of N‐doped graphene yielding a material named graphene acid (N‐GA) promotes the catalytic 2e− ORR, achieving a H2O2 faradaic efficiency (FE) as high as 70 % in acidic media (pH=0.96) and a H2O2 productivity in long term bulk electrolysis that could reach 107.8 mmol gcatalyst−1 h−1 under optimized conditions. Extended XPS analysis and density functional theory (DFT) calculations revealed that surface carboxylic acid functional groups play a significant role in achieving the high activity of N‐GA for 2e− ORR.