Affiliation:
1. Institute of Nanochemistry and Nanobiology School of Environmental and Chemical Engineering Shanghai University 99 Shangda Road, BaoShan District Shanghai 200444 P. R. China
2. School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore
Abstract
AbstractHydrogen peroxide (H2O2) has emerged as a kind of multi‐functional green oxidants with extensive industrial utility. Oxidized carbon materials exhibit promises as electrocatalysts in the two‐electron (2e−) oxygen reduction reaction (ORR) for H2O2 production. However, the precise identification and fabrication of active sites that selectively yield H2O2 present a serious challenge. Herein, a structural engineering strategy is employed to synthesize oxygen‐doped carbon quantum dots (o‐CQD) for the 2e− ORR. The surface electronic structure of the o‐CQDs is systematically modulated by varying isomerization precursors, thereby demonstrating excellent electrocatalyst performance. Notably, o‐CQD‐3 emerges as the most promising candidate, showcasing a remarkable H2O2 selectivity of 96.2% (n = 2.07) at 0.68 V versus RHE, coupled with a low Tafel diagram of 66.95 mV dec−1. In the flow cell configuration, o‐CQD‐3 achieves a H2O2 productivity of 338.7 mmol gcatalyst−1 h−1, maintaining consistent production stability over an impressive 120‐hour duration. Utilizing in situ technology and density functional theory calculations, it is unveil that edge sites of o‐CQD‐3 are facilely functionalized by C‐O‐C groups under alkaline ORR conditions. This isomerization engineering approach advances the forefront of sustainable catalysis and provides a profound insight into the carbon‐based catalyst design for environmental‐friendly chemical synthesis processes.