Interfacial O 2 Accumulation Affects Microenvironment in Carbon-Based Electrocatalysts for H 2 O 2 Production

作者：Chaowei Yang, Fei Sun, Zhibin Qu, Xuhan Li, Wei Zhou, Jihui Gao · 发表于：ACS Energy Letters · 年份：2022 · DOI：10.1021/acsenergylett.2c02021 · 被引用次数：84 · 研究领域：Electrocatalysts for Energy Conversion、Advanced battery technologies research、CO2 Reduction Techniques and Catalysts

Electroreduction of oxygen (O 2 ) over carbonaceous catalysts provides an attractive approach for H 2 O 2 production. In addition to the regulation of the intrinsic catalytic activity of carbon catalysts, the mass transfer and diffusion of reactant species in the interface microenvironment of the carbon electrode also have important impacts on H 2 O 2 production activity and selectivity, which are still unclear. Here, we find that simply altering the O 2 diffusion kinetics in a carbonaceous gas diffusion electrode could achieve approximately 100% Faradaic efficiency for H 2 O 2 production even at a high current density of 30 mA cm –2 . Combining electrochemical kinetic analysis, diffusion characteristic simulation, and in situ characterization, we reveal that the oxygen-accumulation interface could not only provide more three-phase contact points to improve the utilization efficiency of active sites but also increase the local pH, which stabilizes the intermediates (*O 2 –, *OOH) and inhibits the protonation process within the reaction microenvironment, thus enabling a high H 2 O 2 production selectivity.