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Interfacial O2 Accumulation Affects Microenvironment in Carbon-Based Electrocatalysts for H2O2 Production
ACS Energy Letters ( IF 19.3 ) Pub Date : 2022-11-14 , DOI: 10.1021/acsenergylett.2c02021
Chaowei Yang 1 , Fei Sun 1 , Zhibin Qu 1 , Xuhan Li 1 , Wei Zhou 1 , Jihui Gao 1
Affiliation  

Electroreduction of oxygen (O2) over carbonaceous catalysts provides an attractive approach for H2O2 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 H2O2 production activity and selectivity, which are still unclear. Here, we find that simply altering the O2 diffusion kinetics in a carbonaceous gas diffusion electrode could achieve approximately 100% Faradaic efficiency for H2O2 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 (*O2, *OOH) and inhibits the protonation process within the reaction microenvironment, thus enabling a high H2O2 production selectivity.

中文翻译:

界面 O2 积累影响用于 H2O2 生产的碳基电催化剂中的微环境

氧气 (O 2 ) 在含碳催化剂上的电还原为 H 2 O 2生产提供了一种有吸引力的方法。除了调节碳催化剂的本征催化活性外,反应物在碳电极界面微环境中的传质和扩散对H 2 O 2的生成活性和选择性也有重要影响,目前尚不清楚。在这里,我们发现即使在 30 mA cm 的高电流密度下,简单地改变含碳气体扩散电极中的 O 2扩散动力学也可以实现大约 100% 的 H 2 O 2生产法拉第效率–2。结合电化学动力学分析、扩散特性模拟和原位表征,我们揭示了氧-积累界面不仅可以提供更多的三相接触点以提高活性位点的利用效率,还可以增加局部 pH 值,从而稳定中间体 (*O 2 , *OOH) 并抑制反应微环境中的质子化过程,从而实现高 H 2 O 2生产选择性。
更新日期:2022-11-14
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