二氧化碳
还原(数学)
扩散
气体扩散
电极
二氧化碳电化学还原
气体扩散电极
材料科学
化学
化学工程
一氧化碳
电化学
热力学
有机化学
物理化学
工程类
物理
催化作用
数学
几何学
作者
Stefan Dieckhöfer,Denis Öhl,João R. C. Junqueira,Thomas Quast,Thomas Turek,Wolfgang Schuhmann
标识
DOI:10.1002/chem.202100387
摘要
Abstract Discerning the influence of electrochemical reactions on the electrode microenvironment is an unavoidable topic for electrochemical reactions that involve the production of OH − and the consumption of water. That is particularly true for the carbon dioxide reduction reaction (CO 2 RR), which together with the competing hydrogen evolution reaction (HER) exert changes in the local OH − and H 2 O activity that in turn can possibly affect activity, stability, and selectivity of the CO 2 RR. We determine the local OH − and H 2 O activity in close proximity to a CO 2 ‐converting Ag‐based gas diffusion electrode (GDE) with product analysis using gas chromatography. A Pt nanosensor is positioned in the vicinity of the working GDE using shear‐force‐based scanning electrochemical microscopy (SECM) approach curves, which allows monitoring changes invoked by reactions proceeding within an otherwise inaccessible porous GDE by potentiodynamic measurements at the Pt‐tip nanosensor. We show that high turnover HER/CO 2 RR at a GDE lead to modulations of the alkalinity of the local electrolyte, that resemble a 16 m KOH solution, variations that are in turn linked to the reaction selectivity.
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