美国俄亥俄州立大学Anne C. Co团队报道了Au上CO₂电还原过程中CO的负反应级数。相关研究成果发表在2024年8月19日出版的《美国化学会杂志》。

在传质控制条件下，使用旋转环盘电极装置测量了Au上CO₂电还原（CO₂R）对于CO分压的电位依赖性负分数反应级数。在高过电位下，由于CO在Au上的吸附增强，CO反应级数接近1，并通过动力学分析和密度泛函理论（DFT）模拟进行了验证。

该项工作表明，即使在电化学环境中的Au等弱CO结合金属上，CO位点阻断效应也不容忽视。CO位点阻断效应会极大地阻碍CO₂R对CO的活性和选择性。这一观察丰富了目前对CO₂R的机理理解，不仅在CO₂R的理论建模方面，而且在实际电流密度和高转化条件下对内在CO₂R活性的评估方面都具有重要意义。

附：英文原文

Title: Negative Reaction Order for CO during CO2 Electroreduction on Au

Author: Zhihao Cui, Andrew Jark-Wah Wong, Michael J. Janik, Anne C. Co

Issue&Volume: August 19, 2024

Abstract: The potential-dependent negative fractional reaction orders with respect to the CO partial pressures were measured for CO2 electroreduction (CO2R) on Au under mass-transfer-controlled conditions using a rotating ring-disk electrode setup. At high overpotentials, the CO reaction order approaches 1 due to enhanced CO adsorption on Au, which is supported by kinetic analysis and density functional theory (DFT) simulations. This work illustrates that the CO site-blocking effect cannot be ignored, even on a weak CO-binding metal such as Au in the electrochemical environment. The CO site-blocking effect can greatly hamper the activity and the selectivity of the CO2R to CO. This observation enriches the current mechanistic understanding of the CO2R and could have significant implications not only in the theoretical modeling of the CO2R but also in the evaluation of intrinsic CO2R activity at practical current density and high conversion conditions.

DOI: 10.1021/jacs.4c06232

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c06232