pH 值对铜阶上 CO 电化学还原为 C 产物的影响。
pH effects on the electrochemical reduction of CO towards C products on stepped copper.
机构信息
SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, California, 94305, USA.
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California, 94025, USA.
出版信息
Nat Commun. 2019 Jan 3;10(1):32. doi: 10.1038/s41467-018-07970-9.
We present a microkinetic model for CO reduction (COR) on Cu(211) towards C products, based on energetics estimated from an explicit solvent model. We show that the differences in both Tafel slopes and pH dependence for C vs C activity arise from differences in their multi-step mechanisms. We find the depletion in C products observed at high overpotential and high pH to arise from the 2 order dependence of C-C coupling on CO coverage, which decreases due to competition from the C pathway. We further demonstrate that CO reduction at a fixed pH yield similar activities, due to the facile kinetics for CO reduction to CO on Cu, which suggests C products to be favored for COR under alkaline conditions. The mechanistic insights of this work elucidate how reaction conditions can lead to significant enhancements in selectivity and activity towards higher value C products.
我们提出了一个基于显式溶剂模型估算能垒的 CO 还原（COR）在 Cu(211)表面生成 C 产物的微观动力学模型。我们发现 C 和 C*活性的塔菲尔斜率和 pH 依赖性的差异源于它们多步反应机制的不同。我们发现高过电势和高 pH 条件下观察到 C 产物的耗尽是由于 C-C 偶联对 CO 覆盖率的 2 级依赖，这是由于 C 反应途径的竞争导致的。我们进一步证明，在固定 pH 条件下 CO 还原具有相似的活性，这是因为 CO 在 Cu 表面还原为 CO 的动力学较为容易，这表明在碱性条件下 COR 有利于生成 C 产物。这项工作的机理见解阐明了反应条件如何导致对更高价值 C 产物的选择性和活性的显著提高。
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