Double layer charging driven carbon dioxide adsorption limits the rate of electrochemical carbon dioxide reduction on Gold
Double layer charging driven carbon dioxide adsorption limits the rate of electrochemical carbon dioxide reduction on Gold
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DOI：
10.1038/s41467-019-13777-z
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发表时间：
2020-01-07
影响因子：
16.6
通讯作者：
Chan, Karen
中科院分区：
文献类型：
--
作者：
Ringe, Stefan;Morales-Guio, Carlos G.;Chan, Karen
电化学减少二氧化碳是可持续生产有价值的燃料和化学品的潜在途径。在这里，我们在中性到酸性pH值下对金进行CO2还原实验，以阐明围绕限速步骤的长期争议。我们发现，在标准氢电极尺度上，CO产率随pH不变，并得出结论，CO产率受CO2吸附步骤的限制。我们提出了一种新的多尺度建模方案，将从头算反应动力学与质量传递模拟相结合，明确考虑了带电双电层。该模型再现了实验CO极化曲线，并揭示了低过电位下的*COOH到*CO、中过电位下的CO2吸附和高过电位下的CO2质量输运的限速步骤。最后，我们证明了Tafel斜率是由CO2偶极子与界面场之间的静电相互作用引起的。这项工作强调了表面充电对电化学动力学和质量传输的重要性。
Electrochemical CO2 reduction is a potential route to the sustainable production of valuable fuels and chemicals. Here, we perform CO2 reduction experiments on Gold at neutral to acidic pH values to elucidate the long-standing controversy surrounding the rate-limiting step. We find the CO production rate to be invariant with pH on a Standard Hydrogen Electrode scale and conclude that it is limited by the CO2 adsorption step. We present a new multi-scale modeling scheme that integrates ab initio reaction kinetics with mass transport simulations, explicitly considering the charged electric double layer. The model reproduces the experimental CO polarization curve and reveals the rate-limiting step to be *COOH to *CO at low overpotentials, CO2 adsorption at intermediate ones, and CO2 mass transport at high overpotentials. Finally, we show the Tafel slope to arise from the electrostatic interaction between the dipole of *CO2 and the interfacial field. This work highlights the importance of surface charging for electrochemical kinetics and mass transport.