Origin of the overpotentials for HCOO- and CO formation in the electroreduction of CO2 on Cu(211): the reductive desorption processes decide
Origin of the overpotentials for HCOO- and CO formation in the electroreduction of CO2 on Cu(211): the reductive desorption processes decide
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Cu(211) 上 CO2 电还原过程中 HCOO- 和 CO 形成过电势的起源：还原解吸过程决定
DOI：
10.1039/c7cp08440d
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发表时间：
2018
影响因子：
3.3
通讯作者：
Liu Chungen
中科院分区：
文献类型：
--
作者：
Liu Ling;Liu Chungen
CO2在铜表面的电还原为生产碳氢化合物和其他多碳产品提供了潜力。然而，需要全面了解电位相关的机制，以提高产品的选择性，以及降低过电位。在此，我们系统地表征了Cu（211）表面上CO和HCOO−的完整反应途径的潜在影响。反应自由能和活化能作为电势的函数计算。研究发现，CO2的化学吸附状态被基底有效地稳定，预计在低于-0.27 V vs. SHE的电位下占主导地位，比先前报道的Cu（100）要早得多。考虑到其他表面过程的活化势垒足够小，可以在室温下克服，OH-和HCOO-的大还原脱附自由能被认为是高过电位的起源。
Electroreduction of CO2 on Cu surface provides the potential in producing hydrocarbons and other multi-carbon products. However, a comprehensive understanding of the potential-related mechanism is required to improve the product selectivity as well as to reduce the overpotentials. Herein, we systematically characterize the potential effect on the complete reaction pathways to CO and HCOO− on the Cu(211) surface. Reaction free energy and activation barrier are computed as functions of electric potential. It is found that chemical adsorption state of CO2 is effectively stabilized by the substrate, which is expected to be dominant at potentials below −0.27 V vs. SHE, much earlier than that previously reported on Cu(100). Considering that the activation barriers of the other surface processes are small enough to be overcome at room temperature, the large reductive desorption free energies of OH− and HCOO− are suggested as the origin of high overpotentials.