Shan Wanyu, Liu Rui, Zhao Huachao, He Zuoliang, Lai Yujian, Li Shasha, He Guangzhi, Liu Jingfu
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Nano. 2020 Sep 22;14(9):11363-11372. doi: 10.1021/acsnano.0c03534. Epub 2020 Aug 17.
The electrocatalytic reduction of CO (COER) to liquid fuels is important for solving fossil fuel depletion. However, insufficient insight into the reaction mechanisms renders a lack of effective regulation of liquid product selectivity. Here, surface-enhanced Raman spectroscopy (SERS) empowered by C/C isotope exchange is applied to probing the COER process on nanoporous silver (np-Ag). Direct spectroscopic evidence of the preliminary intermediates, *COOH and *OCO, indicates that CO is coordinated to the catalyst diverse adsorption modes. Further, the relative Raman intensities of the above intermediates vary notably on np-Ag modified by Cu or Pd, and the liquid product selectivity also changes accordingly. Combined with density functional theory calculations, this study demonstrates that the CO adsorption configuration is a critical factor governing the reaction selectivity. Meanwhile, *COOH and *OCO are key targets in the initial stage regulating liquid product selectivity, which could facilitate future selective catalyst design.
将一氧化碳电催化还原（COER）为液体燃料对于解决化石燃料枯竭问题具有重要意义。然而，对反应机理的认识不足导致缺乏对液体产物选择性的有效调控。在此，采用由碳/碳同位素交换赋能的表面增强拉曼光谱（SERS）来探测纳米多孔银（np-Ag）上的COER过程。初级中间体COOH和OCO的直接光谱证据表明，CO以多种吸附模式与催化剂配位。此外，上述中间体的相对拉曼强度在经铜或钯修饰的np-Ag上有显著变化，液体产物选择性也相应改变。结合密度泛函理论计算，本研究表明CO吸附构型是决定反应选择性的关键因素。同时，COOH和OCO是调控液体产物选择性初始阶段的关键目标，这有助于未来选择性催化剂的设计。
