Surface Ligand Promotion of Carbon Dioxide Reduction through Stabilizing Chemisorbed Reactive Intermediates

• DOI: 10.1021/acs.jpclett.8b00959
• Publication Date: 2018-05-22T15:04:34Z
• Authors: Zhijiang Wang; Lina Wu; Kun Sun; Ting Chen; Zhaohua Jiang; Tao Cheng; William A. Goddard
• Keywords: 13. Climate action; 540; 01 natural sciences; 0104 chemical sciences

We have explored functionalizing metal catalysts with surface ligands as an approach to facilitate electrochemical carbon dioxide reduction reaction (CO2RR). To provide a molecular level understanding of the mechanism by which this enhancement occurs, we combine in situ spectroscopy analysis with an interpretation based on quantum mechanics (QM) calculations. We find that a surface ligand can play a critical role in stabilizing the chemisorbed CO2, which facilitates CO2 activation and leads to a 0.3 V decrease in the overpotential for carbon monoxide (CO) formation. Moreover, the presence of the surface ligand leads to nearly exclusive CO production. At -0.6 V (versus reversible hydrogen electrode, RHE), CO is the only significant product with a faradic efficiency of 93% and a current density of 1.9 mA cm-2. This improvement corresponds to 53-fold enhancement in turnover frequency compared with the Ag nanoparticles (NPs) without surface ligands.