Ligand-Controlled Electroreduction of CO<sub>2</sub> to Formate over Facet-Defined Bimetallic Sulfide Nanoplates.

Liu, Yang; Jiang, Zhou; Huang, Chuanliang; Jeong, Soojin; Coughlin, Amanda L; Zhang, Shixiong; Liu, Yuanyue; Ye, Xingchen · Nano Lett · 2023

basic_science · Level V

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Abstract

CO<sub>2</sub> reduction (CO<sub>2</sub>R) catalyzed by an efficient, stable, and earth-abundant electrocatalyst offers an attractive means to store energy derived from renewable sources. Here, we describe the synthesis of facet-defined Cu<sub>2</sub>SnS<sub>3</sub> nanoplates and the ligand-controlled CO<sub>2</sub>R property. We show that thiocyanate-capped Cu<sub>2</sub>SnS<sub>3</sub> nanoplates possess excellent selectivity toward formate over a wide range of potentials and current densities, attaining a maximum formate Faradaic efficiency of 92% and partial current densities as high as 181 mA cm<sup>-2</sup> when tested using a flow cell with gas-diffusion electrode. In situ spectroscopic measurements and theoretical calculations reveal that the high formate selectivity originates from favorable adsorption of HCOO* intermediates on cationic Sn sites that are electronically modulated by thiocyanates bound to adjacent Cu sites. Our work illustrates that well-defined multimetallic sulfide nanocrystals with tailored surface chemistries could provide a new avenue for future CO<sub>2</sub>R electrocatalyst design.