Strategy for Enhancing Catalytic Active Site: Introduction of 1D material InSeI for Electrochemical CO₂ Reduction to Formate

The presence of oxygen vacancies (V_o) in electrocatalysts plays a significant role in improving the selectivity and activity of CO₂ reduction reaction (CO₂RR). In this study, 1D material with large surface area is utilized to enable uniform V_o formation on the catalyst. 1D structured indium selenoiodide (InSeI) is synthesized and used as an electrocatalyst for the conversion of CO₂ to formate. The electrochemical treatment of InSeI leads to the leaching of Se and I from the catalyst surface and the formation of V_o. The resulting V_o promotes the activity of the CO₂RR, which increases the local pH of the catalyst surface and chemically maintains the oxidized metal sites on the catalyst. Owing to these characteristics, activated In wire exhibited remarkable CO₂RR activity, thereby surpassing 93% FE_formate at 500 mA cm^-2, with a maximum of 97.3% FE_formate at 100 mA cm^-2. Moreover, the catalytic activity remained consistent for over 50 h at 100 mA cm^-2 (FE_formate >88%). Thus, the findings imply that using 1D materials can facilitate the formation of oxygen vacancies on the catalyst surface and improve the selectivity and durability of CO₂RR. This indicates the potential for further research on 1D materials as electrocatalysts.