Unlocking the Potential of Bi<sub>2</sub>S<sub>3</sub>‐Derived Bi Nanoplates: Enhanced Catalytic Activity and Selectivity in Electrochemical and Photoelectrochemical CO<sub>2</sub> Reduction to Formate
Ahyeon Ma, Yong‐Soon Lee, Dongho Seo, Ji-Yoon Kim, Soohyeok Park, Jihoon Son, Woosuck Kwon, Dae‐Hyun Nam, Hyosung Lee, Yong‐Il Kim, Han‐Don Um, Hyeyoung Shin, Ki Min Nam
Abstract
Abstract Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO 2 reduction reaction (CO 2 RR). However, an efficient CO 2 RR electrocatalyst doesn't ensure an effective co‐catalyst on the semiconductor surface for photoelectrochemical CO 2 RR. Herein, Bi 2 S 3 nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CO 2 RR. Compared with commercial‐Bi, the Bi 2 S 3 ‐derived Bi (S‐Bi) nanoplates on carbon paper exhibit superior electrocatalytic activity and selectivity for formate (HCOO − ) in the electrochemical CO 2 RR, achieving a Faradaic efficiency exceeding 93%, with minimal H 2 production over a wide potential range. This highly selective S‐Bi catalyst is being employed on the Si photocathode to investigate the behavior of electrocatalysts during photoelectrochemical CO 2 RR. The strong adhesion of the S‐Bi nanoplates to the Si nanowire substrate and their unique catalytic properties afford exceptional activity and selectivity for HCOO − under simulated solar irradiation. The selectivity observed in electrochemical CO 2 RR using the S‐Bi catalyst correlates with that seen in the photoelectrochemical CO 2 RR system. Combined pulsed potential methods and theoretical analyses reveal stabilization of the OCHO* intermediate on the S‐Bi catalyst under specific conditions, which is critical for developing efficient catalysts for CO 2 ‐to‐HCOO − conversion.