Unlocking the Potential of Bi2S3‐Derived Bi Nanoplates: Enhanced Catalytic Activity and Selectivity in Electrochemical and Photoelectrochemical CO2 Reduction to Formate

• Published in: Advanced science 2024-07, Vol.11 (28), p.e2400874-n/a
• Main Authors: Ma, Ahyeon, Lee, Yongsoon, Seo, Dongho, Kim, Jiyoon, Park, Soohyeok, Son, Jihoon, Kwon, Woosuck, Nam, Dae‐Hyun, Lee, Hyosung, Kim, Yong‐Il, Um, Han‐Don, Shin, Hyeyoung, Nam, Ki Min
• Format: Article
• Language: English
• Subjects: Bi nanoplates; Carbon; CO2 reduction; formate production; Fourier transforms; Morphology; Phase transitions; photoelectrochemical reaction; Scanning electron microscopy; silicon nanowires; Spectrum analysis
• ISSN: 2198-3844; 2198-3844
• DOI: 10.1002/advs.202400874

Various electrocatalysts are extensively examined for their ability to selectively produce desired products by electrochemical CO2 reduction reaction (CO2RR). However, an efficient CO2RR electrocatalyst doesn't ensure an effective co‐catalyst on the semiconductor surface for photoelectrochemical CO2RR. Herein, Bi2S3 nanorods are synthesized and electrochemically reduced to Bi nanoplates that adhere to the substrates for application in the electrochemical and photoelectrochemical CO2RR. Compared with commercial‐Bi, the Bi2S3‐derived Bi (S‐Bi) nanoplates on carbon paper exhibit superior electrocatalytic activity and selectivity for formate (HCOO−) in the electrochemical CO2RR, achieving a Faradaic efficiency exceeding 93%, with minimal H2 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 CO2RR. 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 CO2RR using the S‐Bi catalyst correlates with that seen in the photoelectrochemical CO2RR 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 CO2‐to‐HCOO− conversion. The study demonstrates the transformation of Bi2S3 nanorods into Bi nanoplates (S‐Bi), yielding catalysts highly effective in CO2‐to‐HCOO− conversion in electrochemical and photoelectrochemical systems. Defect states in the catalysts significantly aid HCOO− production. S‐Bi/SiNWs photocathodes show remarkable activity and selectivity, suppressing H2 generation via pulsed electrolysis. These findings highlight the effectiveness of S‐Bi as a catalyst for CO2 reduction reactions.