Electrochemical Production of Formic Acid from CO2 with Cetyltrimethylammonium Bromide-Assisted Copper-Based Catalysts

The electrochemical reduction of CO2 (ERC) to valuable chemicals has attracted extensive attention. However, the relatively low selectivity and efficiency of the reaction remain challenges. In this study, Cu electrodes derived from Cu2O with predominant (111) facets are synthesized by cetyltrimethylammonium bromide-assisted preparation. The optimized electrode shows a high faradaic efficiency of 90 % for HCOOH obtained by ERC at -2.0 V (vs.SCE), which surpasses most reported Cu electrodes. Based on a comprehensive analysis of the relationship between the catalytic activity and the thickness of the Cu2O layer, the catalytic activity of the unit active site on the Cu2O-derived Cu electrodes is found to be higher than that on the blank Cu electrode. DFT calculations indicate that OCHO* would be produced preferentially over *COOH in the presence of cetyltrimethylammonium bromide (CTAB). This deduction is verified by testing of the effects of CTAB and KBr addition on HCOO- selectivity.

Automated summary

This study focuses on the electrochemical reduction of CO2 to valuable chemicals using Cu electrodes derived from Cu2O with predominant (111) facets. The optimized electrode shows high faradaic efficiency for HCOOH production, surpassing most reported Cu electrodes. The catalytic activity of unit active sites on Cu2O-derived Cu electrodes is found to be higher than that on blank Cu electrodes, with OCHO* production being favored in the presence of cetyltrimethylammonium bromide.