Amphipathic Surfactant on Reconstructed Bismuth Enables Industrial-Level Electroreduction of CO₂ to Formate

Abstract

Developing efficient electrocatalysts for selective formate production via the electrochemical CO 2 reduction reaction (CO 2 RR) is challenged by high overpotential, a narrow potential window of high Faradaic efficiency (FE formate ), and limited current density (J formate ). Herein, we report a hierarchical BiOBr (CT/h-BiOBr) with surface-anchored cetyltrimethylammonium bromide (CTAB) for formate-selective large-scale CO 2 RR electrocatalysis. CT/h-BiOBr achieves over 90% FE formate across a wide potential range (−0.5 to −1.1 V) and an industriallevel J formate surpassing 100 mA•cm −2 at −0.7 V. In situ investigations uncover the reconstructed Bi(110) surface as the active phase, with CTAB playing a dual role: its hydrophobic alkyl chains create a CO 2 -enriching microenvironment, while its polar head groups fine-tune the electronic structure, fostering a highly active phase. This work provides valuable insights into the role of surfactants in electrocatalysis and guides the design of electrocatalysts for the large-scale CO 2 RR.