Amphipathic Surfactant on Reconstructed Bismuth Enables Industrial-Level Electroreduction of CO<sub>2</sub> to Formate.

Chen, Yiqun; Zhang, Yan; Li, Zhen; Liu, Mengjie; Wu, Qiang; Lo, Tsz Woon Benedict; Hu, Zheng; Lee, Lawrence Yoon Suk · ACS Nano · 2024

basic_science · Level V

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Abstract

Developing efficient electrocatalysts for selective formate production via the electrochemical CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) is challenged by high overpotential, a narrow potential window of high Faradaic efficiency (FE<sub>formate</sub>), and limited current density (<i>J</i><sub>formate</sub>). Herein, we report a hierarchical BiOBr (CT/h-BiOBr) with surface-anchored cetyltrimethylammonium bromide (CTAB) for formate-selective large-scale CO<sub>2</sub>RR electrocatalysis. CT/h-BiOBr achieves over 90% FE<sub>formate</sub> across a wide potential range (-0.5 to -1.1 V) and an industrial-level <i>J</i><sub>formate</sub> surpassing 100 mA·cm<sup>-2</sup> at -0.7 V. <i>In situ</i> investigations uncover the reconstructed Bi(110) surface as the active phase, with CTAB playing a dual role: its hydrophobic alkyl chains create a CO<sub>2</sub>-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<sub>2</sub>RR.