Sequentially Regulating Potential-Determining Step for Lowering CO 2 Electroreduction Overpotential over Te-Doped Bi Nanotips

• Published in: Angewandte Chemie International Edition 2024-09, Vol.63 (36), p.e202407772
• Main Authors: Li, Youzeng, Li, Jinhan, Ai, Wei, Chen, Jialei, Lu, Tiantian, Liao, Xuelong, Wang, Wei, Huang, Rong, Chen, Zhuo, Wu, Jinxiong, Cheng, Fangyi, Wang, Huan
• Format: Article
• Language: English
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202407772

Electrocatalytic conversion of CO into formate is recognized an economically-viable route to upgrade CO , but requires high overpotential to realize the high selectivity owing to high energy barrier for driving the involved proton-coupled electron transfer (PCET) processes and serious ignorance of the second PCET. Herein, we surmount the challenge through sequential regulation of the potential-determining step (PDS) over Te-doped Bi (TeBi) nanotips. Computational studies unravel the incorporation of Te heteroatoms alters the PDS from the first PCET to the second one by substantially lowering the formation barrier for *OCHO intermediate, and the high-curvature nanotips induce enhanced electric field that can steer the formation of asymmetric *HCOOH. In this scenario, the thermodynamic barrier for *OCHO and *HCOOH can be sequentially decreased, thus enabling a high formate selectivity at low overpotential. Experimentally, distinct TeBi nanostructures are obtained via controlling Te content in the precursor and TeBi nanotips achieve >90 % of Faradaic efficiency for formate production over a comparatively positive potential window (-0.57 V to -1.08 V). The strong Bi-Te covalent bonds also afford a robust stability. In an optimized membrane electrode assembly device, the formate production rate at 3.2 V reaches 10.1 mmol h  cm , demonstrating great potential for practical application.