CO2/carbonate-mediated electrochemical water oxidation to hydrogen peroxide

Lei Fan; Xiaowan Bai; Chuan Xia; Xiao Zhang; Xunhua Zhao; Yang Xia; Zhen-Yu Wu; Yingying Lu; Yuanyue Liu; Haotian Wang

doi:10.1038/s41467-022-30251-5

CO₂/carbonate-mediated electrochemical water oxidation to hydrogen peroxide

Nat Commun. 2022 May 13;13(1):2668. doi: 10.1038/s41467-022-30251-5.

Authors

Lei Fan^#^{1

2}, Xiaowan Bai^#³, Chuan Xia^#^{1

4}, Xiao Zhang¹, Xunhua Zhao³, Yang Xia¹, Zhen-Yu Wu¹, Yingying Lu⁵, Yuanyue Liu⁶, Haotian Wang^{7

8

9}

Affiliations

¹ Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
² State Key Laboratory of Chemical Engineering, Institute of Pharmaceutical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China.
³ Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
⁴ Smalley-Curl Institute, Rice University, Houston, TX, 77005, USA.
⁵ State Key Laboratory of Chemical Engineering, Institute of Pharmaceutical Engineering, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, 310027, China. yingyinglu@zju.edu.cn.
⁶ Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. Yuanyue.liu@austin.utexas.edu.
⁷ Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.
⁸ Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.
⁹ Department of Chemistry, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.

^# Contributed equally.

Abstract

Electrochemical water oxidation reaction (WOR) to hydrogen peroxide (H₂O₂) via a 2e^- pathway provides a sustainable H₂O₂ synthetic route, but is challenged by the traditional 4e^- counterpart of oxygen evolution. Here we report a CO₂/carbonate mediation approach to steering the WOR pathway from 4e^- to 2e^-. Using fluorine-doped tin oxide electrode in carbonate solutions, we achieved high H₂O₂ selectivity of up to 87%, and delivered unprecedented H₂O₂ partial currents of up to 1.3 A cm^-2, which represents orders of magnitude improvement compared to literature. Molecular dynamics simulations, coupled with electron paramagnetic resonance and isotope labeling experiments, suggested that carbonate mediates the WOR pathway to H₂O₂ through the formation of carbonate radical and percarbonate intermediates. The high selectivity, industrial-relevant activity, and good durability open up practical opportunities for delocalized H₂O₂ production.