Electrochemical oxygen reduction to hydrogen peroxide at practical rates in strong acidic media

Xiao Zhang; Xunhua Zhao; Peng Zhu; Zachary Adler; Zhen-Yu Wu; Yuanyue Liu; Haotian Wang

doi:10.1038/s41467-022-30337-0

Electrochemical oxygen reduction to hydrogen peroxide at practical rates in strong acidic media

Nat Commun. 2022 May 24;13(1):2880. doi: 10.1038/s41467-022-30337-0.

Authors

Xiao Zhang^#¹, Xunhua Zhao^#², Peng Zhu³, Zachary Adler³, Zhen-Yu Wu³, Yuanyue Liu⁴, Haotian Wang^{5

6

7}

Affiliations

¹ Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA. xiao1.zhang@polyu.edu.hk.
² Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
³ Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA.
⁴ Texas Materials Institute and Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA. yuanyue.liu@austin.utexas.edu.
⁵ Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.
⁶ Department of Chemistry, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.
⁷ Department of Materials Science and NanoEngineering, Rice University, Houston, TX, 77005, USA. htwang@rice.edu.

^# Contributed equally.

Abstract

Electrochemical oxygen reduction to hydrogen peroxide (H₂O₂) in acidic media, especially in proton exchange membrane (PEM) electrode assembly reactors, suffers from low selectivity and the lack of low-cost catalysts. Here we present a cation-regulated interfacial engineering approach to promote the H₂O₂ selectivity (over 80%) under industrial-relevant generation rates (over 400 mA cm^-2) in strong acidic media using just carbon black catalyst and a small number of alkali metal cations, representing a 25-fold improvement compared to that without cation additives. Our density functional theory simulation suggests a "shielding effect" of alkali metal cations which squeeze away the catalyst/electrolyte interfacial protons and thus prevent further reduction of generated H₂O₂ to water. A double-PEM solid electrolyte reactor was further developed to realize a continuous, selective (∼90%) and stable (over 500 hours) generation of H₂O₂ via implementing this cation effect for practical applications.

Abstract

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