Cation Effects on the Acidic Oxygen Reduction Reaction at Carbon Surfaces

J L Hübner; L E B Lucchetti; H N Nong; D I Sharapa; B Paul; M Kroschel; J Kang; D Teschner; S Behrens; F Studt; A Knop-Gericke; S Siahrostami; P Strasser

doi:10.1021/acsenergylett.3c02743

Cation Effects on the Acidic Oxygen Reduction Reaction at Carbon Surfaces

ACS Energy Lett. 2024 Mar 1;9(4):1331-1338. doi: 10.1021/acsenergylett.3c02743. eCollection 2024 Apr 12.

Authors

J L Hübner¹, L E B Lucchetti², H N Nong¹, D I Sharapa³, B Paul¹, M Kroschel¹, J Kang¹, D Teschner^{4

5}, S Behrens³, F Studt³, A Knop-Gericke^{4

5}, S Siahrostami⁶, P Strasser¹

Affiliations

¹ Department of Chemistry, Chemical Engineering Division, Technical University of Berlin, 10623 Berlin, Germany.
² Centro de Ciências Naturais e Humanas, Federal University of ABC, Bairro Bangu, 09210-170 Santo André, Brazil.
³ Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany.
⁴ Department of Inorganic Chemistry, Fritz-Haber-Institute of the Max-Planck-Society, 14195 Berlin, Germany.
⁵ Department of Heterogeneous Reactions, Max-Planck-Institute for Chemical Energy Conversion, 45470 Mülheim an der Ruhr, Germany.
⁶ Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada.

Abstract

Hydrogen peroxide (H₂O₂) is a widely used green oxidant. Until now, research has focused on the development of efficient catalysts for the two-electron oxygen reduction reaction (2e^- ORR). However, electrolyte effects on the 2e^- ORR have remained little understood. We report a significant effect of alkali metal cations (AMCs) on carbons in acidic environments. The presence of AMCs at a glassy carbon electrode shifts the half wave potential from -0.48 to -0.22 V_RHE. This cation-induced enhancement effect exhibits a uniquely sensitive on/off switching behavior depending on the voltammetric protocol. Voltammetric and in situ X-ray photoemission spectroscopic evidence is presented, supporting a controlling role of the potential of zero charge of the catalytic enhancement. Density functional theory calculations associate the enhancement with stabilization of the *OOH key intermediate as a result of locally induced field effects from the AMCs. Finally, we developed a refined reaction mechanism for the H₂O₂ production in the presence of AMCs.