Toward More Efficient Carbon-Based Electrocatalysts for Hydrogen Peroxide Synthesis: Roles of Cobalt and Carbon Defects in Two-Electron ORR Catalysis

Yuanjie Zheng; Peng Wang; Wei-Hsiang Huang; Chi-Liang Chen; Yanyan Jia; Sheng Dai; Tan Li; Yun Zhao; Yongcai Qiu; Geoffrey I N Waterhouse; Guangxu Chen

doi:10.1021/acs.nanolett.2c04901

Toward More Efficient Carbon-Based Electrocatalysts for Hydrogen Peroxide Synthesis: Roles of Cobalt and Carbon Defects in Two-Electron ORR Catalysis

Nano Lett. 2023 Feb 8;23(3):1100-1108. doi: 10.1021/acs.nanolett.2c04901. Epub 2023 Jan 24.

Authors

Yuanjie Zheng¹, Peng Wang¹, Wei-Hsiang Huang^{2

3}, Chi-Liang Chen^{2

3}, Yanyan Jia⁴, Sheng Dai⁴, Tan Li¹, Yun Zhao¹, Yongcai Qiu¹, Geoffrey I N Waterhouse⁵, Guangxu Chen¹

Affiliations

¹ School of Environment and Energy, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control, South China University of Technology, Guangzhou 51006, China.
² National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
³ Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
⁴ Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Centre, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China.
⁵ School of Chemical Sciences, The University of Auckland, Auckland 1142, New Zealand.

PMID: 36692959
DOI: 10.1021/acs.nanolett.2c04901

Abstract

Electrochemical production of H₂O₂ is a cost-effective and environmentally friendly alternative to the anthraquinone-based processes. Metal-doped carbon-based catalysts are commonly used for 2-electron oxygen reduction reaction (2e^-ORR) due to their high selectivity. However, the exact roles of metals and carbon defects on ORR catalysts for H₂O₂ production remain unclear. Herein, by varying the Co loading in the pyrolysis precursor, a Co-N/O-C catalyst with Faradaic efficiency greater than 90% in alkaline electrolyte was obtained. Detailed studies revealed that the active sites in the Co-N/O-C catalysts for 2e^-ORR were carbon atoms in C-O-C groups at defect sites. The direct contribution of cobalt single atom sites and metallic Co for the 2e^-ORR performance was negligible. However, Co plays an important role in the pyrolytic synthesis of a catalyst by catalyzing carbon graphitization, tuning the formation of defects and oxygen functional groups, and controlling O and N concentrations, thereby indirectly enhancing 2e^-ORR performance.

Keywords: 2-electron oxygen reduction reaction; H2O2 production; carbon-based catalyst; cobalt doping.