Advanced Carbon Electrocatalysts for Selective Oxygen Reduction into Hydrogen Peroxide: Understandings of Active Sites

Abstract

Review Advanced Carbon Electrocatalysts for Selective Oxygen Reduction into Hydrogen Peroxide: Understandings of Active Sites Jiaxin Su 1,2, Bingbing Xiao 1,2, Jun Wang 1,2,* and Xiaofeng Zhu 1,2,* 1 State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, China 2 Tianfu Institute of Research and Innovation, Southwest University of Science and Technology, Chengdu 610299, China * Correspondence: junwang091@163.com (J.W.); xfzhu@swust.edu.cn (X.Z.) Received: 17 January 2024; Revised: 25 January 2024; Accepted: 19 February 2024; Published: 5 March 2024 Abstract: Electrochemical conversion of oxygen-to-hydrogen peroxide (H2O2) through oxygen reduction (ORR) is becoming a green and effective solution to replacing conventional anthraquinone industry. Advanced carbon is currently one of the most promising catalysts for H2O2 electrosynthesis by a selective two-electron ORR (2e-ORR), owing to its chemical and catalytic merits. To realize better performance of 2e-ORR over advanced carbons, extensive efforts is devoted to constructing highly efficient carbon-based active sites, which requests in-depth understanding of their underlying catalytic roles. Here, an informative and critical review of recent investigations on active sites on advanced carbons for 2e-ORR is provided. Together with our recent findings, the review first highlights the promoting progress on heteroatom-doped carbons, and their direct/indirect contributions for 2e-ORR has been emphasized. Simultaneously, defect engineering of carbon scaffold is briefly demonstrated as a practical strategy for achieving outstanding H2O2 production. Meanwhile, the review also offers analysis on striking influence of surface modification for carbon active site. Finally, challenges and perspectives of the advanced carbon catalysts for 2e-ORR are outlined. Such reviewed fundamentals of active sites in this emerging field would shed light to future impactful progress in ORR and broader research of energy and catalysis.