A mini review on carbon-based metal-free electrocatalysts for oxygen reduction reaction

Abstract

Exploration of low-cost and high-performance oxygen reduction reaction (ORR) electrocatalysts to replace Pt-based catalysts is now undergoing fast and dynamic development. Metal-free carbon-based ORR electrocatalysts have interesting catalytic activities, high stabilities, and good CO and methanol tolerances, and their constituents are abundantly available. They are therefore potential alternatives to Pt-based catalysts. This paper briefly reviews the main progress in this emerging field, in combination with studies performed by our group. Special attention is paid to electron-rich N or electron-deficient B mono-/co-doped carbon nanostructures, and the correlation between the ORR activity and the electronic structure of the sp 2 carbon material. The bright perspectives are speculated for this new kind of promising metal-free ORR electrocatalysts. Advanced metal-free carbon-based oxygen reduction reaction (ORR) electrocatalysts are reviewed in combination with updates from studies in our laboratory, and the correlation between ORR activity and the electronic structure of sp 2 carbon materials is highlighted.