Recent progress in heteroatom doped carbon based electrocatalysts for oxygen reduction reaction in anion exchange membrane fuel cells

Oxygen reduction reaction (ORR) is a key step in many electrochemical devices such as fuel cells and metal-air batteries. However, the reaction proceeds at a significant overpotential requiring Pt-based catalysts. The scarcity and economical challenges associated with Pt is one of the major limitations for the commercialization of the devices. In this context, the electrochemical research community is constantly exploring other low-cost and earth -abundant materials as ORR catalysts. Carbon nanomaterials are identified as promising electrocatalysts due to their superb electronic conductivity together with high specific surface area. However, the low reactivity of carbon is the major limiting factor in the fabrication of ORR catalysts. Recent studies have proved that chemical modification of the carbon network (substitution of foreign atoms, Ex: N, S, B, F, P) could alter the reactivity of carbon nanomaterials for ORR. Many doping strategies have been proposed including single atom doping, co-doping and multi-atom doping. The heteroatom doped carbons have delivered promising results towards ORR in alkaline media. This review presents a rational approach of doping methods and the electrochemical properties of heteroatom doped carbons, and we believe that this review could be a guiding material to design advanced non-noble catalysts for ORR in the coming future. (c) 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).

Automated summary

Oxygen reduction reaction (ORR) is a crucial process in various electrochemical devices, but it requires Pt-based catalysts due to significant overpotential. However, the scarcity and cost of Pt hinder the commercialization of these devices. Consequently, researchers are exploring low-cost and abundant materials such as carbon nanomaterials as alternative ORR catalysts. Recent studies have shown that chemical modification of carbon nanomaterials through doping with foreign atoms (e.g., N, S, B, F, P) can enhance their reactivity for ORR. This review comprehensively discusses different doping strategies and the electrochemical properties of heteroatom-doped carbons, aiming to guide the development of advanced non-noble catalysts for ORR.