Heteroatom-Doped Graphitic Carbon Catalysts for Efficient Electrocatalysis of Oxygen Reduction Reaction

The oxygen reduction reaction (ORR) plays an important role in renewable energy technologies, such as fuel cells and metal–air batteries. Along with the extensive research and development of nonprecious metal catalysts (NPMCs) to reduce/replace Pt for electrocatalytic reduction of oxygen, a new class of heteroatom-doped metal-free carbon catalysts has been recently developed, which, as alternative ORR catalysts, could dramatically reduce the cost and increase the efficiency of fuel cells and metal–air batteries. The improved catalytic performance of heteroatom-doped carbon ORR catalysts has been attributed to the doping-induced charge redistribution around the heteroatom dopants, which lowered the ORR potential and changed the O2 chemisorption mode to effectively weaken the O–O bonding, facilitating ORR at the heteroatom-doped carbon electrodes. Subsequently, this new metal-free ORR mechanism was confirmed by numerous studies, and the same principle has been applied to the development of various other eff...