Electrode

Organic chemistry

Electrocatalyst

Transition metal

Catalysis

Physical chemistry

Inorganic chemistry

Aqueous solution

Chemistry

Metal

Oxygen reduction

Oxygen reduction reaction

Pyrolysis

Electrochemistry

Chemical Reviews

A comprehensive review of recent advances in the field of oxygen reduction electrocatalysis utilizing nonprecious metal (NPM) catalysts is presented. Progress in the synthesis and characterization of pyrolyzed catalysts, based primarily on the transition metals Fe and Co with sources of N and C, is summarized. Several synthetic strategies to improve the catalytic activity for the oxygen reduction reaction (ORR) are highlighted. Recent work to explain the active-site structures and the ORR mechanism on pyrolyzed NPM catalysts is discussed. Additionally, the recent application of Cu-based catalysts for the ORR is reviewed. Suggestions and direction for future research to develop and understand NPM catalysts with enhanced ORR activity are provided.

Nonprecious Metal Catalysts for Oxygen Reduction in Heterogeneous Aqueous Systems