3d-Metal Oxide Nanostructures for Oxygen Electrocatalysis

Recent advances in the development of clean energy sources over the past few years have marked a new era in electrocatalysis. This clean energy source holds the potential to be used in proton-exchange membrane fuel cells. Oxygen electrocatalysis is the most important overall reaction that takes place inside a fuel cell (FC). Oxygen electrocatalysis is the combination of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Both of these reactions are very complicated but of great practical importance. However, these reactions need a catalyst to make their application feasible. The precious metals platinum and iridium are used as benchmark catalysts for the ORR and OER, respectively. This chapter focuses on designing different 3 d -metal oxides (e.g., oxides of copper, iron, manganese, and cobalt) as capable alternatives to precious metals for enhanced oxygen electrocatalysis. It provides insight into the numerous unique aspects of novel metal oxides in oxygen electrocatalysis. The fabrication of various electrocatalysts with different compositions and structures is also highlighted. The performances of 3 d -metal oxides are compared with those of the benchmark electrocatalysts. The enhancement of activity through the formation of mixed oxides and hybrid materials with various supports is elaborated. Diverse structures of metal oxides along with their electrochemical capabilities identify these materials as alternative electrocatalysts for various FC reactions.