Structure Effects of Metal Corroles on Energy-Related Small Molecule Activation Reactions

Abstract

The increasing global energy and environmental crises make it urgent to find and use renewable, clean, and environmentally benign new energy resources. New energy conversion schemes based on small molecule activation reactions, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR), have been proposed. For example, catalytic water splitting provides a promising way to convert solar energy to chemical energy, which is stored as the hydrogen fuel. Hydrogen oxidation in fuel cells is an energy-releasing process to generate electric energy and water as the only product. Although such a hydrogen-based new energy scheme is appealing, its viability is dependent on highly efficient and robust catalysts for these small molecule activation reactions. Recently, a variety of metal corroles have been demonstrated to be efficient in catalyzing HER, OER, and ORR. The redox-active trianionic corrole ligands can afford a rigid four-coordinated square-planar molecular structure and are very effective in stabilizing high-valent metal centers. These features make metal corroles very attractive to serve as catalysts for these processes. More importantly, the structure of metal corroles can be systematically modified, which provides an ideal system to investigate the structure–reactivity relationship with aims to obtain fundamental knowledge on catalyst design and also catalytic mechanism. In this review, we summarize recently reported metal corrole catalysts for HER, OER, and ORR, as well as pay particular attention to the structure effects on these reactions.