Catalysis of a Single Transition Metal Site for Water Oxidation: From Mononuclear Molecules to Single Atoms

Abstract

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.201904037.Low-cost, nonprecious transition metal (TM) catalysts toward efficient water oxidation are of critical importance to future sustainable energy technologies. The advances in structure engineering of water oxidation catalysts (WOCs) with single TM centers as active sites, for example, single metallic molecular complexes (SMMCs), supported SMMCs, and single-atom catalysts (SACs) in recent reports are examined. The efforts made on these configurations in terms of design principle, advanced characterization, performances and theoretical studies, are critically reviewed. A clear roadmap with the correlations between the single-TM-site-based structures (coordination and geometric structure, TM species, support), and the catalytic performances in water oxidation is provided. The insights bridging SMMCs with SACs are also given. Finally, the challenges and opportunities in the single-TM-site catalysis are proposed.

Heterogenization of Molecular Water Oxidation Catalysts in Electrodes for (Photo)Electrochemical Water Oxidation

“…The development of highly active and efficient long-lasting WOCs would allow to efficiently couple the WO with reductive transformations (such as CO 2 or water reduction) in artificial photosynthetic devices. Therefore, an alternative approach to the utilization of homogeneous or heterogeneous systems is the immobilization (heterogenization) of molecular water oxidation catalysts (WOCs) together with photoredox catalysts or not on electrodes for (photo)electrochemical WO, which has attracted the interest of the community [28,30,31,55,56].…”

“…This strategy is very versatile since many groups can be incorporated to the ligand scaffolds of molecular WOCs to covalently anchor them to (photo)electrode surfaces [55,57,62]. Several molecular WOCs based on Ru, Fe, Co, Mn, Fe and Cu have been explored for (photo)electrochemical WO using this immobilization strategy onto electrode surfaces [39,43,56,[60][61][62]126,127].…”

Strategies for Electrochemically Sustainable H2 Production in Acid

“…[ 147 ] A typical example of O 2 evolution in nature is found in photosystem II, where the multinuclear Mn 4 O 4 clusters of CaMn 4 O 5 are the active center for water oxidation. [ 148 ] The Mn 4 Ca core is another active center for oxygen evolution. [ 149 ] To mimic these active centers with enhancement, various types of homogeneous catalysts have been designed, most of which are based on organometallic complexes with different metal‐organic ligand coordinations and ligand structures.…”

Heterogenization of Ionic liquid Boosting Electrochemical Oxygen Reduction Performance of Co3O4 Supported on Graphene Oxide

“…[11][12][13] Earth-abundant transition metal-based materials have received extensive attentions for a couple of electrochemical applications. [14][15][16] For example, cobalt as an abundant metal has been widely explored as water oxidation and proton reduction catalysts, [17][18] while, for ORR, Co oxides such as Co 3 O 4 generally exhibit poor activity. [19] In this context, continuous attentions have been given to boost catalytic performance of Co 3 O 4 for ORR.…”