image: Read too many studies on single-atom (SA) catalysts on non-metallic supports? Here we give you an introduction of metal atoms atomically dispersed on an inorganic metal-based support and their applications in catalytic photoreduction reactions, including H2 evolution reaction, CO2 reduction reaction, and N2 reduction reaction. The different anchoring patterns of SA metals on metal-based supports provide the basis to achieve effective metal-support interactions and ensure the atomic distribution of the foreign SA metals. view more
Credit: Chinese Journal of Catalysis
Since the concept of single atom catalysts (SACs) was first clarified, SACs have been extensively developed and applied in efficient catalytic reactions, attributing to the various merits like maximized metal-utilization efficiency, intensive structural stability, high density of active sites, and superior catalytic activity and selectivity. In most cases, the supports are deliberately chosen to anchor atomically dispersed single-atom (SA) metals (M). Over the past decade, the support materials of SACs have been expanded from metal oxides to metal sulfides, metal nitrides, metal-organic frameworks (MOFs), and carbon-based materials (e.g., graphene, carbon nitride). Among them, embedding single-atom metals into metal-based supports would be an ideal choice to prepare high-performance photocatalysts, because metal-based supports are usually semiconductors or metal clusters, possessing unique features such as light-absorbing abilities, redox attributes, adjustable surface acidity/basicity, abundant surface binding sites, and active lattice anions.
Recently, a research team led by Prof. Shaobin Wang from The University of Adelaide reviewed the anchoring of SA metals on metal-based supports, which are essential to unravel the structure design principles of SACs. This minireview specialized on the applications of metal-based material supported SACs for critical photoreduction reactions to clean energy production, including hydrogen evolution reaction (HER), CO2 reduction reaction (CRR), and N2 reduction reaction (NRR), which all share the same water oxidation half-reaction to provide protons/electrons. Such a niche-targeting review technically on the metal-based material supported SACs for energy conversion by photoreduction reactions with the structure-property relationships has not been available so far. This critical review is hoped to portray the approaches regarding stabilizing active atomic metal sites on metal-based supports and intelligently regulating SA metal sites on metal-based supports to obtain photocatalysts with high activity, stability and selectivity for photocatalytic HER, CRR or NRR.
Single atoms can be fastened on various metal-based hosts via i) bonding with atoms (e.g., charged chalcogen/halogen anions, metal cations) on surface coordination-unsaturated sites (SCUS); ii) substituting surface atoms; iii) coordinating with bridging organic/inorganic functional groups on the surface; and iv) space-confined embedding on the surface. The different metal-support interaction patterns possess unique features of atom loading, properties, and tunability.
The applications of metal-based material-supported SACs are discussed for three critical photoreduction reactions, i.e., photocatalytic HER, CRR, and NRR. The contributions of isolated noble or non-noble SA metals and metal-support interaction to different catalytic reactions are emphasized to unravel the structure-activity relationships. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(21)63918-9).
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About the Journal
Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top two journals in Applied Chemistry with a current SCI impact factor of 12.92. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
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