Emerging Multifunctional Single-Atom Catalysts/Nanozymes

Abstract

Single-atom catalysts (SACs), in which the metal active sites are isolated on the support and stabilized by coordinated atoms such as oxygen, nitrogen, sulfur, etc., represent the maximum usage efficiency of the metal atoms. Benefiting from the recent progress in synthetic strategies, characterization methods, and computational models, many SACs that deliver an impressive catalytic performance for a variety of reactions have been developed. The catalytic selectivity and activity are critical issues that need to be optimized and augmented in the areas of nanotechnology and biomedicine. This review summarizes some recent experimental and theoretical progress aimed at clarifying the structure of SACs and how they influence the catalytic performance. The examples described here elaborate on the utility of SACs and highlight the strengths of these catalysts in the applications of biomedicine, environmental protection, and energy conversion. Finally, some current challenges and future perspectives for SACs are also discussed.

Single-Atom Photocatalysts for Emerging Reactions

“… 43 , 44 Single-atom photocatalysts have attracted tremendous attention primarily owing to the following fascinating benefits in comparison to the nanoclusters, nanoparticles, and bulk counterparts: (i) exceptionally high activity and selectivity originating from their distinct electronic structures and unsaturated coordination centers; 45 , 46 (ii) tremendous reduction in the usage of catalytic metals achieved by their atomic dispersion; 47 , 48 (iii) easy to follow reaction mechanisms because of single-atom reactive sites; 49 , 50 and (iv) an excellent platform to apprehend the structure–performance correlation based on their atomic-level structures. 51 − 53 The metal–support interactions are crucial for maintaining the stability of single-atom-based photocatalysts, where metal atoms are usually stabilized by neighboring surface atoms or ligands on the support, thus preventing the diffusion and aggregation of the well-dispersed metal single atoms. 43 , 54 − 56 A universal strategy for designing and fabricating single-atom-based photocatalysts is to strengthen the effect of the metal–support interaction on single-atom photocatalysts.…”

Single‐Atom Catalysts: A Sustainable Pathway for the Advanced Catalytic Applications

“…[171] This opened a great opportunity for the researchers to solve this issue by developing other metal-based SACs. [172] Luo et al developed chromium (Cr)-N 4 sites for ORR catalytic activity in an acidic medium. [147] Cr-N 4 catalyst exhibits a half-wave potential of 0.773 V and interestingly, Fenton reaction is substantially reduced (checked by the 2,20-azinobis-(3-ethylbenzthiazoline-6-sulfonate) and possesses high stability.…”

“…[ 171 ] This opened a great opportunity for the researchers to solve this issue by developing other metal‐based SACs. [ 172 ] Luo et al. developed chromium (Cr)–N 4 sites for ORR catalytic activity in an acidic medium.…”

Recent Advances on Transition Metal Dichalcogenides for Electrochemical Energy Conversion

“…[ 13,14 ] Particularly, in the post‐graphene era, transition metal dichalcogenides (TMDCs) are conceivably one family of the most popular 2D layered materials due to their intriguing properties and wide applications in electrochemical energy‐related fields. [ 15–17 ] The metal atom in each monolayer is sandwiched between two chalcogens, giving rise to the stoichiometric MX 2 with M as the transition‐metal element and X as the chalcogen species, such as S, Se, or Te. [ 18–20 ] As demonstrated, there exist multiple phases within the family of TMDCs, including the thermodynamically stable 2H phase with trigonal prismatic configuration and the metastable 1T/T´ phase with octahedral geometry.…”