MXenes as noble-metal-alternative co-catalysts in photocatalysis

• Published in: Chinese journal of catalysis 2021-01, Vol.42 (1), p.3-14
• Main Authors: Li, Kaining, Zhang, Sushu, Li, Yuhan, Fan, Jiajie, Lv, Kangle
• Format: Article
• Language: English
• Subjects: CO2 reduction; Hydrogen production; MXenes; Nitrogen fixation; Photocatalytic degradation
• ISSN: 1872-2067; 1872-2067
• DOI: 10.1016/S1872-2067(20)63630-0

Photocatalysis has become a focal point in research as a clean and sustainable technology with the potential to solve environmental problems and energy crises. The loading of noble-metal co-catalysts can substantially improve the photocatalytic efficiency of semiconductors. Because the high cost and scarcity of noble metals markedly limit their large-scale applications, finding a noble-metal-alternative co-catalyst is crucial. MXene, a novel 2D transition metal material, has attracted considerable attention as a promising substitute for noble metal co-catalysts owing to its cost-efficiency, unique 2D layered structure, and excellent electrical, optical, and thermodynamic properties. This review focuses on the latest advancements in research on MXenes as co-catalysts in relatively popular photocatalytic applications (hydrogen production, CO2 reduction, nitrogen fixation, and organic pollutant oxidation). The synthesis methods and photocatalytic mechanisms of MXenes as co-catalysts are also summarized according to the type of MXene-based material. Finally, the crucial opportunities and challenges in the prospective development of MXene-based photocatalysts are outlined. We emphasize that modern techniques should be used to demonstrate the effects of MXenes on photocatalysis and that the photocatalytic activity of MXene-based photocatalysts can be further improved using defective engineering and recent phenomena such as the localized surface plasmon resonance effect and single-atom catalysis. This mini-review presents recent achievements in research on MXenes as co-photocatalysts in H2 production, CO2 reduction, N2 fixation, and organic degradation. The structures, synthesis, and mechanisms of MXenes as co-photocatalysts are also summarized and discussed.