Monolayer HNb3O8 2D nanosheets have been used as highly chemoselective and active photocatalysts for the selective oxidation of alcohols. The nanosheets exhibit improved photocatalytic activity over their layered counterparts. Results of in situ FTIR, DRS, ESR, and DFT calculations show the formation of surface complexes between the Lewis acid sites on HNb3O8 2D nanosheets and alcohols. These complexes play a key role in the photocatalytic activity of the material. Furthermore, the unique structural features of the nanosheets contributed to their high photocatalytic activity. An electron transition from the coordinated alcohol species to surface Nb atoms takes place and initiates the aerobic oxidation of alcohols with high product selectivity under visible light irradiation. This reaction process is distinct from that of classic semiconductor photocatalysis.

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A monolayer HNb3O8 nanosheet was prepared. Its unique 2D structure promoted the efficient separation of the photo-generated carriers, leading to an enhanced photocatalytic hydrogen evolution.

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TaON nanoparticles with low surface reduction defect sites were successfully constructed by a simple nitridation approach using Ta2O5·nH2O as a precursor. Large amounts of crystal water in Ta2O5·nH2O are considered as a parclose to prohibit Ta(5+) from being reduced in the nitridation process with NH3 gas. Urea was also used in the synthesis, acting as a co-nitridation agent together with NH3 but also as a porogen for creating nanopores in TaON frameworks. The as-prepared TaON catalyst was evaluated by environmental purification of organic pollutants in water, as exemplified here by mineralization of phenol and its chloroderivatives in aqueous phase under visible light irradiation. Results revealed that a lower defect density of TaON, as well as its nanopore structure and smaller particle size, contribute to the promotion in both electron-hole separation and interfacial charge-transfer in materials surface/interface, being the main reasons for the enhanced photocatalytic performance.