Hualei Zhang,Qianying Lin,Shangbo Ning,Yangen Zhou,Huaxiang Lin,Jinlin Long,Zizhong Zhang,Xuxu Wang
Mesoporous Pt–Nb2O5 photocatalysts with high photocatalytic hydrogen production activity were synthesized by a one-step method. The mesoporous structure of the as-made samples was characterized by X-ray diffraction, N2 adsorption–desorption isotherms and transmission electron microscopy. Pt–Nb2O5 exhibited higher hydrogen production activity than pure Nb2O5 and 0.8-Pt–D–M–Nb exhibited the best photocatalytic activity. In addition, Pt–Nb2O5 synthesized by a one-step method exhibited higher photocatalytic hydrogen production activity than that prepared by an incipient wetness impregnation method; 0.8-Pt–D–M–Nb exhibits a H2 evolution rate of 9.79 mmol h−1 g−1, while 0.8-Pt–I–M–Nb2O5 exhibits a H2 evolution rate of 7.73 mmol h−1 g−1. The enhanced photocatalytic activity of Pt–Nb2O5 was predominantly attributed to the efficient separation of photoinduced electrons and holes.
The hydroxyethyl radical (•CH(CH 3 )OH)-mediated pathway, by avoiding the formation of aldehyde intermediates, constitutes a promising approach for the highly selective photocatalytic synthesis of benzimidazoles from ethanol and o -phenylenediamine. However, inefficient reactant adsorption and activation, as well as severe recombination of photogenerated charge carriers of traditional photocatalysts, impose a fundamental challenge for this reaction pathway. Herein, we construct an oxygen vacancy (V O )-rich Nb 2 O 5 decorated with Pt nanoparticles (NPs), which exhibits the highest photocatalytic activity to date, with production rates of 4.0 mmol g −1 h −1 for 2-methylbenzimidazole and 10.2 mmol g −1 h −1 for H 2 , respectively. The synergistic interaction between V O and Pt NPs markedly promotes the migration and separation of photogenerated charge carriers. The electron-accumulating Pt NPs drive efficient H 2 evolution through proton reduction, while the engineered V O sites enhance ethanol adsorption and selectively activate α-C–H bond cleavage to generate •CH(CH 3 )OH radicals, suppressing the accumulation of N-ethyl-2-methylbenzimidazole by-products inherent to conventional aldehyde-mediated reaction pathways, significantly facilitating the co-production of benzimidazoles and H 2 . This work achieves directional pathway regulation via rational design of semiconductor defects and metal co-catalysts, establishing a radical-mediated strategy for efficient and selective green synthesis of N-heterocyclic compounds.
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