Benzimidazoles are fundamental structural units in pharmaceuticals and agrochemicals, yet their conventional synthesis requires harsh conditions, including strong acids, elevated temperatures, and stoichiometric oxidants. These methods consume substantial energy and generate undesirable by-products, creating significant barriers to sustainable production. In recent years, photocatalytic systems powered by renewable solar energy have emerged as a promising green alternative for the synthesis of N‑heterocyclic compounds, enabling the efficient preparation of benzimidazoles under mild reaction conditions.
Among the various photocatalytic pathways developed for benzimidazole synthesis,the hydroxyethyl radical (•CH(CH3)OH) mediated pathway offers distinct advantages by avoiding the formation of aldehyde intermediates, thereby suppressing side reactions and improving product selectivity. However, its implementation faces a critical technical bottleneck in that selective activation and cleavage of the α‑C–H bond in ethanol, an essential prerequisite for the radical pathway, remains challenging due to the coexistence of competing O–H, C–O, and other C–H bonds within ethanol. Furthermore, the rapid recombination of photogenerated charge carriers in conventional photocatalysts further limits overall efficiency.
Recently, a research team led by Prof. Yi-Jun Xu, Prof. Zi-Rong Tang&Prof. Liang Maohas developed a high-performance photocatalytic system based on oxygen vacancy (VO)-rich Nb2O5 decorated with Pt nanoparticles (NPs). Their findings were published in the Chinese Journal of Catalysis (DOI: 10.1016/S1872-2067(26)64999-6).
The rationally designed Pt/Nb2O5-VO photocatalyst exhibits exceptional activity for the simultaneous synthesis of 2‑methylbenzimidazole (2MBZ)and hydrogen (H2)from ethanol and o‑phenylenediamine (OPD)under light irradiation. The optimal catalyst achieves the highest photocatalytic activity to date, with production rates of 4.0 mmol g⁻1 h⁻1 for 2MBZand 10.2 mmol g⁻1 h⁻1 for H2, respectively.
Systematic characterization and density functional theory calculations confirm that the enhanced performance originates from the synergistic interplay between VO and Pt NPs. The VOsites on the surface of Nb2O5serve as the primary active centersthatenhanceethanol adsorptionand selectively promote dehydrogenation to form •CH(CH3)OH radicals. Meanwhile, the Pt NPs function as electron sinks, enriching photogenerated electrons and facilitating efficient proton reduction to H2. Importantly, the synergy between VO and Pt NPs facilitates the separation and migration of photogenerated charge carriers. This dual functionality enables the reaction to proceed through the radical-mediated pathway, effectively bypassing the aldehyde intermediate and minimizing by-product accumulation.
The research team further verified the broad substrate compatibility of the Pt/Nb2O5-VO catalyst across various o-arylenediamines and alcohol derivatives, highlighting its potential for the selective synthesis of diverse benzimidazole derivatives. By integrating defect engineering with metal co‑catalyst modification, this work establishes a new paradigm for the rational design of advanced photocatalysts and provides a sustainable catalytic route for the concurrent production of high‑value N‑heterocyclic compounds and clean H2 fuel.
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 one journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.
At Elsevier http://www.journals.elsevier.com/chinese-journal-of-catalysis
Manuscript submission https://mc03.manuscriptcentral.com/cjcatal
