Metal-doped polyoxometalates with dual ligands for efficient CO2 photoreduction

Abstract

The design of highly active photocatalysts for carbon dioxide reduction is of far-reaching significance for the mitigation of industrial exhaust pollution and the promotion of sustainable development. In this work, three catalysts containing dual ligands and doped with metal V, [Co(DAPSC)(H₂O)₂]₂[Co(H₂O)₅]_0.5[PW₁₁CoO₃₉(Hdatrz)]·3.5H₂O (1), (H₂bim)[Co(DAPSC)(bim)(H₃PW₁₀V^IV₂O₄₀)]·4H₂O (2), and [Co(DAPSC)(bbi)(H₂O)]₂(PW_11.5V^IV_0.5O₄₀)·4H₂O (3) [DAPSC = 2,6-diacetylpyridine bis-(semicarbazone), Hdatrz = 3,5-diamino-1,2,4-triazole, bim = bis(1-imidazolyl)methane, and bbi = 1,1′-(1,4-butanediyl)bis(imidazole)], have been successfully synthesized under hydrothermal conditions. A systematic exploration was undertaken to characterise the structures and photocatalytic transformations. The results of both the IR and EDS tests indicated the successful doping of V atoms. The photocatalytic CO₂ reduction exploration demonstrated that all catalysts modified with dual ligands exhibited high photocatalytic activity. The results therein revealed that catalyst 2 exhibited the most efficient photocatalytic performance in the reduction of carbon dioxide using visible light. Under optimal conditions, the CO yield reached 11 003.3 μmol g⁻¹ h⁻¹ and maintained good catalytic activity after five cycles, outperforming the majority of the reported heterogeneous POM-based photocatalysts. The present study proves that the additional doping of the transition metal vanadium into catalysts based on dual ligands downstream contributes to the development of highly active photocatalysts for CO₂ reduction.