Highly effective photocatalytic decomposition of tetracycline and reduction of Cr(VI) under visible light using Ag/polyoxometalate composite nanomaterials prepared by a mild grinding method

With environmental issues gaining increasing attention, the demand for developing economical and reusable catalysts has become increasingly critical. Although precious metal catalysts are effective in photocatalytic pollutant decomposition and Cr(VI) reduction, their high price, instability, and recovery difficulty constrain their application. This study introduces an approach where Ag + ions are exchanged with cations in polyoxometalate (POM) via a mild grinding method, followed by in situ illumination under ultraviolet light to produce Ag/Ag-POM composite nanomaterials. Upon interaction with POM clusters, Ag + ions are reduced to Ag nanoparticles, which enhances visible light absorption in the composite, thereby improving its photocatalytic efficiency. Ag/Ag-POM nanomaterials obtained from this process exhibit efficient and stable catalytic performance, efficiently degrading tetracycline (TC) and reducing hexavalent chromium (Cr(VI)) under visible light (λ > 420 nm). Especially, the Ag/AgHPMo 11 V composite demonstrated superior catalytic performance, achieving degradation efficiencies of 99.9% for 40 mg·L −1 TC. Moreover, it also exhibited efficient photoreduction of Cr(VI), achieving a reduction rate of 62.81% for 80 mg·L −1 Cr(VI) in a 100 mL solution using just 10 mg of the catalyst within 40 min of visible-light exposure. This research highlights the potential of polyoxometalate-based catalysts in the photocatalytic treatment of pollutants.