Construction of QuO/α-NaO-CoPc-functionalised UiO-66-NH2 and its mechanism for efficient synergistic photocatalytic mineralisation of Congo Red

In this study, quinolinoxy cobalt phthalocyanine (QuOCoPc) and naphthoxy cobalt phthalocyanine (α-NaOCoPc) were synthesised. Two novel composite photocatalysts, QuOCoPc@UiO-66-NH2 and α-NaOCoPc@UiO-66-NH2, were prepared by loading the respective phthalocyanines onto UiO-66-NH2 by an impregnation method. The samples were characterised using techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Using visible light as the light source and Congo Red (CR) solution as the target pollutant, the photocatalytic properties of the two composite materials were investigated. The results demonstrated that both composite catalysts exhibited excellent photocatalytic performance. Compared with the individual components QuOCoPc, α-NaOCoPc and UiO-66-NH2, the composites showed significantly enhanced catalytic degradation of CR. The degradation efficiencies of QuOCoPc@UiO-66-NH2 and α-NaOCoPc@UiO-66-NH2 reached 95.9 and 84.9% respectively. These findings indicate a strong synergistic effect between the phthalocyanines and UiO-66-NH2, with hydroxyl radicals (˙OH) and superoxide radicals (˙O2−) playing crucial roles as the primary active species.