Honeycombed Au@C-TiO2-Xcatalysts for enhanced photocatalytic mineralization of Acid red 3R under visible light.

The mineralization of organic pollutants under visible light is challenging, limiting the practical application of photocatalytic technology in wastewater treatment. To achieve the efficient mineralization of Acid red 3R (AR3R), a series of honeycombed catalysts (TiO2, C-TiO2-X, Au@TiO2 and Au@C-TiO2-X) were prepared via a facile in situ synthetic method and characterized by XRD, TEM, BET, XPS and DRS, respectively. The introduction of C and Au species promote the simultaneous generation of •O2- and •OH over Au@C-TiO2-X under visible light radiation. The Au@C-TiO2-X catalyst showed superior performance for the deep mineralization of AR3R, affording a TOC removal rate larger than 90 % within 240 min under visible light (> 420 nm). The photocatalytic degradation mechanism of AR3R is proposed according to UV-vis and in situ DRIFTS analysis. The superior photocatalytic activity of Au@C-TiO2-X is attributed to the synergistic effect of •O2- and •OH owing to C doping and Au deposition.