Visible light-induced enhanced photoelectrochemical and photocatalytic studies of gold decorated SnO2 nanostructures

This paper reports a novel one-pot biogenic synthesis of Au-SnO2 nanocomposite using electrochemically active biofilm. The synthesis, morphology and structure of the as-synthesized Au-SnO2 nanocomposite were in-depth studied and confirmed by UV-vis spectroscopy, photoluminescence spectroscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. It was observed that the SnO2 surface was decorated homogeneously with Au nanoparticles. The photoelectrochemical behavior of the Au-SnO2 nanocomposite was examined by cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and linear sweep voltammetry in the dark and under visible light irradiation. Visible light-induced photoelectrochemical studies confirmed that the Au-SnO2 nanocomposite had enhanced activities compared to the P-SnO2 nanoparticles. The Au-SnO2 nanocomposite was also tested for the visible light-induced photocatalytic degradation of Congo red and methylene blue, and showed approximately 10 and 6-fold higher photocatalytic degradation activity, respectively, compared to P-SnO2. These results showed that the Au-SnO2 nanocomposite exhibits excellent and higher visible light-induced photoelectrochemical and photocatalytic activities than the P-SnO2 nanoparticles, and can be used for a wide range of applications.