Arrays of Au–TiO2 Janus-like nanoparticles fabricated by block copolymer templates and their photocatalytic activity in the degradation of methylene blue

A simple approach towards the fabrication of an array of Au–titania Janus-like nanoparticles is presented. Monolayer organic–inorganic hybrid films are produced by spin coating the mixture of polystyrene-block-poly (ethylene oxide) (PS-b-PEO)/HAuCl4 solution and titania sol–gel precursor solution. HAuCl4 and titania are incorporated in the PEO domains. After removing the organic matrix by deep UV irradiation, arrays of Au–TiO2 Janus-like nanoparticles on the substrate surface are obtained. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements are employed to characterize the Janus-like nanoparticles. The photocatalytic degradation of methylene blue (MB) chosen as the test reaction to examine the photocatalytic activity of the Au–TiO2 Janus-like nanoparticles is shown to be more effective as compared to that of TiO2 nanoparticles or Au–TiO2 composite nanoparticles. The increased photocatalytic activity of Au–TiO2 Janus-like nanoparticles is attributed to the Au–TiO2 heterointerfaces.