The Effect of Annealing Treatment and Atom Layer Deposition to Au/Pt Nanoparticles-Decorated TiO2 Nanorods as Photocatalysts

The wide band gap of TiO2 hinders the utilization of visible light in high-performance photocatalysis. Herein, vertically aligned Ti nanopillar arrays (NPAs) were grown by the glancing angle deposition method (GLAD) and then thermally oxidized into TiO2 NPAs. The metallic nanoparticles (NPs) were fabricated by successive ion layer adsorption and reaction (SILAR) method. And we covered ultrathin TiO2 layer on Au/Pt NPs decorated NPA using atomic layer deposition (ALD) method and did annealing process in the end. The photoelectrochemical (PEC) performance and dye degradation have been studied. We find the dye degradation efficiency of best combination reaches up to 1.5 times higher than that of original Au/Pt-TiO2 sample under visible light irradiation. The TiO2 ALD layer effectively protects the nanostructure from corrosion and helps the transmission of electrons to the electrolyte. By controlling the annealing temperature we could achieve a matched band gap due to change in noble metal particle size. Our work demonstrates that rational design of composite nanostructures enhances the usage of broader wavelength range light and optimizes photocatalytic degradation of organic pollutants in practical applications