Microwave Assisted Synthesis of Au/TiO2 Catalyst for Photocatalysis and Oxidation Processes

Abstract

Heterogeneous catalysis using supported metal nanoparticles has attracted tremendous interest for applications including photocatalysis and selective oxidations. This work focuses on synthesis and characterization of Au nanoparticles supported on TiO2 (Au/TiO2), which exhibits unique photocatalytic and catalytic properties arising from quantum and plasmonic effects of Au as well as strong metal-support interactions. A facile microwave-assisted polyol approach was used to prepare Au/TiO2 with 0.1-3 wt% Au loading. Structural characterization by XRD revealed anatase TiO2 support was retained after Au deposition. Au particle size increased from sub nm clusters at 0.1 wt% to 13.5 nm nanoparticles at 3 wt% loading, demonstrating tunable nanoparticle dimensions. CO oxidation testing showed highest mass activity for 0.5 wt% Au/TiO2, with declining performance at higher loadings attributed to loss of low-coordination sites through agglomeration. Photocatalytic degradation of methyl orange dye was most efficient with 0.5 wt% Au/TiO2 under simulated solar irradiation. The higher photoactivity is ascribed to improved visible light harvesting and minimized charge recombination from uniform deposition of small plasmonic Au nanoparticles. The results demonstrate optimized Au loading and dispersion governs both catalytic and photocatalytic efficiency of Au/TiO2 synthesized via microwave polyol method.