Tungsten trioxide (WO3) displays excellent performance in solar-related material applications. However, this material is rare and expensive. Therefore, developing efficient materials using smaller amounts of WO3 is inevitable. In this study, we investigated how to create high photocatalytic performance of WO3 particles containing platinum (Pt, as a co-catalyst) and homogeneously spherical macropores (as a medium to enable access of large molecules and light penetration into the remote internal regions of the catalyst). The present particles were prepared by spray drying of a precursor solution containing WO3 nanoparticles, Pt solution, and polystyrene (PS) spheres (as a colloidal template). Photocatalytic studies showed that changes in particle morphology (from dense with smooth surfaces, to dense with rough surfaces, to porous structures) and added Pt effectively improved the photocatalytic performance over WO3 nanoparticles. Our results showed that the best precursor (prepared using a PS/WO3 mass ratio of 0.32 and containing Pt co-catalyst) provided WO3 particles with a photocatalytic rate of more than 5 times that of pure 10 nm WO3 nanoparticles. Moreover, the catalyst can be effectively recycled without an apparent decrease in its photocatalytic activity. The experimental results were also supported by a proposal mechanism of the photocatalytic reaction phenomenon.
Keywords: macroporous structure; nanoparticle; self-organization; submicron; surface activation; visible light irradiation.