Size-controllable Pt nanoparticles ranging from 1.3 to 2.3 nm were successfully loaded onto ZSM-5 (Pt-x/ZSM-5, where x is the mean diameter of the Pt nanoparticles). Catalytic tests in complete oxidation of toluene as a model for VOC removal show that Pt-1.9/ZSM-5 has the highest activity, due to a balance of Pt dispersion and Pt⁰ proportion.