Formaldehyde oxidation on silica-supported Pt catalysts: The influence of thermal pretreatments on particle formation and on oxidation mechanism

Abstract In this work, thermal treatment of 0.2 wt.% Pt 4+ deposited on SiO 2 through vacuum calcination and H 2 reduction is used to synthesize Pt particles less than 1 nm in diameter that are uniformly dispersed on the SiO 2 . Traditional treatments involving air calcination/H 2 reduction on the same 0.2 wt.% Pt 4+ /SiO 2 result in the formation of inhomogeneous Pt particles with an average size of ∼8.4 nm. The tiny Pt particles have an improved reaction rate at ambient temperature and better catalytic stability for formaldehyde (HCHO) oxidation. The formation mechanism of tiny Pt particles and the reaction mechanism of HCHO oxidation were investigated. The CO decomposition product from HCHO could be the essential intermediate in the course of HCHO oxidation, and the oxidative reaction pathway should be HCHO → CO → CO 2 . Adsorbed HCHO may bond to the Pt surface in the η 2 configuration and form CO through a decomposition process.