Preparation of highly dispersed metallic Pt nanoparticle catalysts for low-temperature propene combustion

Abstract

Propene (C₃H₆) combustion is crucial in emission-control applications. A set of Pt/γ-Al₂O₃ samples were synthesized through either the chemical reduction-deposition method (denoted as RD) or the incipient wetness impregnation method (denoted as IW) and employed for C₃H₆ combustion. By adjusting the synthesis conditions, Pt/γ-Al₂O₃ catalysts with diverse Pt nanoparticle size distributions were produced. Due to the reduction in particle size, the Pt-RD catalysts exhibited better catalytic activity than the Pt-IW catalysts. With an average Pt nanoparticle size of 2.93 nm, the 1% Pt-RD₃ catalyst exhibited optimal catalytic performance, with a complete C₃H₆ conversion at 110 °C. A higher proportion of Pt⁰ was confirmed to be beneficial to C₃H₆ combustion by X-ray photoelectron spectroscopy (XPS) investigations. Moreover, Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis demonstrated that Pt⁰ atoms at edge and corner surface sites participated in C₃H₆ oxidation as active sites. Extended experiments revealed that the 1% Pt-RD₃ catalyst exhibited strong tolerance against water and high oxidation reactivities of other pollutants in vehicle emission. This work provides an effective attempt toward synthesis and applications of Pt-based catalysts for hydrocarbons combustion.