Pt-support interaction and nanoparticle size effect in Pt/CeO_2-TiO_2 catalysts for low temperature VOCs removal

摘要

A series of Pt/CeO2-TiO2 catalysts (0.5 wt% Pt) with size-controllable Pt nanoparticles were prepared by a modified ethylene glycol reduction method and the Pt particle size effect of Pt/CeO2-TiO2 catalysts on benzene and 1,2-dichloroethane (DCE) degradation was investigated. It reveals that the metal-support interaction of PtOx species and CeO2-TiO2 mixed oxides is enhanced by the reduced Pt particle sizes. The formation of more Pt2+ species and stronger redox properties at low-temperature resulted by the enhanced metal-support interaction of Pt/CeO2-TiO2 catalysts both greatly promotes the deep oxidation for benzene and C2H3Cl byproduct during DCE degradation at low temperature. Pt/CeTi-11 with the smallest average Pt particle size (1.53 nm) exhibits the highest activity among all the catalysts for benzene degradation, with T-90(%) of only 152 degrees C (1000 ppm, GHSV = 15,000 h(-1)). However, more acidic sites (especially the strong acid) were formed on the Pt/CeO2-TiO2 catalysts with bigger Pt nanoparticle (2.95 nm), contributing to activate and convert DCE to C2H3Cl. More importantly, Pt/CeO2-TiO2 catalysts are extremely stable in DCE degradation reaction, and have been scarcely influenced by the presence of benzene and water in the feed gases. (C) 2020 Elsevier Ltd. All rights reserved.