Catalytic Performance and Mechanistic Study of Toluene Combustion over the Pt-Pd-HMS Catalyst

Abstract Pt-Pd-HMS catalyst had been prepared by a one-pot approach and tested for toluene combustion. Comparing with conventional impregnated Pt-Pd/HMS ( E a = 111.41 kJ/mol, Pt-Pd particle size = 23.4 nm), the Pt-Pd-HMS exhibited lower activation energy ( E a = 80.23 kJ/mol) and smaller Pt-Pd particle size (6.3 nm). Moreover, surface Pt 0 /Pt total of the Pt-Pd-HMS (52.8%) was higher than that of the Pt-Pd/HMS (46.8%), and Pt-Pd-HMS obtained an optimal catalytic performance with T 90 = 179 o C at a GHSV = 26,000 mL/(g·h). In-situ DRIFTS indicated that simultaneous generation of benzoate species and aliphatic compounds as intermediates occurred on the active sites of Pt-Pd-HMS. In contrast, the intermediates of toluene combustion on the active sites of Pt-Pd/HMS were dominated by benzoates.