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Mesoporous silica KIT-6 with different pore sizes was controllably synthesized by hydrothermal methods.The same contents of Pt were loaded on KIT-6 supports to apply for propane total oxidation.Low-angle X-ray diffraction (XRD),nitrogen adsorption-desorption,CO chemisorption and transmission electron microscopy (TEM) were carried out to investigate the physicochemical properties of the catalysts.The results reveal that different pore sizes of KIT-6 supports could affect the Pt particle sizes on KIT-6.The mesopores on KIT-6-80 and KIT-6-130 effectively confine the size of the inside Pt nanoparticles during calcining.Pt/KIT-6-80 with the appropriate pore size as well as the Pt particle size exhibits the best catalytic performance with T50 (the temperature at which hydrocarbon (HC) conversion reaches 50％) of only 237 ℃.However,Pt particles prefer dispersing on the extal surface of KIT-6-40 due to those too small pores.