Dissolution of alkali metal dopant in flame-made Pt/Na_x-Al_2O_3 catalysts: enhanced benzene catalytic oxidation property and activation mechanism

摘要

This paper presented an efficient way to improve loading and dispersion of Pt on Al_2O_3 support prepared by flame spray pyrolysis (FSP). Soluble alkali metal salt (NaNO_3 in this case) was chosen as the dopant in Pt/Al_2O_3 and was washed to remove after direct preparation. Catalytic oxidation of benzene was carried out in order to test the property of the catalysts. Washed samples showed enhanced catalytic property and stability. The promotion could be attributed to the increase of loading and dispersion of Pt. Moreover, surface active hydroxyl groups also played an important role in the catalytic reaction which also increased after the dissolution of NaNO_3. This facile strategy could be applied to a large range of noble metal supported catalysts prepared by FSP method.