Au/Rod-like MnO2 catalyst via thermal decomposition of manganite precursor for the catalytic oxidation of toluene

Abstract

Au/Rod-like MnO2 catalyst was prepared via thermal decomposition of Au/MnOOH precursor. Au nanoparticles (NPs) with an average size of about 3.05 nm were highly dispersed on the MnOOH supports. Au/MnO2-300 catalyst exhibited the best catalytic activity for toluene oxidation due to the abundant surface Mn4+ species, large specific surface area, good low-temperature reducibility and high oxygen species mobility. The further increase of thermal decomposition temperature resulted in the severe sintering of Au NPs, causing the decrease of toluene catalytic activity. The T50 and T90 values for Au/MnO2-300, 400 and 500 catalysts were 202, 207, 210 °C and 205, 210, 215 °C, respectively. The apparent activation energy of Au/MnO2-300 catalyst (61 kJ/mol) was obviously lower than those of Au/MnO2-400 (107.8 kJ/mol) and 500 (141.5 kJ/mol) catalysts. The reaction rates at 185 °C had a decrease tendency from 0.37 to 0.16 mol s−1 gcat−1 with the growth of Au NPs for Au/MnO2-300, 400 and 500 catalysts.