Au/3DOM La0.6Sr0.4MnO3: Highly active nanocatalysts for the oxidation of carbon monoxide and toluene

Three-dimensionally ordered macroporous (3DOM) La0.6Sr0.4MnO3 (LSMO) and its supported gold (xAu/LSMO, x = 3.4–7.9 wt%) catalysts were prepared using the polymethyl methacrylate-templating and gas-bubble-assisted polyvinyl alcohol-protected reduction methods, respectively. There were good correlations of surface-adsorbed oxygen species concentration and low-temperature reducibility with the catalytic activity of the sample for CO and toluene oxidation. Among the LSMO and xAu/LSMO samples, 6.4Au/LSMO performed the best, giving T50% and T90% values of −19 and 3 °C for CO oxidation and 150 and 170 °C for toluene oxidation, respectively. The apparent activation energies (31–32 and 44–48 kJ/mol) obtained over xAu/LSMO were much lower than those (45 and 59 kJ/mol) obtained over LSMO for the oxidation of CO and toluene, respectively. It is concluded that higher oxygen adspecies concentration, better low-temperature reducibility, and strong interaction between Au and LSMO are responsible for the excellent catalytic performance of 6.4Au/LSMO.