Au/3DOM Co3O4: highly active nanocatalysts for the oxidation of carbon monoxide and tolueneElectronic supplementary information (ESI) available. See DOI: 10.1039/c3nr04126c

Three-dimensionally ordered macroporous Co 3 O 4 (3DOM Co 3 O 4 ) and its supported gold ( x Au/3DOM Co 3 O 4 , x = 1.1-8.4 wt%) nanocatalysts were prepared using the polymethyl methacrylate-templating and bubble-assisted polyvinyl alcohol-protected reduction methods, respectively. The 3DOM Co 3 O 4 and x Au/3DOM Co 3 O 4 samples exhibited a surface area of 22-27 m 2 g −1 . The Au nanoparticles with a size of 2.4-3.7 nm were uniformly deposited on the macropore walls of 3DOM Co 3 O 4 . There were good correlations of oxygen adspecies concentration and low-temperature reducibility with catalytic activity of the sample for CO and toluene oxidation. Among 3DOM Co 3 O 4 and x Au/3DOM Co 3 O 4 , the 6.5Au/3DOM Co 3 O 4 sample performed the best, giving a T 90% (the temperature required for achieving a conversion of 90%) of −35 °C at a space velocity of 20 000 mL g −1 h −1 for CO oxidation and 256 °C at a space velocity of 40 000 mL g −1 h −1 for toluene oxidation. The effect of water vapor was more significant in toluene oxidation than in CO oxidation. The apparent activation energies (26 and 74 kJ mol −1 ) over 6.5Au/3DOM Co 3 O 4 were lower than those (34 and 113 kJ mol −1 ) over 3DOM Co 3 O 4 for CO and toluene oxidation, respectively. It is concluded that the higher oxygen adspecies concentration, better low-temperature reducibility, and strong interaction between Au and 3DOM Co 3 O 4 were responsible for the excellent catalytic performance of 6.5Au/3DOM Co 3 O 4 . 1.1-8.4 wt% Au/3DOM Co 3 O 4 prepared by PMMA-templating and PVA-protected reduction methods show excellent catalytic performance for CO and toluene oxidation.