Au-Pd/3DOM Co3O4: Highly active and stable nanocatalysts for toluene oxidation

The polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction routes were adopted to prepared three-dimensionally ordered macroporous (3DOM) Co3O4 and its supported gold-palladium alloy (xAuPd/3DOM Co3O4, x = 0.50-1.99 wt% and Au/Pd mass ratio = 1:1) nanocatalysts. The 3DOM Co3O4 supported Au-Pd samples performed much better than supported single Au or Pd samples, with the 1.99AuPd/3DOM Co304 sample showing the best performance: the T-10%, T-50%, and T-90% (temperatures required for achieving toluene conversions of 10%, 50%, and 90%) were 145, 164, and 168 degrees C at a space velocity of 40,000 mL/(g h), respectively. The 3DOM Co3O4 supported Au-Pd nanocatalysts also exhibited better catalytic stability and more moisture-tolerant ability than the supported Au or Pd samples for toluene oxidation. The apparent activation energies (33-41 kJ/mol) over xAuPd/3DOM Co3O4 were much lower than those (52-112 kJ/mol) over 3DOM Co3O4 and supported single Au or Pd samples, with the 1.99AuPd/3DOM Co3O4 sample exhibiting the lowest apparent activation energy (33 kJ/mol). It is concluded that better oxygen activation ability and stronger noble metal-3DOM Co3O4 interaction were responsible for the excellent catalytic performance of 1.99AuPd/3DOM Co3O4. (C) 2014 Elsevier Inc. All rights reserved.