Indexed on: 05 Jun '16Published on: 02 Jun '16Published in: Catalysis Today
Three-dimensionally ordered macroporous CoCr2O4 (3DOM CoCr2O4) and its supported Au–Pd alloy (xAuPdy/3DOM CoCr2O4; x = 0.98 and 1.93 wt%; Pd/Au molar ratio (y) = 1.93–1.96) nanocatalysts were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of a number of techniques, and their catalytic activities were evaluated for methane combustion. The 3DOM CoCr2O4 and xAuPdy/3DOM CoCr2O4 samples possessed a high-quality 3DOM structure and a surface area of 33–36 m2/g. The Au–Pd alloy nanoparticles (NPs) with an average size of 3.3 nm were uniformly dispersed on the surface of the samples. The 1.93AuPd1.95/3DOM CoCr2O4 sample showed the best catalytic performance: the T10%, T50%, and T90% (temperatures required for achieving methane conversion of 10, 50, and 90%, respectively) were 305, 353, and 394 °C at a space velocity (SV) of 20,000 mL/(g h). The effects of SV, water vapor, and sulfur dioxide on the catalytic activity of the 1.93AuPd1.95/3DOM CoCr2O4 sample were also examined. It is concluded that the excellent catalytic performance of 1.93AuPd1.95/3DOM CoCr2O4 was associated with the higher surface area and adsorbed oxygen species concentration, better low-temperature reducibility, and strong interaction between Au–Pd alloy NPs and 3DOM CoCr2O4.