Concurrent catalytic removal of typical volatile organic compound mixtures over Au-Pd/α-MnO2 nanotubes.

α-MnO 2 nanotubes and their supported Au-Pd alloy nanocatalysts were prepared using hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Their catalytic activity for the oxidation of toluene/ m -xylene, acetone/ethyl acetate, acetone/ m -xylene and ethyl acetate/ m -xylene mixtures was evaluated. It was found that the interaction between Au-Pd alloy nanoparticles and α-MnO 2 nanotubes significantly improved the reactivity of lattice oxygen, and the 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst outperformed the α-MnO 2 nanotube catalyst in the oxidation of toluene, m -xylene, ethyl acetate and acetone. Over the 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst, (i) toluene oxidation was greatly inhibited in the toluene/ m -xylene mixture, while m -xylene oxidation was not influenced; (ii) acetone and ethyl acetate oxidation suffered a minor impact in the acetone/ethyl acetate mixture; and (iii) m -xylene oxidation was enhanced whereas the oxidation of the oxygenated VOCs (volatile organic compounds) was suppressed in the acetone/ m -xylene or ethyl acetate/ m -xylene mixtures. The competitive adsorption of these typical VOCs on the catalyst surface induced an inhibitive effect on their oxidation, and increasing the temperature favored the oxidation of the VOCs. The mixed VOCs could be completely oxidized into CO 2 and H 2 O below 320°C at a space velocity of 40,000 mL/(g·hr). The 0.91 wt.% Au 0.48 Pd/α-MnO 2 nanotube catalyst exhibited high catalytic stability as well as good tolerance to water vapor and CO 2 in the oxidation of the VOC mixtures. Thus, the α-MnO 2 nanotube-supported noble metal alloy catalysts hold promise for the efficient elimination of VOC mixtures. [ABSTRACT FROM AUTHOR]