High-performance of plasma-catalysis hybrid system for toluene removal in air using supported Au nanocatalysts

Abstract

Removal of toluene from indoor air using gold (Au) nanocatalysts suffers from relatively low activity and gradual catalyst deactivation under mild conditions due to the difficultly activated benzene series. We reported here that this challenge can be tackled with a plasma-catalysis hybrid system constructed by packing supported Au/CeO2/Al2O3 nanocatalysts into discharge region. This hybrid system could completely remove toluene with above 90% CO2 selectivity and greatly reduced concentration of poisonous byproducts (O3 and NOx) at 1500 J/L, while exhibiting good humidity tolerance and superior stability. The combination of Au nanocatalysts with plasma possesses relatively uniform discharge mode for generating large numbers of reactive species, removing organic intermediates from catalyst surface at low temperatures, and suppressing the formation of secondary pollutants and the poisoning of Au nanocatalysts. Furthermore, the strong interaction of Au nanoparticles with CeO2 effectively alleviates the coarsening phenomenon of Au nanocatalysts during the plasma-catalysis process and creates more oxygen vacancies for efficient oxidation of toluene into CO2 under the action of plasma. The high-performance plasma-catalysis hybrid system packed with supported Au/CeO2/Al2O3 nanocatalysts offers a promising approach to use the highly active Au-based nanocatalysts for refractory VOCs removal at low temperatures.