Catalytic Oxidation Of Toluene With Low Loading Bimetallic Au@Pt Core-Shell Catalyst

Highly active bimetallic Au@Pt core-shell catalysts were prepared by using direct-adsorption method, in which uniformly dispersed Au@Pt nanoparticles synthesized using two-step liquid-phase hydrogen reduction method were directly loaded on support. The performance of the catalysts for catalytic oxidation of toluene was evaluated. The catalysts were characterized by transmission electron microscopy (TEM) in conjunction with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N-2 adsorption-desorption and temperature-programmed reduction (H-2-TPR). As a result, the bimetallic Au@Pt-core shell catalysts exhibited higher catalytic activity compared with monometallic Au or Pt catalyst, and the Au-1@Pt-2/Al2O3 core-shell catalyst showed outstanding catalytic activity, selectivity and stability among the bimetallic catalysts. The temperature for conversion of 98% toluene (T98) was 195 C under the condition of toluene volume fraction at 1 x10(-3) and the gas hourly space velocity of 18 L.g(-1).h(-1) XPS results illustrated that the enhancement of catalytic activity is attributed to the presence of Au underneath Pt shell where electron exchange from Au to Pt has promoted the formation of active oxygen species on Pt, which facilitates the oxidation of toluene. In addition, the active components of the catalyst mainly existed in the form of Au and Pt, and the strong interaction between the Au@Pt nanoparticles and the support was observed.