Efficient catalysts of supported PtPd nanoparticles on 3D ordered macroporous TiO2 for soot combustion: Synergic effect of Pt-Pd binary components

Abstract

The efficient nanocatalyst of three-dimensionally ordered macroporous (3DOM) TiO2-supported Pt-Pd nanoparticles (PtPd/3DOM-TiO2) was easily fabricated by method of the gas bubbling-assisted membrane reduction (GBMR). The catalyst shows well-defined ordered macroporous nanostructure with the average pore size of 280 nm, and hemispherical PtPd nanoparticles (NPs) with mean particle size of 3.6 nm are well dispersed and deposited on the inner walls of 3DOM-TiO2 support. 3DOM nanostructure can improve the contact efficiency between soot particles and catalysts, and enhances the mass transfer of soot particles through the porous catalysts. The synergic effect of Pt-Pd binary components is favorable for enhancing the intrinsic redox property originated from the strong metal (PtPd)-support (TiO2) interaction (SMSI). Remarkably, PtPd/3DOM-TiO2 catalyst exhibits highest catalytic activity for diesel soot combustion in comparison with those of supported single Pt or Pd NPs, i.e., its values of T10, T50 and T90 are only 262, 338 and 386 °C, respectively. And the TOFPtPd value of PtPd/3DOM-TiO2 catalyst (1.27 × 10−3 S−1) is 4.3 times as much as that of Pd/3DOM-TiO2 catalyst (0.29 × 10−3 S−1). In addition, PtPd/3DOM-TiO2 catalyst shows the good stability of activity and nanostructure during five cycles of soot-TPO tests. The ternary catalyst of 3DOM TiO2-supported uniform Pt-Pd alloy NPs can not only decrease the usage amount of Pt, but also is potential to practical application in catalytic combustion of diesel soot particles.