Silver and manganese oxide catalysts supported on mesoporous ZrO2 nanofiber mats for catalytic removal of benzene and diesel soot

Abstract

Mesoporous zirconia (ZrO2) nanofibers were synthesized by an electrospinning method and calcination at 600°C. Ag and Mn oxides were separately or simultaneously deposited on the ZrO2 nanofibers by impregnation methods. The structure of the ZrO2 supported nanofiber materials were examined by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Ag and Mn oxides were homogeneously deposited on the surface of ZrO2 nanofibers. Metallic Ag species and Mn2O3 were formed on the ZrO2 nanofibers when they were separately deposited, whereas the codeposition of Ag and Mn changed the oxidation state of Mn oxides on the catalyst surface. The supported catalysts were evaluated for their soot and benzene oxidation performance. The co-deposition of Ag and Mn lowered the light-off temperature for benzene oxidation. The soot oxidation performance was comparable for the Ag/ZrO2, Mn/ZrO2 and Ag-Mn/ZrO2 catalysts under tight contact mode, whereas Ag/ZrO2 exhibited the highest activity and the activity decreased with decreasing the Ag content under loose contact mode.