Preparation and catalytic properties of low content Ag-added ZrO2 for soot oxidation

Abstract

Low content (0.13.4 wt %) Ag added ZrO2 catalysts were synthesized by a hydrothermal method for soot combustion catalysis. The thermal stability and microstructure were characterized by X-ray diffractogram, field emission scanning microscopy, surface area and X-ray Absorption Fine Structure (XAFS) measurement. Soot oxidation temperature of Ag/ZrO2 catalysts was able to be controlled by changing heat-treatment temperature for starting powders. The mixture of metallic Ag and ionic Ag2O was observed by the XAFS spectra, and catalysts maintaining thermal stability were modified by active Ag/Ag2O mixed state on ZrO2. The catalysts with only 0.9 and 3.4 wt % doping of Ag in ZrO2 were effective and a better candidate for diesel soot oxidation catalysis.