Impact of the support on the catalytic activity of Ag nanoparticles for soot combustion

This study investigates the catalytic activity for soot combustion of Ag nanoparticles dispersed on various supports showing different redox properties. Temperature programmed soot oxidation and isotopic exchange experiments were performed to assess the impact of the soot/catalyst contact, the oxygen partial pressure and the ageing toward activity. Three different contact modes have been used to clearly highlight the catalytic performances: loose, tight and supertight. Whatever the support, in both loose and tight contact modes, the catalytic performances are linked with the Ag surface concentration which was found to be high on zirconia-based catalysts and low on ceria-zirconia. The ignition of the soot combustion process occurs on Ag nanoparticles except for catalysts supported on Yttria-Stabilized Zirconia (YSZ), a pure oxygen ionic conductor, where Ag nano particles only promote the run-away of the reaction at higher temperatures. Catalysts based on SiO2, ZrO2 and YSZ exhibit a remarkable hydrothermal stability as performances in tight contact mode are fairly similar after the hydrothermal ageing.

Automated summary

This study investigates the catalytic activity of Ag nanoparticles dispersed on various supports with different redox properties for soot combustion. The results show that the catalytic performance is related to the Ag surface concentration, and different contact modes have different impacts on catalytic performances. Moreover, the catalysts show remarkable hydrothermal stability after ageing.