Metal-oxide interaction enhanced CO2 activation in methanation over ceria supported nickel nanocrystallites

The role of metal-support interaction in determining CO2 activation and conversion for methane production was examined over (CeO2, TiO2 and SiO2) supported Ni nanoparticles. Hexagonal Ni nanocrystallites on CeO2 with strong metal-oxide interaction selectively produced CH4 at (up to forty-fold) higher turnover frequencies (TOFs) than that recorded over (TiO2 and SiO2) supported Ni nanoparticles. A stronger adsorption of CO2 and H-2 was identified for Ni/CeO2 using temporal analysis of products (TAP). Decoration/encapsulation of Ni nanoparticles by a thin layer of reduced ceria can decrease the catalytic capacity for CO2 activation/conversion. An initial loss of activity in the long-term stability evaluation over Ni/CeO2 can be linked to a reconstruction of hexagonal Ni nanocrystallites to quasi-spherical particles.