Active, selective and stable NiO-CeO2 nanoparticles for CO2 methanation.

CO 2 hydrogenation to CH 4 (or methanation) has been proposed to diminish CO 2 emissions producing a valuable fuel. A catalyst consisting of NiO-CeO 2 mixed oxide 6–7 nm nanoparticles with enhanced properties has been prepared, and compared with other NiO-CeO 2 reference catalysts including a mixed oxide with the same composition but without control of the size, a counterpart NiO-CeO 2 mixed oxide with three dimensionally ordered macroporous (3DOM) structure and an inverse catalyst consisting of bulk NiO-supported CeO 2 nanoparticles among others. At 275 °C the CO 2 methanation rate is near 3 times higher to that achieved with the counterpart reference catalyst prepared without control of the size, being more active than all reference catalysts. The selectivity towards CH 4 formation is ~100% in the whole range of temperature studied (until 500 °C), and kept the same activity and selectivity during a 25 h long-term test. The high activity of this catalyst is related with its high specific surface area (122 m2/g) and with the presence of highly-reducible Ni-O-Ce species on the nanoparticles surface • 6-7 nm NiO-CeO2 with enhanced activity for CO2 methanation has been prepared. • Reaction rate is 3 times higher to that of a catalyst prepared without size control. • Nanoparticles selectivity towards CH4 is near 100 % until 500 °C. • Nanoparticles kept the same activity and selectivity for 25 hours. [ABSTRACT FROM AUTHOR]