Tuning the metal-support interaction via size-controlled ceria nanocubes in CO2 methanation over Ni/CeO2

Interaction between metal species and support affects the structural and electronic properties of metal species, thus changing the catalytic behaviour. This work demonstrates regulation of support size is an effective way to optimise the metal-support interaction over Ni/CeO 2 -cube. Smaller ceria cubes promoted formation of smaller Ni particle sizes with higher dispersion, generating stronger interaction between Ni and CeO 2 , and consequently higher turnover frequency for CO 2 methanation. The interaction in Ni/CeO 2 with the smallest ceria size (average ca. 5 nm) provides stronger CO 2 and H 2 adsorption capacity, facilitating the CO 2 methanation with over 99 % CH 4 selectivity at 548–573 K, delivering a CO 2 conversion rate of 327.9 mol CO2 mol Ni -1 h −1 , which is 1.9 and 14.0 times than that of the 12 nm and 20 nm counterparts at 573 K, respectively. In-situ FTIR spectroscopic analysis demonstrates the surface reaction proceeds via a formate pathway, and smaller CeO 2 -cube supported Ni facilitates conversion of carbonate/bicarbonate intermediates to formate species. The metal-support interaction aroused from controlled support size provides a new way to design high-performance methanation catalyst.