Biochar as support in catalytic CO2 methanation: Enhancing effect of CeO2 addition

Abstract

Activated biochar obtained through slow pyrolysis and subsequent activation with CO2 was chosen as support in the synthesis of low Ni-content catalysts to be employed in CO2 methanation process. The main aim of this work was to obtain a more sustainable catalytic formulation compared to those proposed in literature. Biochar-supported catalyst resulted to be efficient in CO2 methanation, but with a relatively low selectivity toward methane. Support doping with CeO2 led to a remarkable increase in methane yield and in stability overtime. A maximum CH4 production was achieved with a CeO2 loading of 30 wt.%. Nevertheless, the lowest deactivation rate was observed for a support loaded with 50 wt.% of CeO2 Ceria promotes a faster activation of the CO2 molecule and a strengthens the Ni/support interactions, resulting in reduced active phase mobility and moderate sintering phenomena. The outcomes of this work were attractive for further studies related to the improvements in the catalyst stability.