Polyol-pretreated SBA-16 supported Ni-Fe bimetallic catalyst applied in CO methanation at low temperature

Abstract

• Polyols were used to pretreat the mesoporous silica molecular sieve SBA-16 to adjust the surface groups. • Bimetallic Ni-Fe catalysts with polyol-pretreated support were obtained. • The mechanism of how the polyols influence the surface SiOH groups and thus the metal particles distribution was figured out. • Catalysts with polyol-pretreated support lowered the minimum temperature for CO complete conversion to 230 °C from 290 °C. Polyols were used to pretreat the mesoporous silica molecular sieve SBA-16 and thus supported bimetallic Ni-Fe catalyst was prepared in order to address the low activity of CO methanation at lower temperature. The characterization of the pretreated support and catalysts indicated that the residual polyols release heat during combustion, which could provide energy for the decomposition of metal precursors, lowering the decomposition temperature and reducing the metal particle size. More importantly, the pretreatment of support with polyols could increase the isolated silicon hydroxyl, and strengthen the metal-support interaction, thus obtaining smaller metal particles. The smaller metal particles promoted the dissociation of reactant gas, as a result, Ni-Fe bimetallic catalyst with polyol-pretreated support could lower the minimum temperature for CO complete conversion from 290 °C to 230 °C while keeping CH 4 selectivity above 90%. Catalysts with polyol-pretreated support provide a new possibility for low-temperature CO methanation technology.