Mesoporous silica as a tunable support for dual-function Ba–Ru catalysts: impact on CO2 adsorption and methanation performance

The integration of CO2 capture and catalytic methanation into a single material platform presents an efficient route toward carbon-neutral fuel production. In this work, we investigate silica-supported dual-function materials (DFMs) comprising Ba as the CO2 storage component and Ru as the methanation catalyst. A series of Ba-Ru/SiO2 materials were synthesized via incipient wetness impregnation, with varying Ba loadings (16-32 wt%) and promoter deposition sequences. Structural, morphological, and surface analyses (BET, XRD, FT-IR) revealed the formation and thermal evolution of distinct carbonate species as a function of Ba content and preparation method. CO2-TPD and H2-TPSR experiments demonstrated that the impregnation order influences the nature, strength, and regenerability of the adsorbed carbonate species. Increasing Ba loading enhances CO2 uptake and promotes the formation of thermally stable bridging carbonates, while Ru positioning affects methanation activity and carbonate reactivity. Compared to alumina-based DFMs, silica-supported systems exhibit distinct carbonate populations and lower-temperature regeneration behavior due to the non-interacting nature of the support. These findings offer new insights into the design of mesoporous DFMs with tunable CO2 sorption and conversion performance, highlighting the properties of silica as support for integrated carbon capture and utilization.