Flame spray pyrolysis (FSP) was employed to synthesize Ti-modified SiO₂ in a single step, serving as the support for Ru-based catalysts in CO₂ methanation reactions. The addition of Ti led to the formation of anatase and rutile TiO₂ phases, enhancing the catalytic activity of Ru/Ti-SiO₂ catalysts. Benchmarking between Ru/Ti-SiO₂ catalysts of various Ti concentrations prepared using one-step FSP techniques indicated significantly higher catalytic activity for the impregnation-made catalysts compared to the FSP-made ones, where diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) revealed different CH₄ formation mechanisms between two techniques. For FSP-made catalysts, it predominantly occurred through the CO route, whereas the impregnation-made proceed via both the dissociative adsorption of CO₂ (CO route) and through surface formate species formation. To explain the effect of Ti loading on Ru/SiO₂ catalysts, a multiscale analysis combining density functional theory (DFT) and microkinetic modeling was performed to study the adsorption behavior of CO₂ on different catalysts. The results revealed that a high amount of Ti reduced the adsorption strength of CO₂ on Ru/SiO₂ catalysts, indicating a modified interaction between CO₂ and the catalyst surface.
Mekasuwandumrong, O., Saelee, T., Noppakhun, J., Rittiruam, M., Khajondetchairit, P., Debecker, D., Praserthdam, S., & Praserthdam, P. (2025). A combined DFT-Experimental study on FSP-made Ru/Ti-SiO2 catalysts for CO2 methanation. Molecular Catalysis, 582, 115179. https://doi.org/10.1016/j.mcat.2025.115179 (Original work published 2025)