Increased methanation activity through passivation of the silica support

• RuNPs supported on standard and passivated SiO2 were prepared.
• Passivation of the silica surface enhanced the rate of methanation on RuNPs.
• CO inhibits methanation reaction.
• Passivation decreases the adsorption of CO (affinity) on RuNP.
• Change of rate is related to different CO affinity on supported RuNPs.

Improvement of the catalytic performance of supported nanoparticles (NP) is an intense area or research, which involves modification of many different parameters on a nanoparticle (such as variation of particle size), support (e.g. its reducibility) and metal–support interactions. Here, we focus on the latter and show that the introduction of passivating groups (–OSi(Me)2R with R = Me or Bu) at the interface between the support surface (silica) and RuNPs increases the rate of the reaction on RuNPs (per mole of surface Ru atoms) by a factor 5–6 compared to silica-supported RuNPs, whose surface is exposed to silanols. Chemisorption, IR spectroscopy and temperature-programmed desorption tests suggest that the rate increase likely originates from the difference in interaction between CO and RuNPs, which is influenced by the modification of the support surface functionality. It is also possible that the change in catalyst activity could be due to a modified electronic state of nanoparticles and/or their morphology.

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