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The conversion of CO2 into CO via the Reverse Water–Gas Shift (RWGS) reaction is a suitable route for CO2 valorisation. Fe-based catalysts are highly active for this reaction, but their activity and selectivity can be substantially boosted by adding Cs as a promoter. In this work we demonstrate that Cs modifies the redox behaviour and the surface chemistry of the iron-based materials. The metallic dispersion and the amount of metallic Fe centres available for the reaction depends on Cs loading. 5 wt. % of Cs is an optimum amount of dopant to achieve a fair activity/selective balance. Nevertheless, depending on the RWGS reactor operational temperature, lower concentrations of Cs also lead to acceptable catalytic performance. Along with the excellent activity of the prepared materials this work showcases their robustness for long-term runs and the strong impact of H2/CO ratio in the overall catalytic performance.

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Mesoporous silica is a versatile material for use in catalysis and adsorption in energy, environmental, and medical applications. Here, for the first time, we report a flame aerosol synthesis method for a class of mesoporous silica materials with hollow, amorphous structure, low density, and specific surface area exceeding 1000 m 2 /g. We show its superior performance vs. MCM-41 in properties relevant to water purification, drug carrier, and thermal insulation applications. Moreover, we produced several types of mesoporous silica-supported nano-catalysts by in situ incorporation of active metals. The generality of this method is demonstrated by decorating mesoporous supports with noble metal, transition metal, and metal oxide nanoclusters, including Pt/SiO 2 , Ni/SiO 2 , CrO 3 /SiO 2 , and Co/Al 2 O 3 . As a prototypical application, we demonstrate dry reforming of methane using Ni/SiO 2 , achieving constant 97% CH 4 and CO 2 conversions for more than 200 hours, dramatically outperforming a corresponding MCM-41 supported Ni catalyst. Thus, this work provides a continuous and scalable strategy to produce mesoporous silica nanoshells, and the proposed in situ functionalization mechanism may pave the way to flexible catalysts for a diverse range of reactions.

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