Controlling the distribution of cobalt (oxide) nanoparticles in the dual pore system of SBA-15 scaffolds

Different solvents (i.e., water, hexane-water mixture and ethanol) are used as dilution media for metal nitrate precursors. It was demonstrated that the interplay between the properties of the solvent and the particularities of the SBA-15 scaffold is the key to control: (i) the localization of NPs, (i.e., confined in the main mesopores and/or in the intrawall micro-/mesopores), and (ii) the metal precursor-silica interactions through the formation of phyllosilicate-like phase (PS) stabilizing oxide phase, which in turn, enables achieving different dispersion degrees of the NPs. It was shown that the samples containing cobalt-based NPs confined into the intrawall pores as well as PS-like phases exhibited higher thermal stability but lower reducibility. The catalytic results, obtained on the active metallic phase for the hydrogenation of cinnamaldehyde, emphasize the role of the metal dispersion on the activity and selectivity in reaction of the material. [Display omitted] •Water as solvent leads to large agglomerates of NPs into the primary mesopores.•Organic solvents favor the formation of dispersed NPs into the intrawall pores.•Formation of phyllosilicate-like phase (PS) stabilizing oxide phase.•Catalytic behavior of Co NPs in hydrogenation reaction depends on NPs dispersion.