Preparation of nickel (oxide) nanoparticles confined in the secondary pore network of mesoporous scaffolds using melt infiltration

•Melt infiltration is efficient for the dispersion of nickel in micro-mesoporous silica.•Properties of the secondary intra-wall porosity is decisive in dispersing Ni phase.•A high degree of interconnectivity between the two porosities is in favor of NPs formation in the intra-wall pores.•Excellent properties for cinnamaldehyde and 5-HMF hydrogenations are obtained over intra-wall pore confined NPs.