Preparation of mesoporous silica nanocapsules with a high specific surface area by hard and soft dual templating approach: Application to biomass valorization catalysis

Mesoporous silica nanocapsules were prepared by a soft and hard dual templating approach. Carbon black and carbon nanofibers, used as sacrificial templates (hard template) have been coated by a mesoporous silica layer. Pluronics (P123/F127) and cetrimonium bromide were selected as surfactants (soft template) to produce mesoporous layers with different morphologies and pore sizes. The coated samples were then calcined at high temperature to remove the hard template and produce silica nanocapsules with mesopores in their walls. The so-obtained materials have been characterized by XPS, elemental analyses (ICP), TEM, N2 physisorption and XRD. The results have shown that the obtained materials exhibit a high specific surface area and a short diffusional pathway within the porous structure, which represents a significant advantage for catalysis applications. Finally, mesoporous acidic nanocapsules were prepared by sulfonic acid moieties grafting, and were tested as a catalyst in a biomass valorization reaction, the hydrolysis of cellobiose. The catalysts have shown high catalytic performances underlining the high potential of the present synthetic approach to produce versatile mesoporous materials.