Mesoporous silica nanosphere with open-mouth stellate pore architecture as a promising carrier for highly active solid acid catalysts

The mesoporous silica nanosphere containing the open-mouth stellate pore architecture (SMSN) was firstly prepared through a facile and practical hydrothermal approach in which urea acts as a cheap depositing agent to replace poisonous and high-cost organic amines. Using SMSN as a catalyst support, the supported phosphotungstic acid (PTA) catalyst was obtained by adopting an impregnation method. The as-prepared solid acid catalyst demonstrates much superior catalytic activity for diverse reactions to the supported catalyst on a worm-like mesoporous silica nanosphere (WMSN) as a support, originating from the promoted transfer of reactants and products, unique acidic properties and also the higher surface area of the supported PTA catalyst although SMSN has a lower surface area than WMSN, which results from its unique opening-mouth pore structure of SMSN. This work also presents an efficient approach to prepare highly efficient solid acid catalysts for many catalytic reaction processes by modulating the pore architecture of supports, besides tuning the morphology of carrier. The as-formed mesoporous silica nanosphere with opening-mouth stellate pore architectures using as an excellent carrier could be extended to the other supported-type catalysts for diverse reactions. Moreover, besides heterogeneous catalysis, the developed mesoporous silica nanospheres with unique pore architectures by the scalable method have a great potential to use in cell imaging, disease diagnosis, drug delivery, separation, and the other applications.