Pore structure evolution of highly ordered mesoporous silica CMI-1 during boiling water treatment: a multi-technique investigation

The structural, textural and morphological evolution of calcined surfactant-free mesoporous molecular sieves treated in boiling water was investigated and explained by a three-step mechanism. The materials, prepared by a non-ionic surfactant [C16(EO)10] templating pathway, undergo a sharp decrease in surface area and pore size at the initial stage due to the partial hydrolysis of the silica walls. Then, the dissolution of the resulting branched (SiO)n chains attached to the internal surface of the pores results in a gain of surface area and pore size. Finally, the loss in surface area and the sharp increase in pore sizes is due to the destruction of the pore walls and thus of the materials.