 The silicate wall of the pores is amorphous.Mesoporous silicates, such as MCM-41 and SBA-15 (the most common mesoporous silicates), are porous silicates with huge surface areas (normally ≥1000 m²/g), large pore sizes (2 nm ≤ size ≤ 20 nm) and ordered arrays of cylindrical mesopores with very regular pore morphology.The large surface areas of these solids increase the probability that a reactant molecule in solution will come into contact with the catalyst surface and react.