Templating mesoporous hierarchies in silica thin films using the thermal degradation of cellulose nitrate

Materials containing a hierarchical pore structure (i.e. large pores leading to small pores) are highly desirable because they combine the advantages of high surface area with the rapid mass transport. Mesoporous SiO2 with hierarchical pore structure was prepared by a novel dual templating approach using a combination of cellulose nitrate and surfactants as the templates. Both ionic and non-ionic surfactants, or mixtures of surfactants, in conjunction with cellulose nitrate were used as the pore templates. Low angle XRD patterns show well-defined pore structures and BET shows surface areas from 500 to over 800 m2/g, with tunable bimodal or trimodal pore-size distributions from 18 Å to 0.3 μm. The hierarchical pore structure can be controlled by manipulating the template composition.