Colloid-imprinted carbons as templates for the nanocasting synthesis of mesoporous ZSM-5 zeolite

Colloid-imprinted carbons (CIC) with average pore sizes of 12, 22, 45, and 85 nm have been used as templates for the nanocasting of ZSM-5 zeolite with spherical domain sizes comparable to the pore sizes of the CIC template. The size and shape fidelity of the CIC-nanocasted zeolite allows one to control both the external surface area (16-127 m(2)/g) and the interparticle mesopore volume (0.05-1.19 cm(3)/g) through a rational choice of the template pore size. This flexibility in tailoring the particle textural properties makes it possible to optimize the catalytic properties of the zeolite for the conversion of molecules that are too large to penetrate the framework micropores and constrained to reacting only at active sites on the external particle surfaces. Conversely, for small molecule conversions within the framework micropores, the nanocasting method allows uniform tailoring of the diffusion path length to optimize reactivity or selectivity.