Regular structures of SiO2 microneedles and Si micromonoliths have been formed using processing methods similar to those used in the microelectronics field; then these structures have been used as supports for zeolite (silicalite) films, grown on them by means of seeded hydrothermal synthesis. The procedure leads to microstructured nanoporous coatings with external characteristic dimensions of a few microns in size and short diffusion lengths, allowing intimate fluid–solid contact. Depending on the preparation conditions, the resulting films exhibit values of the external surface to volume ratio in the 400,000–700,000 m2/m3 range.

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