Silica membranes for hydrogen separation prepared by chemical vapor deposition (CVD)

The preparation of silica membranes by chemical vapor deposition (CVD) is critically reviewed, with focus placed on the two most common supports used, Vycor glass and porous alumina. The major application of the membranes is hydrogen separation, but other gases can also be separated by functionalization of the silica. A description is given of the different gas transport mechanisms, and a comparison is provided to palladium membranes.