Keywords: chemical vapour deposition, CVD, iodine–sulphur process, nuclear hydrogen production, silica membrane, sol-gel, thermochemical water-splitting, nuclear energy, nuclear power, hydrogen energy
The preparation characteristics of hydrogen permselective membranes for higher performance in nuclear hydrogen production
The thermochemical water-splitting method has been proposed as a clean method for hydrogen production. The IS (iodine–sulphur) process is one of the thermochemical water-splitting processes. The silica membrane to apply in membrane reactor for the HI decomposition reaction improvement of the IS process was prepared by sol-gel and thermal CVD (chemical vapour deposition) methods. In the prepared membrane by sol-gel method, the permeation mechanism of hydrogen and nitrogen gas is dominated with the activated diffusion and Knudsen diffusion, respectively. The activation energy of hydrogen was ca. 5 kJ/mol. In the prepared membrane by thermal CVD method, the deposited silica particle size was obtained less than 11 nm and the deposited thickness layer was about 2 µm. The selectivity of H2 to N2 was 26.3 at 450°C, and the permeance of H2 was 6 × 10-8 mol Pa-1 m-2 s-1.