Abstract
Abstract
The thermochemical water splitting IS process is one of the hydrogen production method to use a heat directly. The temperature of the thermal decomposition of water (4000 K) can be reduced under 700 K by introducing I2 and SO2 as recycling catalysts. One of the problems in the IS process is that the conversion of the HI decomposition reaction is low at about 20%. If a membrane reactor with the H2 permselective membrane is applied to the HI decomposition reaction, the hydrogen can be extracted to improve the HI conversion. We focus on a counter diffusion CVD method for the preparation method of the membranes. Two reactants (e.g. silica precursor and oxidant) are provided at the opposite side of the porous substrates and hybrid silica is deposited inside the pore of the substrate. The pore sizes are controlled by introducing organic functional groups to silica precursor. In this study, the silica hybrid membrane with high H2 permeation performance and high H2/HI selectivity were developed by introducing organic functional groups. Effects of the organic functional groups were summarized by using a pore model. The HI gas and other inorganic gases permeation performance were tested through silica hybrid membranes.