Pd Doping on H2/CO2 Separation Performance and Hydrothermal Stability of Organic-inorganic Hybrid SiO2 Membranes

Pd-doped organic-inorganic hybrid SiO2 (POS) sols were synthesized by using 1,2-bis(triethoxysilyl) ethane (BTESE) and palladium chloride as precursors. POS membranes were fabricated via dip-coating process followed by calcination in the water vapor environment. The microstructure of POS powders was characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), N2 adsorption-desorption and transmission electron microscope (TEM). Effect of the molar ratio of Pd to Si (n (Pd/Si)=0.1, 0.5 and 1) on separation performance and hydrothermal stability of POS membranes was investigated. Results showed that with the increase of Pd doping amount, H2 permeance of POS membranes increased while the permselectivity of H2/CO2 decreased. After exposing to 100 kPa steam atmosphere for 180 h, H2 permeance and H2/CO2 permselectivity of the POS membrane prepared with n (Pd/Si) of 1 reached 1.62×10 mol·m·s·Pa and 13.6, respectively. This result indicated that as-prepared POS membrane exhibited good H2 permeance, H2/CO2 permselectivity and hydrothermal stability.