Pd掺杂量对有机无机杂化SiO₂膜H₂/CO₂分离性能和水热稳定性能的影响

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^-7 mol•m^-2•s^-1•Pa^-1 and 13.6, respectively. This result indicated that as-prepared POS membrane exhibited good H₂ permeance, H₂/CO₂ permselectivity and hydrothermal stability.