Proton conductivity of imidazole functionalized ordered mesoporous silica: Influence of type of anchorage, chain length and humidity

A detailed comparison of the proton conductivity of highly ordered high surface mesoporous silica material Si-MCM-41 functionalized with imidazole groups by different anchoring routes is presented. The samples were characterized by X-ray diffraction, nitrogen adsorption and FT-infrared spectroscopy. The proton conductivity is deduced from impedance spectra taken in the temperature range of 60–140 °C. All materials show strong dependence of the proton conductivities on the type of anchorage, the degree of functionalization, spacer chain length between silica host and functional imidazole group, and the relative humidity.