Solid State Ionics, Vol.145, No.1-4, 109-118, 2001
Proton-conducting sol-gel hybrids containing heteropoly acids
Organically modified silicate/heteropoly acid hybrids were made through a sol-gel process from ethoxy silane functionalised by polypropylene glycol of various chain lengths. Heteropoly acids were incorporated as a source of protons. The gels with a high heteropoly acid loading show protonic conductivities of about 10(-3) S/cm at room temperature. The process of crystallisation and agglomeration of Keggin units was followed by X-ray diffraction and infrared spectroscopy. The membranes were applied in a direct methanol fuel cell at room temperature.
Keywords:sol-gel;organic-inorganic hybrid materials;protonic conductivity;phosphotungstic acid;silicotungstic acid;fuel cells;membranes;IR spectroscopy