Facile One-step Preparation of Mesoporous Siliceous phophsomolybdic acid for Proton Exchange Membrane

Abstract

Proton exchange membrane is art of PEM fuel cells, developing active materials with robust structure and high proton conductivity has attained huge attention in recent decade amongst researchers. Here we have developed a novel approach to prepare a siliceous mesoporous heteropoly acid with high stability in polar media and high proton conductivity to be utilized as proton exchange membrane. A highly stable mesoporous siliceous phosphomolybdic acid has been synthesized via a simple self-assembly between phosphomolybdic acid (PMA), the polymeric surfactant, and the silica precursor stabilized by KCl molecules as a proton conducting material for proton exchange membrane application. As prepared siliceous mesoporous phosphomolybdic acids (mPMA-Si) show a high surface area with a highly crystalline structure, however the crystallinity reduced by increasing the silica content. Further analysis proved the Keggin structure remain intact in final materials. mPMA-8 Si shows the highest performance among all the materials studied with proton conductivity of 0.263 S.cm-1 at 70 oC. As prepared mPMA-xSi has shown a very high proton conductivity in a range of temperatures which make them a promising material for proton exchange membrane.