Facile One-Step Preparation of Mesoporous Siliceous Phophsomolybdic Acid for Proton Exchange Membrane

Abstract

Background: Proton exchange membrane is an art of PEM fuel cells, developing active materials with robust structure and high proton conductivity has attained huge attention in recent decades amongst researchers. Aims/objectives: 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. Methods: 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. Results: As prepared, siliceous mesoporous phosphomolybdic acids (mPMA-Si) show a high surface area with a highly crystalline structure; however, the crystallinity is reduced by increasing the silica content. Further analysis proved the Keggin structure remains 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 °C. Conclusion: As prepared, mPMA-xSi has shown a very high proton conductivity in a range of temperatures, making them a promising material for proton exchange membrane.