Synthesis and performance of solid proton conductor molybdovanadosilicic acid

Abstract

A molybdovanadosilicic acid H₅SiMo₁₁VO₄₀·8H₂O was synthesized and investigated in this work. The structure features and hydration degree of this acid were characterized by IR, UV, XRD and TG-DTA. Its proton conductivity was studied by electrochemical impedance spectroscopy (EIS). The EIS measurements demonstrated that H₅SiMo₁₁VO₄₀·8H₂O showed excellent proton conduction performance with proton conductivity reaching 5.70 × 10⁻³ S cm⁻¹ at 26 °C and 70% relative humidity. So, it is a new solid high proton conductor. The conductivity enhances with the increase of temperature, and it exhibits Arrhenius behavior. The activation energy value for proton conduction is 21.4 kJ mol⁻¹, suggesting that the proton transfer in this solid acid is dominated by Vehicle mechanism.