Synthesis and performance of solid proton conductor molybdovanadosilicic acid

Area of Science:

• Inorganic Chemistry
• Materials Science
• Electrochemistry

Background:

• Heteropolyacids (HPAs) are known for their potential applications in catalysis and proton conduction.
• Molybdovanadosilicic acid (H5SiMo11VO40·8H2O) is a specific type of HPA with unique structural and electronic properties.

Purpose of the Study:

• To synthesize and characterize a novel molybdovanadosilicic acid (H5SiMo11VO40·8H2O).
• To investigate the proton conductivity of this synthesized solid acid.
• To determine the mechanism of proton transfer within the material.

Main Methods:

• Synthesis of molybdovanadosilicic acid (H5SiMo11VO40·8H2O).
• Characterization using Infrared (IR) spectroscopy, Ultraviolet (UV) spectroscopy, X-ray Diffraction (XRD), and Thermogravimetric Differential Thermal Analysis (TG-DTA).
• Proton conductivity measurement via electrochemical impedance spectroscopy (EIS).

Main Results:

• The synthesized H5SiMo11VO40·8H2O was successfully characterized, confirming its structure and hydration degree.
• Electrochemical impedance spectroscopy revealed excellent proton conduction performance, with conductivity reaching 5.70 × 10^-3 S cm^-1 at 26 °C and 70% relative humidity.
• Proton conductivity increased with temperature, following Arrhenius behavior with an activation energy of 21.4 kJ mol^-1.

Conclusions:

• H5SiMo11VO40·8H2O is identified as a new solid high proton conductor.
• The proton transfer mechanism in this solid acid is predominantly governed by the Vehicle mechanism.
• The material exhibits promising properties for applications requiring efficient proton transport.