open access

https://hdl.handle.net/2115/81988

Anhydrous Proton Conduction of Soy Protein

英語

Acidic amino acid

2021-01

ESG

International Journal of Electrochemical Science

16(5)

151046

Water-soluble soy protein contains a large amount of acidic amino acids, such as glutamic and aspartic acids. Since these acidic amino acids possess the -COOH group in their side chain, the water soluble soy protein acts as an acidic polymer. Therefore, we prepared a composite material by the mixing of acidic protonated soy protein (SPH) and a basic heterocyclic molecule, such as imidazole (Im). The SPH-Im composite materials showed a thermal stability at <= 130 degrees C by the acid-base interaction between the acidic -COOH group, related to the side chain of the acidic amino acids, and basic Im molecule. Additionally, the proton conductivity of the SPH-Im composite material increased with the mixing of the Im molecule and reached a maximum proton conductivity at R=0.2. This proton conductivity was 4.4. 10-4 S cm(-1) at 130 degrees C under flowing dry nitrogen. Furthermore, the Ea of the proton conduction in the SPH-Im composite material was 0.27 - 0.76 eV. These results suggested that the proton conductive mechanism in composite material was based on the anhydrous proton transfer from the -COOH group to the deprotonated -COO- group.

学術雑誌論文

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Creative Commons Attribution 4.0 International

1452-3981