A quaternary ammonium grafted poly vinyl benzyl chloride membrane for alkaline anion exchange membrane water electrolysers with no-noble-metal catalysts

This work reported an alkaline anion exchange membrane water electrolyser (AAEMWE) without noble metal as the catalyst. Methylated melamine grafted poly vinyl benzyl chloride (mm-qPVBz/Cl−) was synthesized and cast as the membrane. The conductivity of this hydroxide ion exchange membrane increased from 1.6 × 10−2 S cm−1 to 2.7 × 10−2 S cm−1 when the temperature was increased from 25 °C to 60 °C. Membranes were examined using TEM. The oxygen evolution catalyst used was based on Cu0.7Co2.3O4 particle 20–30 nm in size, synthesized through a thermal decomposition method. A membrane electrode assembly was prepared with the resultant membrane as electrolyte, the Cu0.7Co2.3O4 nano-particles as the anode catalyst and Ni nano-powders as the hydrogen evolution catalyst. SEM observations showed that the catalysts were well dispersed on the electrodes. The polarization curves exhibited onset voltages for water electrolysis of around 1.5 V. The MEA polarisation in deionised water exhibited voltages of 2.19 V, 2.05 V, 1.99 V at a current density of 100 mA cm−2 at temperatures of 25 °C, 40 °C and 55 °C respectively.