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Updated: Mar 18, 2026

Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts
Published on: August 7, 2018
Reactive oxygen species accelerate degradation of anion exchange membranes based on polyphenylene oxide in alkaline
Javier Parrondo1, Zhongyang Wang1, Min-Suk J Jung1
1Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, 10 W. 33rd St., Chicago, IL 60616, USA. ramani@iit.edu.
Abstract:
Anion exchange membranes (AEM) based on polyphenylene oxide (PPO) suffered quaternary-ammonium-cation-site degradation in alkaline environments. Surprisingly, the degradation rate was considerably faster in the presence of molecular oxygen. We postulated that the AEM cation-site catalyzes the reduction of dioxygen by hydroxide ions to yield the superoxide anion radical and the highly reactive hydroxyl free radical. We substantiated our hypothesis by using a phosphorous-containing spin trap (5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide) to detect the adducts for both free radicals in situ using (31)P-NMR spectroscopy.
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