What's your application? There are many papers on cerium oxide in fuel cells as a radical scrubber, metal centres as the active sites anion-exchange membranes...
there are different papers related to metal oxides in membranes for gas separation.
just an example:
S.S. Madaeni, M. Moahamadi Sarab Badieh, V. Vatanpour, N. Ghaemi, Effect of Titanium Dioxide Nanoparticles on Polydimethylsiloxane/Polyethersulfone Composite Membranes for Gas Separation, Polymer Engineering and Science, 52 (2012).