Nanoscale structural disorder in manganese oxide particles embedded in Nafion

Abstract

Earlier studies have shown that manganese oxide particles derived from a manganese molecular complex embedded in a Nafion film have one order of magnitude higher water-oxidation catalytic activity per manganese compared to many unsupported solid-state manganese oxide particles. Using transmission electron microscopy and electron scattering simulations, we have shown that the sodium-birnessite phase particles in Nafion exhibit an exceptionally high degree of layer mis-registration, and a high concentration of Mn vacancies, compared to the synthetic birnessite nanoparticles. It is therefore proposed that the differences in the activities correlate with the degree of disorder in the manganese oxide particles.