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Two electrodes for anodic water oxidation made by direct synthesis of inorganic catalysts onto conductive carbon fibre sheets are evaluated. As catalysts two Co- and Sb-containing phases were tested, that is, Co3Sb4O6F6 and the new compound CoSbO4. The compounds express large differences in their morphology: CoSbO4 grows as thin needles whereas Co3Sb4O6F6 grows as larger facetted crystals. Despite the smaller surface area the latter compound shows a better catalytic performance. When the compound Co3Sb4O6F6 was used it gave a low increase of +0.028 mV h−1 at an overpotential of η=472 mV after 10 h and a stability of +0.48 mV h−1 at an overpotential of η=488 mV after 60 h. The leakages of Co and Sb were negligible and only <0.001 at % Co and approximately 0.02 at % Sb were detected in the electrolyte. [ABSTRACT FROM AUTHOR]

Water Splitting Catalytic water splitting is a very active research field, and many organic and inorganic catalysts have been tested for the oxidation reaction that is more challenging to catalyse at a low overpotential than the reduction reaction. Metalorganic catalysts most often survive only for short time period, so inorganic compounds are in general more promising. Several promizing oxide compounds containing cobalt have previously been identified and studied. To investigate direct synthesis of catalytically active compounds and their long time behavior, H. Svengren et al. have synthesized crystals of Co3Sb4O6F6 and the new compound CoSbO4 directly onto carbon electrodes. In their Full Paper on page 568 ff., they show the importance of making long‐term stability tests when ranking the performance of different catalysts. [ABSTRACT FROM AUTHOR]