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摘要
Noble metal hydrous oxides are known to be recalcitrant systems, i.e. they either undergo reduction at high overpotential or fail to undergo this reaction, due to the intervention of high-energy, virtually isolated atom or nanocluster states of the element as primary reduction products. Hydrogen absorption by activated palladium in base results in enhanced levels of surface activation and eventually to the spontaneous generation of recalcitrant hydrous oxide species which deactivate the electrode surface. Hydrous oxide behaviour at palladium in base is significantly more complicated than in acid; the deposits in question are less readily formed in base, and the main component of a multilayer oxide film grown in acid (HO2) seems to alter to a more readily reducible form (HO1) on transferring the electrode to base. However, evidence was obtained serendipitously in the present work for the formation of a recalcitrant oxide deposit on palladium in base; the involvement of metastable metal and hydrous oxide states provides the basis of energy storage and anomalous heat emission behaviour which is a controversial topic in the case of this electrode system.
- 出版日期2010-8
