SURFACE ELECTROCHEMISTRY OF UO_(2) IN DILUTE ACIDIC HYDROGEN PEROXIDE SOLUTIONS

摘要

It has been shown that in acidic solutions with pH <2.6, hydrogen peroxide reduction catalyzed by an adsorbed U~(V) containing layer is the dominant reaction pathway, while at higher pH values (pH > 2.6), reduction catalyzed on a UO_(2+x) surface lattice layer dominates. At pH 2.6 with high hydrogen peroxide concentrations, reduction on both surfaces is sustainable. However, if hydrogen peroxide concentration is decreased, reduction on an adsorbed layer becomes the dominant pathway. Lowering hydrogen peroxide concentration increases the buffer capacity of the solution and prevents pH localization at the electrode surface. The resultant destabilization of the UO_(2+x) surface lattice layer suppresses hydrogen peroxide reduction on such a surface layer.