Redox Stability of phases based on bismuth oxide studied by voltammetry on microsamples
Résumé
Cyclic Voltammetry on microsamples was applied on bismuth tungsten oxides and bismuth molybdenum oxides to check their stability in reduction and define their limit of use. In this study, different mechanisms of reduction of bismuth were observed. Aurivillius Bi2WO derivatives exhibit a two steps mechanism (Bi0 Bi2+ and Bi2+ Bi3+), similar to pure bismuth oxide. In contrast the investigated bismuth molybdenum oxides (Bi26Mo10O69 related phases and Bi2Mo3O12) revealed a one step mechanism (Bi0- Bi3+). A better stability was therefore revealed for Bismuth-molybdenum oxides which are well known for their catalytic properties. This makes these materials attractive for use as membrane for catalytic dense membrane reactor.