Electrochemical Properties of CeVO4 and FeVO4 at High Temperatures

Abstract

High temperature corrosion of steel is dramatically accelerated by ashes and scales containing compounds of iron, vanadium, oxygen and sulfur. High temperature electrochemical impedance spectroscopy (HT-EIS) and cyclic voltammetry (HT-CV) on ash samples from a heavy crude oil furnace, showed high conductivity of at least one of the several existing phases and also some redox activity, which could be related to redox processes of vanadium containing compounds. On the one hand, it is unfavorable for the corrosion stability of construction materials; on the other hand it might be an effective material for several applications, like high temperature fuel cells electrodes, intercalation materials in ion-batteries or as catalyst. FeVO4 was identified as one of the few potentially highly conductive phases in the ash. Pure FeVO4 was synthesized and investigated by HT-EIS and HT-CV on micro-samples. For comparison CeVO4 was included in this investigation.