Transition metal-doped rare earth vanadates: a regenerable catalytic material for SOFC anodes

Abstract

The physical and electrochemical properties of cerium vandates in which a portion of the cerium cations have been substituted with transition metals (Ce_1−xTM_xVO_4−0.5x, TM = Ni, Co, Cu) were investigated and their suitability for use in solid oxide fuel cell (SOFC) anodes was assessed. Similar to other transition metal doped perovskites, the metals were found to move out of and into the oxide lattice in response to exposure to reducing and oxidizing conditions at elevated temperatures. This process produces nanoparticle metal catalysts that decorate the surface of the conductive cerium vanadate. Solid oxide fuel cells (SOFC) with Ce_1−xTM_xVO₃–YSZ composite anodes exhibited high electrochemical activity. It was also demonstrated that doping with the alkaline earth ions, Ca²⁺ and Sr²⁺ enhances the electronic conductivity of the vanadate and Ce_0.7Sr_0.1Ni_0.2VO₃–YSZ composite SOFC anodes were found to have both high electrochemical activity and unusually high redox stability.