Synthesis and Characterization of Ba_0.5Sr_0.5Ni_xCo_0.8‐xFe_0.2O_3‐δ (x=0 and 0.2) Perovskites as Electro‐catalysts for Methanol Oxidation in Alkaline Media

Abstract

In this study, the perovskite‐type oxides Ba0.5Sr0.5Ni0.2Co0.6Fe0.2O3‐δ (BSNCF) with different B‐site transition metal elements were investigated as a new catalyst for methanol oxidation. They were prepared by the partial substitution of cobalt by nickel in Ba0.5Sr0.5Co0.8Fe0.2O3‐δ (BSCF) sample. Both materials prepared using a combined citrate/EDTA complexing method and their catalytic activitiesfor methanol oxidation were comparativelystudied using cyclic‐voltammetry (CV) and chronoamperometry (CA) in alkaline media at room temperature. Structural, textural, morphological and redox properties of the synthesized solids were investigated by several physicochemical methods such as XRD, FTIR, LRS, SEM‐EDX, BET and H2‐TPR. The as‐prepared materials were obtained with high purity and high crystallinity. The partial substitution of cobalt by nickel in BSCF perovskite changes the structure of the solid which pass from cubic structure to a mixture of cubic and hexagonal forms. This change is accompanied by an increase in BET surface area and a decrease in crystalline size. For the electro‐catalysis measurements, results demonstrated that partially substituting of Co by Ni in BSCF structure enhance the electro‐catalytical activity towards the oxidation of methanol under alkaline conditions, making it an electro‐catalyst candidate for practical utilization in DMFCs.