Charge particle dynamics and electrochemical behaviour of SrTiO3-δ as anode material for IT-SOFC applications

Abstract

SrTiO3-δ is a well-known metal oxide with cubic perovskite structure. In this work, we have synthesized SrTiO3-δ via conventional solid-state reaction route (SSR) and studied its electrochemical behaviour in three different pH media viz. 1 M aqueous solution of Na2SO4, (pH 7, neutral medium), KOH (pH 14, basic medium) and 0.5 M solution of H2SO4 (pH 1, acidic medium). The cubic phase with lattice constant, a = 3.905 Å is confirmed through XRD measurements. The electrical characterization of the sample was done in the frequency range 1Hz to 1 MHz and temperature range 25 oC–700 oC. The dynamics of the charged particles in the sample was studied using Jonscher power law. The scaling behaviour of the system has been investigated to understand the conduction mechanism. Further, charge carrier kinetics was also studied to understand the ionic contribution. Electrocatalysis was studied by cyclic voltammetry confirming the redox process in neutral and basic media, which was further confirmed in the XPS study. A better redox coupling occurs that was related to the Ti d-orbital and the O p-orbital interaction. The conductivity and catalytic properties of these materials indicated their use in different applications such as in fuel cells, sensors as well as in electrochemical devices.