2, Shell Technology Centre Amsterdam, Amsterdam, , Netherlands
Perovskites belong to a family of compounds with crystal structure as ABX3 in which A and B are cations and X is an anion. These perovskites find useful applications in the areas of fuel cells, hydrogen gas sensors and steam electrolysis. With a cage like structure perovskites are now being used in absorbing and transporting small ions and molecules like protons. Thus, their proton conduction at high temperatures is now being utilized in fabricating membranes for reactors for catalytic dehydrogenation/hydrogenation processes. In comparison to the already studied BaZrO3, SrZrO3 has lower proton conduction at varied temperature window.
In our study we have analysed the relative proton conduction between two perovskites, that is, BaZrO3 and SrZrO3. In these two materials individual dynamical and thermodynamical energy barriers for proton transfer from one oxygen atom to another were determined. Thermodynamics of proton conductivity in these systems were addressed by performing activation energy barrier calculations for proton hopping transition states using Nudged Elastic Bands (NEB) theory and ab-initio quantum chemical calculations. MD simulations were also performed to determine the activation energy from trajectories of SrZrO3. In the end correlations and comparisons were made between the energy barriers obtained from dynamical (MD) and thermodynamical (NEB) runs that were performed on SrZrO3. In order to study the electronic conductivity their band structures shall also be determined. Subsequently, similar operations are being performed for the sandwich of SrZrO3 and BaZrO3 as a model for electrode electrolyte assembly. We shall also report the interfacial properties of BaSrZrO3.