Abstract
Surface reactivity and near-surface electronic properties of SrO-terminated SrTiO3 and iron doped SrTiO3 were studied with first principle methods. We have investigated the density of states (DOS) of bulk SrTiO3 and compared it to DOS of iron-doped SrTiO3 with different oxidation states of iron corresponding to varying oxygen vacancy content within the bulk material. The obtained bulk DOS was compared to near-surface DOS, i.e. surface states, for both SrO-terminated surface of SrTiO3 and iron-doped SrTiO3. Electron density plots and electron density distribution through the entire slab models were investigated in order to understand the origin of surface electrons that can participate in oxygen reduction reaction. Furthermore, we have compared oxygen reduction reactions at elevated temperatures for SrO surfaces with and without oxygen vacancies. Our calculations demonstrate that the conduction band, which is formed mainly by the d-states of Ti, and Fe-induced states within the band gap of SrTiO3, are accessible only on TiO2 terminated SrTiO3 surface while the SrO-terminated surface introduces a tunneling barrier for the electrons populating the conductance band. First principle molecular dynamics demonstrated that at elevated temperatures the surface oxygen vacancies are essential for the oxygen reduction reaction.
Highlights
Complex oxide, ceramic materials have attracted significant academic and industrial attention recently with their application in the fields of electronics [1], catalysis, photochemistry [2,3], water electrolysis [4], and solid oxide fuel cells (SOFC)
We investigate the density of states (DOS) and electron density distribution in bulk SrTiO3 and SrTiO3 surfaces, as well as, high temperature oxygen reduction reaction
We should clearly note that SrTiO3 and iron doped SrTiO3 differ from the actual operating materials in SOFC such as LaxSr1-xCoyFe1-yO3-δ
Summary
Ceramic materials have attracted significant academic and industrial attention recently with their application in the fields of electronics [1], catalysis, photochemistry [2,3], water electrolysis [4], and solid oxide fuel cells (SOFC). Amongst the various crystal lattices of complex oxides, the perovskites play significant role in modern energy relegated materials’ research. They find application in processes like artificial photosynthesis, steam electrolysis, and most importantly, as SOFC electrodes and electrolytes. The perovskite oxide lattice has the general formula ABO3 and it is composed by two different metal ions occupying lattice sites denoted as A-site and B-site. The B-site ions are usually small transition metals characterized with large formal charge, positioned in an octahedral site, coordinated by six oxide ions. Those octahedra are constructing the BO2-sublattice of the perovskites. The A-site ions are usually large alkali and alkaline earth metals occupying the cavities formed by the BO2-sublattice and
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
