Electronic and Catalytic Behavior of Mn-based Spinels Grown by Molecular Beam Epitaxy

Previous research on manganese-based spinel structures has shown that some exhibit strong oxygen reduction reaction catalytic behavior for water splitting in hydrogen fuel cells. However, there have been limited efforts to study these materials as epitaxial thin films which can be used for surface catalysis studies. With this in mind, thin films of spinel structures such as MnFe₂O₄, CoMn₂O₄, NiMn₂O₄ and Mn₃O₄ were synthesized to study the relationship of electronic properties and catalytic behavior. Films were grown using a molecular beam epitaxy system which allowed for precise control of sample stoichiometry. After growth, films were transferred to an in-situ x-ray photoelectron spectroscopy system to be examined without exposure to atmosphere. In addition, measurements characterizing the films’ electronic and catalytic properties such as ellipsometry and cyclic voltammetry were also performed. The combination of these studies allows for a greater understanding of these spinels and how they might be used in future catalytic applications.