Mixed metal oxide catalysts for selective oxidation reactions and energy storage applications
Malte Behrens, University of Duisburg-Essen, Essen, Germany
Catalysts are materials that accelerate chemical reactions and make them more efficient and the related processes more sustainable. Reactions with oxygen play an important role in the functionalization of hydrocarbons to value-added products and in the context of energy storage and conversion. In the latter field, the oxygen evolution and the oxygen reduction reactions are kinetic bottlenecks for water electrolysis and fuel cells, respectively. These reactions can be catalyzed by mixed transition metal oxides, where the fist-row transition metals are of particular interest due to their high abundance and low cost. Studying these complex materials and their reactivity at the solid-liquid interface is challenging. Starting in 2018, a Collaborative Research Centre at the universities Duisburg-Essen and Bochum tackles this challenge for mixed iron-cobalt oxides. Its research programme is built on the systematic comparison of the same catalyst in a selection of different oxidation reactions in thermal, electro-, and photocatalysis. Emphasis is placed on the role of synthesis, which was found to affect the catalytic properties of cobalt ferrite spinel and lanthanum cobalt iron perovskite. First results show that the effect of synthesis parameters and method determined the microstructural properties of cobalt ferrite allowing to tune its selectivity in alcohol oxidation. The effect of composition was studied by substitution with Ni or V, which leads to an improvement of the electrochemical OER avtivity.