Kateřina Minhová Macounová, Rebecca Katharina Pittkowski, Roman Nebel, Andrea Zitolo, Petr Krtil
The electrocatalytic behaviour of single-phase Ru1-xTixO2 materials was studied to outline general trends controlling the selectivity of oxide-based anodes in parallel oxygen evolution and chlorine evolution reactions. Materials with x ranging between 0 and 0.2 were prepared by spray freeze freeze drying approach. Prepared materials show a non-homogeneous distribution of Ti in the structure with dominant clustering of the Ti along the (001) direction. For materials with x higher than 0.1 the dominant linear clustering of Ti along the z-axis changes, including Ti clustering also along (111) direction. Prepared materials are active in both oxygen evolution and chlorine evolution reactions. The Ti has a pronounced effect on the selectivity of the prepared materials. Ti presence affects the selectivity of the prepared materials in a complex manner. Materials featuring a low Ti content (x∼0.05) retain a preference for oxygen evolution reaction even in presence of chlorides and are more selective for oxygen evolution than pure RuO2. The selectivity towards chlorine evolution increases with increasing Ti content and, apparently, also with clustering of Ti along the (111) direction. The selectivity towards chlorine evolution may be related to the tendency of the prepared catalysts to evolve the oxygen via lattice oxygen evolution reaction (LOER) reflecting the ability of the catalyst surface to form active sites under operando conditions.
Ru-Ti-O oxides, oxygen evolution, chlorine evolution, selectivity, local structure