Enhancing oxygen reduction reaction catalytic activity using a sub-stoichiometric CaTiO3−δ additive

Platinum scarcity and its high cost have led to the requirement of alternative materials catalysing the oxygen reduction reaction (ORR), which is the main rate-determining step occurring in electrochemical devices, including metal-air batteries and fuel cells. We report a study on a sub-stoichiometric calcium titanate (CaTiO3−δ, CTO) compound used as promoter for the ORR in order to reduce the Pt loading and improve its electrocatalytic activity. Composite catalysts based on Pt/C with different amounts of CTO were prepared and their activity was investigated by rotating disk electrode (RDE). The obtained results proved a higher catalytic activity for the composite electrode, with respect to pure Pt/C, in terms of electrochemically active surface area, oxygen reduction current density, onset potential and stability. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim