SrCoO3-δ and SrCo1-xTixO3-δ perovskites as electrocatalytic materials for oxygen evolution reaction in alkaline environment

Here, we report the deposition of SrCoO 3-δ perovskites thin films by chemical bath deposition, employed as electrocatalytic layers for oxygen evolution reaction (OER) in alkaline water splitting. The effect of Co excess and Ti-doping on the crystalline structure, composition and electrochemical performances was investigated. The former had effect only on electrochemical performance whilst Ti-doping, above 3%, induced the formation of a secondary phase. Among all the investigated samples, SrCoO 3-δ :Co 3 O 4 (SCO:CB) sample showed the best electrochemical performance toward OER in 1 M KOH aqueous solution, reporting an onset overpotential, η onset , of 284 mV and a Tafel slope of 59 mV dec -1 . In contrast, Ti-doping (i.e. 3 %, SCT:CB 3 sample) drastically improved stability of the electrocatalytic layer, enabling 24 h of continuous operation, demonstrating the effectiveness of doping strategy to enhance SrCoO 3-δ perovskites durability. XPS analyses revealed that degradation of electrochemical performance of thin films is related to Sr leaching, even if Ti-doping decreased leached Sr amount improving layers stability. • SrCoO 3-δ thin films deposited by chemical bath deposition • Co excess improves OER activity, Ti doping enhances durability • Best sample shows η onset = 284 mV and Tafel slope = 59 mV dec −1 • Ti reduces Sr leaching, stabilizing perovskite electrocatalysts