Highly Active Nano-Perovskite Catalysts for Oxygen Evolution Reaction: Insights into Activity and Stability in Alkaline and Quasi-Neutral pH Electrolytes

Monday, 2 October 2017: 11:40
Chesapeake 12 (Gaylord National Resort and Convention Center)
B. Kim (Paul Scherrer Institut)
The water splitting reaction requires effective electrocatalysts to facilitate efficient oxygen evolution reaction (OER), which suffers from a high overpotential. Among cost viable electrocatalysts, PrBaCo2O5+δ and Ba0.5Sr0.5Co0.8Fe0.2O2+δ are gaining attention for their high specific activities toward OER in alkaline water electrolysis. Here, nanoparticles of PrBaCo2O5+δ and Ba0.5Sr0.5Co0.8Fe0.2O2+δ were prepared using a scalable flame spray synthesis rendering significantly high mass activities, current densities improve by 10 and 50 times, respectively, than compared to those prepared via the state-of-the-art synthesis method. Furthermore, up to date, only their performances under alkaline conditions (pH 13 – 14) have been exclusively studied barring lower pH values. We highlight that the assessment of activity and stability of perovskite catalysts in a quasi-neutral pH value is absolutely necessary for an extension of application in co-electrolysis of water and carbon dioxide in generation of hydrocarbon fuels. Therefore, we investigate their electrocatalytic performances in a quasi-neutral electrolyte where PrBaCo2O5+δ reveals more than three-folds higher mass activity than Ba0.5Sr0.5Co0.8Fe0.2O2+δ. To the best of our knowledge, for the first time, we narrate the dependency of electrocatalytic behaviors on the electrolyte pH with respect to their thermodynamic stabilities obtained from DFT based Pourbaix diagrams.