Engineering Delocalized Polarizations in Metal Oxide Electrodes with Conducting Polymers for Efficient and Durable Water-Splitting.

Oxygen evolution reaction is a pivotal anodic reaction for electrolysis, however, it remains the obstacle from its sluggish reaction kinetics originating from multiple electron transfer pathways at electrochemical interfaces. Especially, it remains a challenge to achieve stable operation at elevated current densities as electrodes suffer oxidative environment in corrosive conditions. Herein, we report that the conducting polymer polypyrrole electrodeposited Pr0.7Sr0.3CoO3 perovskite oxides for durable oxygen evolution electrodes. We found that the conducting polymer electrodeposited oxides exhibited a highly durable electrochemical oxygen evolution performance maintaining >99% of initial activities during the accelerated durability test. Meanwhile, bare metal oxides presented significant performance drops (<6% of initial activities) over the consecutive 20,000 accelerated durability test. High-resolution transmission electron microscope images identified the maintenance of high crystallinity of the heterostructure, suggesting that the electrodeposited pPy clusters can effectively delocalize highly polarized electrodes preventing material corrosion. The overall water electrolysis experiments further demonstrated that the heterostructure showed excellent stability at the high current density of 100 mA cm-2 over 700 hours. This marks the first report of the delocalized polarization benefiting from conducting polymers for durable oxygen evolution for perovskite oxides, suggesting great potential for scalable water electrolysis.