Microstructural impact of anodic coatings on the electrochemical chlorine evolution reaction

Sol-gel Ru0.3Sn0.7O2 electrode coatings with crack-free and mud-crack surface morphology deposited onto a Ti-substrate are prepared for a comparative investigation of the microstructural effect on the electro- chemical activity for Cl2 production and the Cl2 bubble evolution behavior. For comparison, a state-of-the-art mud-crack commercial Ru0.3Ti0.7O2 coating is used. The compact coating is potentially durable on a long term compared to the mud-crack coating due to the reduced penetration of electrolyte. Ti L-edge X-ray absorption spectroscopy confirms that a TiOx interlayer is formed between the mud-crack Ru0.3Sn0.7O2 coating and the underlying Ti-substrate due to the attack of the electrolyte. Meanwhile, the compact coating shows enhanced activity in comparison to the commercial coating, benefiting from the nano particle nanoporosityarchitecture.Thedependenceoftheoverallelectrodepolarizationbehaviouron the local activity and the bubble evolution behavior for the Ru0.3Sn0.7O2 coatings with different surface microstructure are evaluated by means of scanning electrochemical microscopy and microscopic bubbl