Harnessing LaCoO3 Perovskite as a Sustainable Catalyst for Electrochemical Chlorine Evolution in Dye-Contaminated Saline Wastewater

The chlorine-evolution reaction (CER) process is a cleaner and practical way for industrial-scale chlorine generation and seawater electrolysis. Recently, significant efforts are underway to design noble metal-free electrodes for chlorine production via an electrochemical process. In view of developing efficient, stable, and cost-effective electrodes for effective chlorine production, we designed a chemical method to stabilize lanthanum cobaltite, which possesses a perovskite structure. Detailed structural analysis shows that lanthanum cobaltite crystallizes in the rhombohedral structure. Morphological analysis of LaCoO3 using TEM indicates an average size of 50 nm. Further, the electrochemical chlorine evolution performance of nanosized LaCoO3 shows an overpotential of 100 mV at 10 mA/cm(2), Tafel slope of 50 mV dec(-1), with CER selectivity of 93.5%, while Faradaic efficiency was calculated to be 94.8%. The wettability contact angle studies reveal that lanthanum cobaltite has a highly hydrophilic surface, ensuring efficient mass transfer ability due to the non-adhesion of gas bubbles to the surface. Additionally, in situ generated chlorine achieved a 98% success rate in detoxifying model saline wastewater containing Procion Red MX-5b dye. Our study is aimed at developing a sustainable and promising electrode material that provides innovative insights in solving real-world problems by showcasing seawater model electrolysis for the application of chlorine production as well as detoxification of environmental pollutants.