Rational Surface and Interfacial Engineering of IrO2 /TiO2 Nanosheet Arrays toward High-Performance Chlorine Evolution Electrocatalysis and Practical Environmental Remediation.

The chlorine evolution reaction (CER) is a critical and commercially valuable electrochemical reaction in industrial-scale utilization, including the Chlor-alkali industry, seawater electrolysis, and saline wastewater treatment. Aiming at boosting CER electrocatalysis, hybrid IrO2 /TiO2 nanosheet arrays (NSAs) with rational surface and interfacial tuning strategies are proposed in this study. The IrO2 /TiO2 NSAs exhibit superb CER electrocatalytic activity with a low overpotential (44 mV) at 10 mA cm-2 , low Tafel slope of 40 mV dec-1 , high CER selectivity (95.8%), and long-term durability, outperforming most of the existing counterparts. The boosting mechanism is proposed that the aerophobic/hydrophilic surface engineering and interfacial electronic structure tuning of IrO2 /TiO2 are beneficial for the Cl- mass-transfer, Cl2 release, and Volmer-Heyvrosky kinetics during the CER. Practical saline wastewater treatment by using the IrO2 /TiO2 NSAs electrode is further conducted, demonstrating it has a higher p-nitrophenol degradation ratio (95.10% in 60 min) than that of other electrodes. The rational surface and interfacial engineering of IrO2 /TiO2 NSAs can open up a new way to design highly efficient electrocatalysts for industrial application and environmental remediation.