A review on research progress of double perovskite oxides for oxygen evolution reaction electrocatalysts and supercapacitors†

Abstract

In the past decade, the rapidly increasing global demand for energy and extensive concerns about the greenhouse effect and environmental problems from fossil fuels have stimulated intensive research interest in developing sustainable and clean energies and new electrochemical energy storage systems. Practical utilization of clean energies requires energy conversion involving different processes such as electricity-driven water splitting facilitating the storage of electrical energy in the form of hydrogen gas, and energy storage devices such as fuel cells and supercapacitors. A key issue to realize a high-efficiency conversion process is to find stable, low-cost and environment-friendly functional materials. Due to their extreme structural and compositional flexibilities, double perovskite (DP) oxides have gained much attention in the fields of electrocatalysis and supercapacitors. Recently, high-level theoretical studies have led to significant progress in the atomic-scale understanding of the catalytic mechanism of the DP oxide-driven oxygen evolution reaction (OER) and the electrochemical energy storage mechanism in DP oxide-based supercapacitors. In parallel, numerous experimental studies have been carried out to explore novel catalytic materials with advanced properties and kinetics, and more promising pseudocapacitive DP oxides have been developed. This review first introduces the structural and compositional flexibilities of DP perovskite oxides, and their prepared methods are described. Several strategies (e.g., nanostructure designs, elemental doping, tuning morphologies, crystallinity and surface defect engineering for improving oxygen vacancies) for modulating their electrochemical performance are also described. The recent progress of their applications in the electrochemical OER and supercapacitors is summarized. Finally, we conclude this review by giving some challenges and future perspectives of DP oxides in renewable energy conversion and energy storage devices.