Harnessing transition metal oxide-carbon heterostructures: Pioneering electrocatalysts for energy systems and other applications

Exponential demand for energy resources and fossil fuel substitution with green alternatives are essential to bringing sustainable development and a solution to the energy crisis. Transition metal oxides (TMOs) and their composites (TMOCs) as promising electrocatalysts to develop potential energy conversion and storage devices contribute to the solution to this crisis. The productivity of green fuels such as hydrogen from water-splitting reactions, the efficiency of energy storage and harvesting devices including supercapacitors and batteries, and the performance of electrochemical sensors can be remarkably enhanced with TMOs and their composites. Excellent electrochemical attributes, stability, abundant reserves, low cost, environment-friendly, and low toxicity make TMOs and their composites an excellent choice. The tunability of the physical and chemical properties of TMOs makes them attractive for research in designing different energy storage devices. This review presents a concise overview of the unique physical and electrochemical aspects of various TMOs and TMOCs, such as spinels, perovskites, and TMO-integrated carbon-based compounds, and their relevance for specific applications, emphasizing energy-related fields. The recent research advancements of TMOs-based functional materials for emerging applications, such as water splitting, fuel cells, supercapacitors, batteries, and sensing, are discussed. This review also highlights the advantageous properties and pertinent fabrication methods of TMOs and TMOCs for electrocatalysis, along with the methods to enhance their electrocatalytic abilities, which improve the overall efficiency of the desired applications.