Metal Oxide and Hydroxide-Based Functionalized Nanomaterials as Supercapacitors and Their Environmental Impact

Several scholars and scientists have recently continued their efforts to fabricate and develop advanced nanoscopic optoelectronic devices, supercapacitors, solar systems, and biomedical equipment. Because of the widespread use of chemical and solar energy, energy storage and conversion for multiple uses has increased globally. As a result, hybrid nanomaterials, such as nanotubes, nanowires, nanoclusters, and nano-thin films, have been developed and investigated to address energy-related issues. Semiconducting nanostructures, such as modified metal-oxides or metal-hydroxides, have been designed to improve the work performance of eco-friendly supercapacitors. In this regard, Metal-doped metal-oxides or hydroxide materials supported by superconducting nanomaterials have been highly valued and discovered for controlling and improving the work-functionalities of hybrid supercapacitors. The structural, surface, and optical properties of metal oxides such as Fe2O3/Fe3O4, MnO2, TiO2, ZnO, MoS2, and ZnS, among others, are fundamentally altered by the stoichiometric doping of noble metal, transitional, or rare earth ions, which favour an expected charge recombination rate toward improved supercapacitor progress. In recent years, researchers have focused on the band gap modification and electronic transitions of such modified nanostructures to solve energy storage and communication problems. As a result, this chapter will provide a systematic explanation for the fabrication, design, morphological investigations, and developments of the specific metal-doped semiconducting supercapacitors.