Nanostructured Heterojunction (1D-0D and 2D-0D) Photocatalysts for Environmental Remediation

Global warming and environmental pollution are the most important problems or challenges present in the scientific community. To successfully tackle the environmental problems, the novel nanotechnologies that work with efficient nanomaterials are the only way. Therefore, the development of nanomaterials and their composites with heterojunctions has made great demand in view of the environmental remediation. Hence in this book chapter we have focused on the development of various heterojunction nanomaterials including 1D-0D and 2D-0D heterojunction photocatalysts comprising of various metal oxides and metals for environmental remediation, organic dye degradation, wastewater treatment, air purification, and antibacterial treatments. The 1D-0D heterojunctions consisting of 1D nanostructures like TiO2 nanotubes, nanobelts, ZnO nanorods, metal oxide nanowires with 0D metals, and metal oxides of Cu, CuxO, MnO2, Ag, Ag2O, Au, Pt, etc. were reported emphasizing the special properties associated with the nanostructures like high surface area, abundant active sites, and efficient charge transfer across the interface of the heterojunction. Followed by 2D-0D heterojunctions associated with g-C3N4, rGO and GO nanosheets coupled with metal oxides of Ag2O, Cu2O, ZnO, In2O3, MoO3, V2O5, and TiO2 and various transition and noble metals of Cu, Ag, Au, Pt, Pd, etc. were also reported. The important properties associated with the 2D nanosheets like high surface area and higher electron transport properties and special properties of nanometals like SPR effect and a greater number of active sites on the surface of the nanometal particles were highlighted. Various characterization techniques to investigate the physicochemical properties of those nanomaterials were reported. For example, HR-TEM, XRD, DRS UV-Vis, PL spectra, time-resolved PL spectra, transient photocurrent densities, XPS, etc. are studied which were helpful to investigate the higher photocatalytic efficiencies. Finally, the summary and future prospects of these heterojunction photocatalysts and further improvements are summarized. Therefore, this book chapter will give an overview of different types of heterojunction photocatalysts and their properties associated with improving the catalytic properties for a wide range of readers.