Synthesis, processing, and applications of 2D (nano)materials: A sustainable approach

Two-dimensional (2D) nanomaterials have the potential to change the world by providing materials with advanced functional applications. The 2D nanomaterials i.e., graphene and its derivative, graphene nanosheets, graphene nanoplatelets, metal-organic frameworks (MOFs), transition metal dichalcogenides, MXenes, covalent organic frameworks (COFs), hexagonal boron nitride (h-BN), etc. find applications in energy storage devices, hybrid capacitors, supercapacitors, photovoltaic cells, sensors, photoluminescent devices, semiconductors, diodes, transistors, room temperature superconductor, anti-corrosive coating, insulating materials, etc. In this review article, we have focussed on different synthetic approaches, designs, and processing methods of 2D nanomaterials. Different practices for synthesizing 2D nanomaterials like ultrasonic exfoliation, Hummers, chemical vapor deposition, hydrothermal/solvothermal, micromechanical exfoliation, ligand-assisted approach, small molecule mediated synthesis, etc. were discussed. For designing 2D nanomaterials of desired properties, one has better control over the processing method because the properties of nanomaterials vary a lot depending upon their size-to-volume ratio, exfoliation technique, thickness and dimension of the 2D sheet, porous and nonporous character, percentage of organic and inorganic content, etc. Emphases have been made on the effect of surface properties on physical, mechanical, optical, and electrical properties and applications of 2D nanomaterials. A few important applications of 2D nanomaterials were also discussed. This review article is a holistic approach including social, economic, and ecological aspects in the synthesis of 2D nanomaterials and will certainly help in designing fabrication, and application-specific 2D nanomaterials for different nanodevices.