Chemical Functionalisation of 2D Materials by Batch and Continuous Hydrothermal Flow Synthesis

Abstract

2D materials are single or few layered materials consisting of one or several elements with a thickness of a few nanometres. Their unique, tuneable physical and chemical properties including ease of chemical functionalisation makes this class of materials useful in a variety of technological applications. The feasibility of 2D materials strongly depends on better synthetic approaches to improve properties, increase performance, durability and reduce costs. As such, in the synthesis of nanomaterials, hydrothermal processes are widely adopted through a precursor–product synthesis route. This method includes batch or continuous flow systems, both employing water at elevated temperatures (above boiling point) and pressures to fine‐tune the physical, chemical, optical and electronic properties of the nanomaterial. Both techniques yield particles with different morphology, size and surface area due to different mechanisms of particle formation. In this Minireview, we present batch and continuous hydrothermal flow synthesis of a selection of 2D derivatives (graphene, MXene and molybdenum disulfide), their chemical functionalisation as an advantageous approach in exploring properties of these materials as well as the benefits and challenges of employing these processes, and an outlook for further research.

Wrinkled Flower-Like rGO intercalated with Ni(OH)2 and MnO2 as High-Performing Supercapacitor Electrode

“…A high-temperature and pressure-driven hydrothermal process along with the strong van der Waals forces might be the reasons behind the way they are folded. 41 Furthermore, the presence of extremely disordered and randomly distributed hexagonal petal like nanoflakes were seen all over the hybrid structure as shown in the inset of the Figure 2 a. The flakes are in the range of 80 to 90 nm in diameter with visible edges, and they tend to be layered or overlapped to construct the wrinkled flower-like shape.…”

Recent advances in the fabrication of 2D metal oxides

“…When the reaction temperature of the closed system is above the boiling point of the solvent system, the high temperature and pressure environment promotes the reaction in the system, and 2D nanosheets are constructed under the induction of catalysts or surfactants. Finally, ultrathin 2D metal oxide nanosheets with good crystallization are obtained after removing surfactants by filtration and centrifugation ( Alli et al., 2020 ; Sun et al., 2014 ). Based on this generalized synthesis strategy, ultrathin 2D MOXs (TiO 2 [ Lan et al., 2018 ], ZnO [ Sahu et al., 2018 ], MoO 3 [ Alsaif et al., 2014 ], and WO 3 [ Khan et al., 2017 ]) have been successfully synthesized.…”

Bottom-Up Engineering Strategies for High-Performance Thermoelectric Materials

“…Aqueous solution-based hydrothermal synthesis has been widely used for the synthesis of 2D type transition metal dichalcogenides [188][189][190].…”

“…Aqueous solution-based hydrothermal synthesis has been widely used for the synthesis of 2D type transition metal dichalcogenides [ 188 – 190 ]. Hydrothermal synthesis of 2D materials can provide different structure and morphology, affording a new pathway to change the carrier mobility and concentration, making the synthesized 2D materials as a good candidate for TE applications.…”