Surface engineering of MXenes for energy and environmental applications

Abstract

MXenes, a new family of two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides, have received considerable attention in the energy and environmental applications due to their intriguing electronic, electrochemical, optical, and...

Ion-Selective Separation Using MXene-Based Membranes: A Review

“…48−52 Besides, given that the Aelement in MAX phases and the Lewis acid molten salt cation could form direct redox coupling, this method was further extended for etching other MAX phases with different Aelements apart from Al, e.g., Al, Zn, Si, and Ga. More importantly, surface functional groups such as −O, −OH, −F, −Cl, −NH 3 , or −NH 4 + , tailored by employed etching agents, can have a crucial impact on physicochemical properties as well as electrochemical behaviors such as work function. 53,54 The −OH termination can improve the chemisorption of Ti 3 C 2 T x MXene through the ion exchange process. 55 ■ FABRICATION AND PROPERTIES OF 2D MXENE MEMBRANES 2D MXene can be constructed into membranes for ionic or molecular separation due to their intriguing features such as hydrophilicity, abundant surface terminal groups, and structural and chemical tunability.…”

“…In this regard, many HF-free etching methods have been recently reported, including hydrothermal etching, , electrochemical etching, and molten salt etching. , The latter method, in particular, which may involve the use of Lewis acid–based etching, has allowed for the synthesis of MXenes terminated with other functional species (e.g., Cl and S) (Figure D). For example, transition metal halides, such as CdCl 2 , CdBr 2 , ZnCl 2 , and CuCl 2 have been studied for Lewis acid etching, leaving behind halogen terminal groups. − Besides, given that the A-element in MAX phases and the Lewis acid molten salt cation could form direct redox coupling, this method was further extended for etching other MAX phases with different A-elements apart from Al, e.g., Al, Zn, Si, and Ga. More importantly, surface functional groups such as −O, −OH, −F, −Cl, −NH 3 , or −NH 4 + , tailored by employed etching agents, can have a crucial impact on physicochemical properties as well as electrochemical behaviors such as work function. , The −OH termination can improve the chemisorption of Ti 3 C 2 T x MXene through the ion exchange process …”

Advances and emerging challenges in MXenes and their nanocomposites for biosensing applications

“…MXenes have a large effective surface area and ample surface terminations with a facile possibility to be externally modied, thus they can serve as an effective platform for biomolecules immobilization. [158][159][160] In addition to this, AuNPs supported by MXene nano sheets introduce thiol-Au bonding features, so that the observed increase in DNA surface density on AuNPs@MXene/Au can be ascribed to the well-distributed AuNPs within and on the MXene layers. In addition, the enhanced charged mobility and high electrocatalytic ability of MXenes elevates the electrochemical signal by four times.…”

Poly(p-phenylene vinylene) incorporated into carbon nanostructures

“…Modern technologies, especially focused on searching for new energy sources, storing energy or processing it, require the creation and research of new materials, cheaper, more durable and exhibiting desirable physicochemical properties. These new electro-technically useful materials include covalent organic frameworks [1,2], metal-organic frameworks [3][4][5] or transition metal MXenes [6][7][8]. Traditional materials that have been used for many years in devices for generating, Abstract Composites of poly(p-phenylene vinylene) (PPV) and different carbon nanostructures, such as fullerene C 60 , multi-walled carbon nanotubes (MWC-NTs), single-walled carbon nanotubes (SWCNTs), graphene oxide (GO), and graphene nanoplatelets (GNPLs), were produced by Wittig's soluble precursor procedure in solutions containing dispersed particles of carbon nanomaterials.…”