Halogen Functionalization in the 2D Material Flatland: Strategies, Properties, and Applications

Abstract

Given the electronegativity and bonding environment of halogen elements, halogenation (i.e., fluorination, chlorination, bromination, and iodination) serves as a versatile strategy for chemical modifications of materials. The combination of halogens and 2D materials has triggered extensive interests since the first report on graphene fluorination in 2008. Subsequently, scholars consistently conduct pre‐, in‐process, or posthalogenation modifications of emerging 2D materials to achieve desired properties and broad device applications. They also continuously explore the role of halogens in 2D material functionalization. The multiple advantages introduced by halogen decoration make 2D materials outstanding from each subclass. In this review, an overall retrospect is provided on the research advances in the area of 2D material halogenation, including experimental halogenation strategies, halogen‐triggered novel physics and properties, and advanced applications across the studied objects. Future research directions in this area are also proposed.

Enhanced photocatalytic activity of TiO2/UiO-67 under visible-light for aflatoxin B1 degradation

“…We further evaluated the band gap energy of the samples according to Tauc curve: ( αhν ) = A ( hν − E g ) n /2 , where α , E g , h , ν and A are the absorption coefficient, band gap energy, Planck's constant, optical frequency and constant, respectively. 43 The corresponding bandgaps of T-10%U, TiO 2 and UiO-67 are 2.21 eV, 3.18 eV, and 3.14 eV, respectively ( Fig. 4a and b ).…”

Advances in the Synthesis of 2D MXenes

“…Since the successful exfoliation of 2D graphene nanosheets from bulk graphite in 2004, [1,2] research attention has been diverted to various 2D materials such as transition metal dichalcogenides (TMDs), black phosphorus (BP), and layered double hydroxides (LDHs) with superior electrical, optical, and magnetic properties. [3][4][5][6][7][8][9] Among these 2D materials, transition metal carbides, nitrides, and carbonitrides, known as MXenes, were first reported in 2011 (Ti 3 C 2 T x ) and have seen a proportionate expansion in their synthesis and application during the past decade. [10][11][12][13][14] MXenes are commonly synthesized using a topdown etching process with layered ternary MAX phase as precursors.…”

Enhanced stability and tunable optoelectronic properties of silicon–carbon monolayers by strain and surface functionalization

“…On the other hand, chemical functionalization 31 (like fluorination and hydrogenation) on 2D materials is also a mature technology, which has been realized in graphene 32,33 and germanene. 34,35 As a result, we applied biaxial tensile strain and fluorination on the Si 2 C monolayer to investigate its stability and electronic and optical properties by employing density-functional and many-body perturbation theories.…”