Host–Guest Intercalation Chemistry for the Synthesis and Modification of Two‐Dimensional Transition Metal Dichalcogenides

Abstract

Intercalation chemistry is of great importance in solid‐state physics and chemistry for the ability to modulate electronic structures for constructing new materials with exotic properties. This ancient and versatile discipline has recently become prevailing in the synthesis and regulation of 2D transition metal dichalcogenides (TMDs) with atomic thickness due to diverse host–guest configurations and their impact on layered frameworks, which bring in extensive applications in electronics, optoelectronics, and other energy‐based devices. In order to prepare 2D TMD materials with desired structure and properties, it is essential to gain in‐depth understanding of the key role the intercalation chemistry plays in the preparation process. A focused review on recent advances regarding 2D TMD materials through intercalation exfoliation from the view of host, guest, and solvent interactions is provided. The effect of intercalation chemistry on TMD nanosheets synthesis and modification is comprehensively reviewed. The interactions between host and guest from the aspects of lattice strain, interlayer distance, and carrier density are considered. Finally, a prospectus of the future research opportunities for the intercalation chemistry of 2D materials is provided.

Structure modulation of two-dimensional transition metal chalcogenides: recent advances in methodology, mechanism and applications

“…Intercalated species, such as alkali metal atoms (or ions), ammonium ions or molecules, can be driven to intercalate into adjacent TMD layers and weaken the interlayer interactions, which are widely studied in the fields of liquid exfoliating synthesis and energy storage applications. [48][49][50][51][52] Intercalated species are beneficial to construct a series of superlattices or induce the phase transition. 3,17,[49][50][51]53 For instance, Li-intercalated 2H-MX 2 will be transformed into Li x MX 2 , which endows the possibility of phase transition to 1T-MX 2 .…”

“…[48][49][50][51][52] Intercalated species are beneficial to construct a series of superlattices or induce the phase transition. 3,17,[49][50][51]53 For instance, Li-intercalated 2H-MX 2 will be transformed into Li x MX 2 , which endows the possibility of phase transition to 1T-MX 2 . 3,49,51 Apparently, the partial intercalation of few-layer H-phase TMDs can be further transformed into lateral heterostructures based on different polymorphs.…”

“…3,17,[49][50][51]53 For instance, Li-intercalated 2H-MX 2 will be transformed into Li x MX 2 , which endows the possibility of phase transition to 1T-MX 2 . 3,49,51 Apparently, the partial intercalation of few-layer H-phase TMDs can be further transformed into lateral heterostructures based on different polymorphs. 17,54 In contrast to the commonly used intercalants, transition metal ions exhibit special behaviours, i.e., the transformation from layered TMDs to bulk materials, which further affect their electrical properties.…”

Phonon anharmonicity and thermal conductivity of two-dimensional van der Waals materials: A review

“…For instance, the high anisotropy of monolayer phosphorene [6], the large (1.9 eV) direct band gap in monolayer MoS2 [7][8][9], and the excellent ductility of atomically thin vdW materials [10] are just typical examples of abnormal behaviors in the atomic limit. Many review papers have been published on the new physical properties associated with thickness reduction, particularly for graphene [11][12][13], transition metal dichalcogenides (TMDs) [14][15][16][17], and black phosphorus [14,[18][19][20]. Therefore, those aspects are not discussed in detail here.…”

Re Modulation of Metallic Ultrathin 2M-WS2 for Highly Efficient Hydrogen Evolution in Both Acidic and Alkaline Media

“…Notably, typical TMDs have a layered structure similar to graphite. The adjacent layers are weakly bound by van der Waals force, while the strong S-metal-S covalent bonds control the inner frame of the layer. − This unique structure endows TMDs with unique exfoliative characteristics and plenty of tunable active sites, which can be modulated to improve the electron transfer property, enhance the activity, and accelerate the catalytic reaction. ,− Compared with typical MoS 2 catalyst, WS 2 has longer W–S bonds with relatively small structural lattice stress and higher hydrogen adsorption activity on S-terminated edge sites, which is regarded as a promising HER electrocatalyst. − Different coordination forms of WS 2 will produce a variety of phase structures, such as 3R (orthorhombic structure), 2H (hexagonal structure), and 1T (trigonal structure). ,− The Jahn–Teller distortion of octahedral coordination in 1T-phase WS 2 will further cause the phase transition to form a triangular cluster stacking 1T″′ structure and a zigzag chain-like 1T′ structure (2M phase). − …”