Phase Engineering and Alkali Cation Stabilization for 1T Molybdenum Dichalcogenides Monolayers

Abstract

The technological barriers of the dimensional engineering and interfacial instability seriously hinder the scalable production of metallic (1T) transition metal dichalcogenides (TMD) monolayers. In this article, a facile and fast electron injection strategy is developed to modulate the d orbits of Mo center in trigonal prismatic 2H phases (MoS 2 and MoSe 2 ); meanwhile various cations (Li + , Na + , and K + ) reinforce the in-plane 1T-atomic arrangement and expand the out-of-plane spacing for easy exfoliation. Theoretical and experimental evaluations further elucidate the decisive electron-donating capability and suitable ionic radius in stabilizing 1T coordination. The astailored 1T-MoS 2 /MoSe 2 anodes can achieve the robust Na + storage in the half cells (5000 cycles at 5 A g -1 ) and extreme power output of 3134.9 W kg -1 in the full cell. This phase-engineering approach enables the precise dimensional manipulation of the 1T TMDs, which further extends their application horizons as the cation host for the power-oriented battery systems.

Percolating Superconductivity in Air‐Stable Organic‐Ion Intercalated MoS2

“…The position of the Mo 3p peaks does not significantly change after the intercalation, indicating that (CTA) x MoS 2 and (TEA) y MoS 2 retain the pristine trigonal prismatic phase (2H). [42][43][44] This is further confirmed by a micro-Raman characterization of the crystals, which shows no traces of the 1T/1T' phase (Figure S4, Supporting Information). Additionally, the width of the Mo peaks in the XPS spectrum of the intercalates is 1.7 times larger than that of the pristine crystal, suggesting that the physicochemical environment of the Mo atoms is not homogeneous across the surface, producing slightly shifted components in the Mo peak that overall result in a larger width.…”

Optimization of the NH2-UiO-66@MoS2 heterostructure for enhanced photocatalytic hydrogen evolution performance

“…3b), corresponding well with the PXRD results. 34 Material characterization results reveal the high phase purity of the synthesized composites. Meanwhile, the thermal stability of the composites was evaluated through TG analysis conducted from 25 to 800 °C (Fig.…”

Defect engineering of two-dimensional materials for advanced energy conversion and storage

“…Each TMD atomic layer presents a lamellar structure with a transition metal layer molecularly bonded between two chalcogen layers, forming various stacked polytypes including the thermodynamically stable trigonal prismatic coordination (2H), metastable octahedral coordination (1T), and prismatic (3R) phases. 11 Moreover, Mo atomic planes bonded in the metallic 1T phase can be distorted into zigzag chains to form a disordered 1T 0 phase. For the well-studied 2H-MoS 2 , the electroactive sites only locate at the sulfur edges with an armchair or zigzag coordination, while both the edges and most basal planes of metallic 1T/1T 0 -MoS 2 nanosheets are electrochemically active.…”

“…7 In particular, two-dimensional (2D) materials, such as graphene, transition metal dichalcogenides (TMDs), MXene and black phosphorus (BP), have emerged as promising electrode materials for next-generation catalytic/electrochemical systems. [7][8][9][10][11][12][13][14][15] The distinct structural architectures (e.g., planar, buckling, and puckered structures) and ultrahigh specific surface area endow 2D materials with various attractive merits, including short ion transport pathways, low ion diffusion barriers, tunable electronic structures, and large surface interactions. [16][17][18] However, the dimensionality reduction of materials inevitably brings some intrinsic structure and property limitations compared with their bulk electrode counterparts.…”