On the Synthesis of Morphology‐Controlled Transition Metal Dichalcogenides via Chemical Vapor Deposition for Electrochemical Hydrogen Generation

Abstract

Shape‐engineered atomically thin transition metal dichalcogenide (TMD) crystals are highly intriguing systems with regard to both fundamental and applied science. Herein, a chemical vapor deposition‐assisted generalized synthesis strategy for the triangular‐ and dendritic‐shaped TMDs and their ternary alloys is proposed, and the TMD structures' potential for electrocatalytic hydrogen evolution reaction (HER) applications is demonstrated. The alloy formation is confirmed via micro‐Raman and photoluminescence studies and further verified using transmission electron microscopy and X‐ray photoelectron spectroscopy. The HER activities of MoS2 and MoSe2 triangles are compared with those of their dendritic structures, and an enormous improvement in terms of overpotential and current density is observed for the dendritic structures. A further enhancement of the HER activity is observed in MoS2(1−x)Se2x triangular and dendritic structures, with dendritic MoS2(1−x)Se2x providing the best activity. The demonstrated nonequilibrium growth technique opens new avenues for the synthesis of morphology‐controlled, large area, complex, and atomically thin TMD structures, which can have unprecedented properties, such as the enormous catalytic activity, tunable luminescence, etc., as presented in this article.

High-Sensitivity Characterization of Ultra-Thin Atomic Layers using Spin-Hall Effect of Light

“…The growth is performed using a two-zone furnace under atmospheric pressure with precursor (MoO 3 ) placed at 700 • C and sulfur at 200 • C. A constant flow rate of nitrogen gas was maintained at 185 sccm inside the furnace. Typically, a Si/SiO 2 (300 nm) substrate is placed on top of the precursor where the MoS 2 monolayers will form [32,33]. The MoS 2 sample formed by the above process was characterized using micro Raman spectroscopy as shown in Fig.…”

Molybdenum disulfide–graphene van der Waals heterostructures as stable and sensitive electrochemical sensing platforms

“…CVD technique was used for the growth of monolayer MoS 2 triangular crystals over 300 nm SiO 2 /Si wafer, as discussed in our previous report [5]. Large-area monolayer graphene was grown in a horizontal muffle attached with a quartz tube (1 m long and 5.08 cm diameter).…”

“…Being a highly explored transition metal dichalcogenide, molybdenum disulfide (MoS 2 ) has been extensively studied for its potential in biomedical applications, and these include the sensing of molecules such as dopamine (DA), ascorbic acid (AA) and glucose, and biomarker and deoxyribonucleic acid (DNA) detections [1][2][3].The atomically thin surface of MoS 2 with trigonal prismatic geometry allows the molecules to sit on its surface [4,5], and the negative charge on its surface makes it feasible for selective detection, too [1]. The electrochemical stability of its layers in a large voltage window opens its possibility as an electrochemical sensing platform, too [6].…”

One-Dimensional Hollow Structures of 2O-PdS2 Decorated Carbon for Water Electrolysis

“…4,5 Furthermore, recent studies also show that high mass loading of a large surface area nanocatalyst can lead to mass transfer limitation in the heterogeneous catalytic process, leading to low turnover frequency from the catalyst, and hence, active nanocatalysts having low mass loading are highly preferred from a theoretical (inherent activity) perspective too. 6 Recently, various transition metal based electrocatalysts such as carbides, 7 sulfides, 8 and so on were proposed for the HER process, and some of them were reported as on par in performance with the noble metals such as Pt, Pd, and so on in acidic conditions. Transition metal dichalcogenides (TMDs) such as MoS 2 , MoSe 2 , WS 2 , and WSe 2 , etc., are a few among them, where they are interesting due to their high surface area, two-dimensional (2D) structure.…”