Mo Doping Assisting the CVD Synthesis of Size-Controlled, Uniformly Distributed Single-Layer MoS₂ on Rutile TiO₂(110)

Abstract

Molybdenum disulfide (MoS 2 ) has attracted considerable interest due to its superior electronic and optical properties, which have seen promising applications in optoelectronics and catalysis. Chemical vapor deposition (CVD) has been successfully applied in synthesizing MoS 2 on various substrates. However, it remains a great challenge to fabricate high-quality MoS 2 sheets with well-controlled micro/nano size and homogeneous distribution over the functional substrates such as active metal oxides. Herein, we have developed a two-step synthetic strategy via depositing MoO 3 first followed by subsequent vulcanization, to grow single-layer MoS 2 on an atomically flat rutile TiO 2 (110) (r-TiO 2 (110)) substrate. This method not only very well controls the size as well as the spatial distribution of MoS 2 nanosheets over the TiO 2 surface but also averts the formation of contaminative species at the heterojunction while maintaining the atomic structure of the substrate surface. The extensive characterizations reveal that the formation of MoS 2 derives from the sulfurization of the singly dispersed Mo 6+ and Mo 5+ species in the surface/subsurface region instead of the aggregated MoO 3 patches on top of the TiO 2 surface. Such a mechanism may dictate a general way for synthesizing high-quality transition-metal dichalcogenides (TMDs) over a variety of functional substrates.

Few‐Layered MoxW1−xS2‐Modified CdS Photocatalyst: One‐Step Synthesis with Bifunctional Precursors and Improved H2‐Evolution Activity

“…For the Mo element, the MoS 2 /CdS and Mo x W 1− x S 2 /CdS samples show distinct Mo 3 d 5/2 (228.5 eV) and Mo 3 d 3/2 (231.6 eV) peaks that are indexed to the Mo (IV) in MoS 2 and Mo x W 1− x S 2 cocatalysts compared with the conventional CdS, whereas the unavoidable oxidation of the cocatalyst leads to the presence of the Mo (VI) peaks (Mo 3 d 5/2 in 232.5 eV and Mo 3 d 3/2 in 235.6 eV). [ 62–66 ] Noticeably, it is worth mentioning that the intensity of the Mo (IV) peaks undergoes a dramatic decline after introducing W into the Mo x W 1− x S 2 /CdS photocatalyst, evidently implying the successful integration of W into the Mo x W 1− x S 2 cocatalyst (Figure 4B). For further investigation of W element, the W 4 f core‐level spectrum of the Mo x W 1− x S 2 /CdS photocatalyst is shown in Figure 4C.…”

3d transition metal coordination on monolayer MoS2: a facile doping method to functionalize surfaces

“…The presence of Mo 6+ in some pristine and functionalized samples originated from Mo oxide remnants from the CVD synthesis. 26 The S 2p peak in the MoS 2 –Cu sample is shifted to higher energies due to the change in the Mo oxidation state; however, it is still in the typical range of sulfides. 23 For all the S spectra (Fig.…”

2D Molybdenum Sulfide‐Based Materials for Photo‐Excited Antibacterial Application

“…The advantages of this method are fast deposition speed, scalable size, large and uniform film-forming area, controllable thickness, etc. [144,145] However, depending on the significant differences in the vapor pressure of the precursors, the pressure and temperature need to be precisely captured throughout the process to ensure consistent supply. [161] This condition results in poor controllability and reproducibility of experiments.…”

“…[141,142] The latter is based on metal salts as precursors to assemble MoS 2 nanosheets by a series of chemical reactions, [143] which can achieve large-scale production by overcoming the limitation of flake size and yield of exfoliation techniques. The representative methods include chemical vapor deposition (CVD) [144,145] and solvothermal/hydrothermal methods. [146,147]…”