Phase Engineering from 2H to 1T-MoS<sub>2</sub> for Efficient Ammonia PL Sensor and Electrocatalyst for Hydrogen Evolution Reaction

Chacko, Levna; Rastogi, Pankaj Kumar; Aneesh, P. M.

doi:10.1149/2.0071908jes

Cited by 31 publications

(19 citation statements)

References 49 publications

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“…These results were validated by UV–vis measurements of the MoS 2 dispersion, shown in Figure b, which are in agreement with previously reported results . The peak observed between 350 and 450 nm indicates a direct excitonic transition from the valence to the conduction band and is enhanced upon transforming 1T MoS 2 to the 2H polymorph through heat treatment . Similarly, the peaks observed at ∼610 nm and ∼660 nm correspond to B1 and A1 direct excitonic transitions in 2H MoS 2 , respectively.…”

Section: Results and Discussionsupporting

confidence: 92%

“…6 The peak observed between 350 and 450 nm indicates a direct excitonic transition from the valence to the conduction band and is enhanced upon transforming 1T MoS 2 to the 2H polymorph through heat treatment. 38 Similarly, the peaks observed at ∼610 nm and ∼660 nm correspond to B1 and A1 direct excitonic transitions in 2H MoS 2 , respectively. The peaks at ∼610 and ∼660 nm were only observed in the 2H MoS 2 sample.…”

Section: Resultsmentioning

confidence: 93%

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Intrinsic Capacitance of Molybdenum Disulfide

Chen

Walker

et al. 2020

ACS Nano

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The metallic, 1T polymorph of molybdenum disulfide (MoS2) is promising for next-generation supercapacitors due to its high theoretical surface area and density which lead to high volumetric capacitance. Despite this, there are few fundamental works examining the double-layer charging mechanisms at the MoS2/electrolyte interface. This study examines the potential-dependent and frequency-dependent area-specific double-layer capacitance (C a) of the 1T and 2H polymorphs of MoS2 in aqueous and organic electrolytes. Furthermore, we investigate restacking effects and possible intercalation-like mechanisms in multilayer films. To minimize the uncertainties associated with porous electrodes, we carry out measurements using effectively nonporous monolayers of MoS2 and contrast their behavior with reduced graphene oxide deposited layer-by-layer on atomically flat graphite single crystals using a modified, barrier-free Langmuir–Blodgett method. The metallic 1T polymorph of MoS2 (C a,1T = 14.9 μF/cm2) is shown to have over 10-fold the capacitance of the semiconducting 2H polymorph (C a,2H = 1.35 μF/cm2) near the open circuit potential and under negative polarization in aqueous electrolyte. However, under positive polarization the capacitance is significantly reduced and behaves similarly to the 2H polymorph. The capacitance of 1T MoS2 scales with layer number, even at high frequency, suggesting easy and rapid ion penetration between the restacked sheets. This model system allows us to determine capacitance limits for MoS2 and suggest strategies to increase the energy density of devices made from this promising material.

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Section: Results and Discussionsupporting

confidence: 92%

Section: Resultsmentioning

confidence: 93%

Intrinsic Capacitance of Molybdenum Disulfide

Chen

Walker

et al. 2020

ACS Nano

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“…46 Bulk MoS 2 has 1.2 eV of indirect band gap whereas exfoliated MoS 2 , which makes a transition from indirect band gap to direct band gap of 1.8 eV, has enhanced PL owing to relaxation-of-excitons at Brillouin zone K point. 47 It is observed in 2D MoS 2 nanosheets that an increase in excitation wavelength proceeds to a redshi in PL spectrum with l-range from 480 to 540 nm. This observation is associated to the excitation dependent PL is related with poly-dispersity of two-dimensional nanosheets.…”

Section: Resultsmentioning

confidence: 98%

Promising performance of chemically exfoliated Zr-doped MoS₂ nanosheets for catalytic and antibacterial applications

et al. 2020

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“…Different methods are adopted to enhance the inherent HER activity of 2H‐MoS 2 (which is thermodynamically more stable than its structural polymorph 1T MoS 2 ) . However, the 2H phase shows semiconducting nature, whereas the 1T phase has a metallic nature . Furthermore, it is reported that 1T‐MoS 2 has higher hydrophilicity, which eventually directs the maximum interaction with the electrolyte .…”

Section: Comparison Of Tafel Slopes Of Triangles and Dendritesmentioning

confidence: 99%

“…[38] However, the 2H phase shows semiconducting nature, whereas the 1T phase has a metallic nature. [38,39] Furthermore, it is reported that 1T-MoS 2 has higher hydrophilicity, which eventually directs the maximum interaction with the electrolyte. [40] Furthermore, unlike in 2H-MoS 2 , the basal plane of 1T-MoS 2 is also HER active.…”

mentioning

confidence: 99%

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

Sharma

Sahoo

Rastogi

et al. 2019

Physica Rapid Research Ltrs

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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.

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Phase Engineering from 2H to 1T-MoS₂ for Efficient Ammonia PL Sensor and Electrocatalyst for Hydrogen Evolution Reaction

Cited by 31 publications

References 49 publications

Intrinsic Capacitance of Molybdenum Disulfide

Intrinsic Capacitance of Molybdenum Disulfide

Promising performance of chemically exfoliated Zr-doped MoS₂ nanosheets for catalytic and antibacterial applications

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

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Phase Engineering from 2H to 1T-MoS2 for Efficient Ammonia PL Sensor and Electrocatalyst for Hydrogen Evolution Reaction

Cited by 31 publications

References 49 publications

Intrinsic Capacitance of Molybdenum Disulfide

Intrinsic Capacitance of Molybdenum Disulfide

Promising performance of chemically exfoliated Zr-doped MoS2 nanosheets for catalytic and antibacterial applications

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

Contact Info

Product

Resources

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Phase Engineering from 2H to 1T-MoS₂ for Efficient Ammonia PL Sensor and Electrocatalyst for Hydrogen Evolution Reaction

Promising performance of chemically exfoliated Zr-doped MoS₂ nanosheets for catalytic and antibacterial applications