Enhanced Photocatalytic Activity in 2D‐1D WS2/TiO2 and 2D‐2D MoS2/WS2 Heterosystems

Abstract

Two‐dimensional (2D) tungsten disulphide (WS2) based heterostructures with modified interfaces have huge potential for photocatalytic applications. Integrating WS2 with one‐dimensional (1D) titanium dioxide (TiO2) and 2D molybdenum disulphide (MoS2) structures to form heterostructures, enhances its photocatalytic activity. The enrichment in photocatalytic activity of heterostructures may get affected by the electronic interaction at the interface as well as morphology and dimensionality also affect the catalytic activity. In this context, the present work focuses on the enrichment of photocatalytic activity by different tungsten disulphide (WS2) based heterostructures, which may get influenced by the interfacial interaction. In the present work, two different heterostructures 2D‐1D WS2/TiO2 and 2D‐2D MoS2/WS2 are formed using the hydrothermal method. Scanning electron microscopy (SEM) confirmed the morphology of prepared heterostructures. X‐ray photoelectron spectroscopy (XPS) analysis further revealed that the integration of 1D and 2D nanostructures with WS2 has been found effective to alter the interface by the development of the Ohmic and Schottky barrier. Moreover, Fourier transformation infra‐red (FTIR) spectroscopy confirms the presence of W−S, S−S, Mo−S, and Ti−O bonds in the prepared heterostructures. Furthermore, current‐voltage (I–V) data graphically illustrated the conductivity of catalysts. I–V curves confirm the presence of Schottky and ohmic barriers and the higher electrical conductivity of 2D‐2D MoS2/WS2 heterostructures, which facilitates the charge carrier's transportation. 2D‐1D WS2/TiO2 and 2D‐2D MoS2/WS2 heterostructures are further explored for photocatalytic activity by the methylene blue dye degradation. The overall catalytic activity of 2D‐2D MoS2/WS2 is better than 2D‐1D WS2/TiO2 and WS2, respectively. This result was accounted as 2D‐2D MoS2/WS2 had the highest conductivity and better charge separation at the interface in comparison to the other two synthesised catalysts.

Full text

Enhanced Photocatalytic Activity in 2D-1D WS2/TiO2and
2D-2D MoS2/WS2Heterosystems
Deepali Aswal,[a] Priyanka Bamola,[a] Chanchal Rani,[b] Saurabh Rawat,[a] Abhinav Bhatt,[a]
Sandeep Chhoker,[c] Mohit Sharma,[d] Charu Dwivedi,[e] Rajesh Kumar,*[b] and
Himani Sharma*[a]
Two-dimensional (2D) tungsten disulphide (WS2) based hetero-
structures with modified interfaces have huge potential for
photocatalytic applications. Integrating WS2with one-dimen-
sional (1D) titanium dioxide (TiO2) and 2D molybdenum
disulphide (MoS2) structures to form heterostructures, enhances
its photocatalytic activity. The enrichment in photocatalytic
activity of heterostructures may get affected by the electronic
interaction at the interface as well as morphology and
dimensionality also affect the catalytic activity. In this context,
the present work focuses on the enrichment of photocatalytic
activity by different tungsten disulphide (WS2) based hetero-
structures, which may get influenced by the interfacial
interaction. In the present work, two different heterostructures
2D-1D WS2/TiO2and 2D-2D MoS2/WS2are formed using the
hydrothermal method. Scanning electron microscopy (SEM)
confirmed the morphology of prepared heterostructures. X-ray
photoelectron spectroscopy (XPS) analysis further revealed that
the integration of 1D and 2D nanostructures with WS2has been
found effective to alter the interface by the development of the
Ohmic and Schottky barrier. Moreover, Fourier transformation
infra-red (FTIR) spectroscopy confirms the presence of WS,
SS, MoS, and TiO bonds in the prepared heterostructures.
Furthermore, current-voltage (I–V) data graphically illustrated
the conductivity of catalysts. I–V curves confirm the presence of
Schottky and ohmic barriers and the higher electrical con-
ductivity of 2D-2D MoS2/WS2heterostructures, which facilitates
the charge carrier’s transportation. 2D-1D WS2/TiO2and 2D-2D
MoS2/WS2heterostructures are further explored for photo-
catalytic activity by the methylene blue dye degradation. The
overall catalytic activity of 2D-2D MoS2/WS2is better than 2D-
1D WS2/TiO2and WS2, respectively. This result was accounted as
2D-2D MoS2/WS2had the highest conductivity and better
charge separation at the interface in comparison to the other
two synthesised catalysts.
Introduction
The aromatic organic compounds that impart colour to the
visible region through the absorption of light are called dyes.[1,2]
Their permanent colour and resistance to fading on exposure to
light, oxidizing agents, water, and microbial attack have made
them an essential amenity in many industrial applications.[3,4] As
a result, these dyes end up in water bodies, generating a
tremendous amount of wastewater containing carcinogenic
and toxic dyes that are unfit for human consumption.[3,5] One
such dye is MB (methylene blue), extensively used in the textile
industry.[6] It is highly water-soluble and thus forms a stable
solution with water at room temperature.[3,4,7,8] With various
hazardous impacts, it’s vital to remove MB from industrial
wastewater. Following this, researchers reported the removal of
MB via absorption[9,10] and bioremediation.[11] Advancements in
this field later led to a more efficient technique, the photo-
degradation of MB using various nano catalysts. The research
work explores the domain of the use of semiconductor nano-
particles as photocatalysts for the photodegradation of organic
pollutants (i. e., MB). Being cost-effective, easy, environmental
friendly, and having the added advantage of non-toxic by-
products from the oxidation of MB has received attention for
wastewater treatment.[4,12] The work is centred on the influence
of the different semiconductor morphologies (1D, 2D, and 3D)
as photocatalysts in the photodegradation of MB from waste-
water. Accomplishing very high productivity with less complex-
ity is always a challenge for adequate photocatalysts. In this
context, semiconductors, and transition metal dichalcogenides
(TMDCs) can be used as photocatalysts. Both possess an energy
band gap that needs visible light to shift electrons from the
valance band (HOMO) to the conduction band (LUMO). Also,
they are non-toxic, chemically stable, accessible at a sensible
cost, and competent for repeated use without considerable loss
of catalytic ability.[6]
Among distinctive monolayer TMDCs, WS2(tungsten disul-
fide) captivates the most, it possesses an indirect band gap
[a] D. Aswal, P. Bamola, S. Rawat, A. Bhatt, H. Sharma
Functional Nanomaterials Research Laboratory, Department of Physics,
Doon University, Dehradun, Uttarakhand – 248001, India
E-mail: hsharma.ph@doonuniversity.ac.in
[b] C. Rani, R. Kumar
Materials and Device Laboratory, Department of Physics, Indian Institute of
Technology, Indore, 453552, India
E-mail: rajeshkumar@iiti.ac.in
[c] S. Chhoker
Department of Physics and Materials Science and Engineering, Jaypee
Institute of Information Technology, Noida, 201307, India
[d] M. Sharma
Institute of Materials Research and Engineering, A*STAR (Agency for
Science, Technology and Research), 2 Fusionopolis Way, Innovis, No. 08–03,
Singapore 138634, Singapore
[e] C. Dwivedi
Department of Chemistry, Doon University Dehradun, Dehradun, Uttarak-
hand – 248001, India
Wiley VCH Montag, 11.09.2023
2334 / 318580 [S. 588/597] 1
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Research Article
doi.org/10.1002/slct.202204998