The enhanced photocatalytic performance of SnS₂@MoS₂ QDs with highly-efficient charge transfer and visible light utilization for selective reduction of mythlen-blue

Abstract

Molybdenum disulfide (MoS2) has recently been considered as an effective material for potential photocatalytic applications; however, its photocatalytic activity was limited due to the low density of active sites. In this work, MoS2 Quantum dots (QDs) were synthesized via the ultrasonication technique to construct heterostructure with SnS2 nanosheets (SnS2@MoS2 QDs) and the prepared materials were tested for photocatalytic applications for Methylene blue (MB). Pristine SnS2 and SnS2@MoS2 QDs nanocomposite were analyzed by XRD, TEM, PL, and Uv–Vis. Both SnS2 and SnS2@MoS2 QDs exhibited a single trigonal phase with the P-3m1 space group. The TEM analysis confirmed the coupling between the pristine SnS2 and SnS2@MoS2 QDs. The results of photocatalytic activity toward MB indicated that SnS2@MoS2 QDs material exhibits much superior photocatalytic performance compared to pristine SnS2. The excellent photodegradation performance of SnS2@MoS2 QDs is due in the main to the formation of heterojunction between SnS2 and MoS2 QDs with narrow bandgap formation, which results in a facile carriers transfer and thus high photocatalytic efficiency. A representative mechanism of the photodegradation for SnS2@MoS2 QDs photocatalyst was proposed. Such an ultrasonic technique is capable of producing small metallic particle size that can be used to construct new heterostructures for water remediation applications.

Phonon and Carrier Transport Properties in Low-Cost and Environmentally Friendly SnS2: A Promising Thermoelectric Material

“…Since the hydrothermal and solvothermal method has strong operability and adjustability, it can be used to prepare SnS 2 particles with different shapes and sizes. As shown in Figure b, Sn-containing precursors such as SnCl 2 ·2H 2 O or SnCl 4 ·5H 2 O and S-containing precursors such as thioacetamide (C 2 H 5 NS) or thiourea (CH 4 N 2 S) are used as raw materials, and deionized water or other solvents such as ethanol or isopropanol are used as the reaction medium. − Raw materials and deionized water or other solvents are mixed in a certain order and stirred for several minutes to a few hours to obtain a homogeneous solution, and then the solution is transferred into a Teflon-lined stainless steel autoclave and usually heated at 473 K for several hours. − In the process of synthesis, high vapor pressure can be achieved in the sealing vessel due to the reaction temperature being higher than the boiling point of the mixed solution. Therefore, the precursors in this environment will be decomposed into tin ions and sulfur ions, and the reaction between the ions will form SnS 2 crystal nuclei, which will become the core of crystal growth.…”

“…Therefore, the precursors in this environment will be decomposed into tin ions and sulfur ions, and the reaction between the ions will form SnS 2 crystal nuclei, which will become the core of crystal growth. When the reaction is finished, 2H-SnS 2 will usually be obtained after the processes of centrifugation and washing with deionized water and drying in a vacuum oven. − …”

Hydrothermal Synthesis of MoS2/SnS2 Photocatalysts with Heterogeneous Structures Enhances Photocatalytic Activity

“…MoS 2 has a graphene-like layered structure with three crystal phases: 1T, 2H and 3R [ 16 ]. In a natural state, MoS 2 is usually present in the steady 2H phase, which exhibits semiconducting properties [ 17 , 18 ]. However, the low density of active sites and relatively poor conductivity of 2H-MoS 2 lead to limited photocatalytic activity [ 19 , 20 ].…”