Improved photocatalytic activity of MoS₂ nanosheets decorated with SnO₂ nanoparticles

Abstract

MoS 2 nanosheet decorated with SnO 2 mesoporous nanoparticles were successfully prepared by a facile two-step method. MoS 2 nanosheets were pre-synthesized using a solvothermal method and then decorated with the SnO 2 mesoporous nanoparticles through a wet chemical method. The nanocomposite was characterized with powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersed spectrometry (EDX), high-resolution transmission electron microscopy (HRTEM), thermal gravimetric and differential thermal analysis (TG-DTA), X-ray photoelectron spectroscopy (XPS) andElectrochemcial impedance spectroscopy (EIS). SnO 2 mesoporous nanoparticles can be selectively formed and attached to the peripheral surface of the layered MoS 2 , which was confirmed by FESEM and HRTEM. The photocatalytic activity of the nanocomposite was examined with Rhodamine B (RhB) in aqueous solution under UV light irradiation. The SnO 2 nanoparticles remarkably suppressed the electron-hole recombination effect on the MoS 2 photocatalyst and improved photocatalytic activity compared to pristine MoS 2 catalyst. A higher rate of pollutant degradation was accomplished within 50 min that was three times higher than that of the pristine MoS 2 catalyst. the presence of CTAB. Photocatalysis experiments prove that this heterogeneously structured composite has higher photocatalytic activity than pristine MoS 2 . Experimental ProcedureAll chemicals were analytical grade and used as received without further purification. Preparation of MoS 2 nanosheetsTo obtain the MoS 2 nanosheets, ammonium hepta molybdate tetrahydrate, citric acid, and thiophene (C 4 H 4 S) were used as the starting materials and sulfur source. 2.05 g of ammonium heptamolybdate tetra hydrate and 1.56 g of citric acid were dissolved in distilled water and magnetically stirred for 10 min at 90˚C on a hot plate to form a homogeneous solution. The white suspension was vigorously stirred and the pH was adjusted to 3.5 with the addition of ammonia water. Then, 3.15 g of thiophene in water was added dropwise to the solution and transferred to an autoclave, which was maintained at 200˚C for 10 h. After natural cooling of the reactor down to 25˚C, the resulting precipitates were collected through centrifugation, filtered, and washed three times with distilled water and acetone. The final precipitates were dried under vacuum at 130˚C for 2 h. Preparation of MoS 2 sheets decorated with SnO 2 nanoparticlesThe MoS 2 precipitates (20 mg) were exfoliated in distilled water (25 mL) and heated at 75˚C under magnetic stirring for 30 min to form a colloidal suspension. Then, SnCl 2 •2H 2 O (2.7 g) was dissolved in the colloidal solution. HCl (1.3 mL) and H 2 O (30 mL) were added drop-wise to the solution with continuous heating and stirring for 2 h. After several trials, we optimized the concentration of CTAB to 0.05 mmol. 0.05 mmol of CTAB was added to the suspension and stirred at 110˚C for 6 h. The final products were collected, filtered, and washed three times with acetone...

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

“…As shown in Figure e, the intervention of a highly conductive nanosheet prevents the electron–hole recombination because this nanosheet attracts photogenerated charge species from the surrounding material by acting as a charge reservoir. As depicted in Figure f, the narrow‐bandgap semiconducting component can function as a light sensitizer in this hybrid system, even if it is not photocatalytically active …”

Molybdenum Disulfide-Based Photocatalysis:Bulk-to-Single Layer Structure and Related Photomechansim for Environmental Applications

“…This composite structure showed a blue shift in absorbance due to quantum confinement of the charge carriers [28,45]. We recently reported improved photocatalytic performance of MoS 2 nanosheets decorated with mesoporous SnO 2 nanospheres by a facile two-step method [46]. We also observed the photocatalytic effect in the degradation of RhB with less than 50 min of UV light irradiation.…”

Recent advances in two‐dimensional transition metal dichalcogenides as photoelectrocatalyst for hydrogen evolution reaction

“…[112][113][114] Apart from TiO 2 , other metal oxides such as WO 3 , Fe 2 O 3 , ZnO, MoO 3 , SnO 2 , and Cu 2 O have also been considered. [115][116][117][118][119][120] For example, Yang and coworkers have reported a WO 3 /WS 2 composite as a catalyst with excellent kinetics toward the PEC-HER. 121,122 Moreover, 2D-TMDs can also be combined with other light absorbers such as CdS, CdSe, CdLa 2 S 4 , and graphitic carbon nitride (g-C 3 N 4 ) to form co-catalysts for the PEC-HER (Fig.…”