Highly active spherical amorphous MoS₂: facile synthesis and application in photocatalytic degradation of rose bengal dye and hydrogenation of nitroarenes

Abstract

Herein, we developed a facile method to prepare an amorphous spherical MoS 2 21 via a simple solvothermal decomposition of a precursor complex MoO 2 (acda) 2 (Hacda = 2-22 33 Keywords: Amorphous MoS 2 , rose bengal, visible light photocatalyst, nitro compounds, 34 hydrogenation, heterogeneous catalyst 35 36 37 38 39 40 41 42 45different natural products, the reduction of p-nitrophenol 1-9 has drawn extensive attention in 46 recent years. Silver, gold, platinum and palladium metal NPs or metal nanocomposites [10][11][12] 47 are known to be typical catalysts applied in the catalytic hydrogenation of p-nitrophenol. 48Although the catalytic performances of these catalysts are relatively satisfactory, there is a 49 need to limit the use of such very expensive catalysts. It is thus desirable to move away from 50 rare elements and catalyze the reaction through cheap, earth-abundant materials. This 51 challenge has led to the exploration of molybdenum sulfides as catalysts for the 52 hydrogenation of p-nitrophenol. Moreover, preparation of MoS 2 are of considerable attention 53 for its potential applications in many areas as catalysis, 13 potential hydrogen storage media, 14 54 electrode materials for Mg 2+ ion and Li + ion batteries, 15,16 solid super lubricants, 17,18 55 superconductors, 19,20 and photo-electrochemical solar cells, 21,22 hydrogen evolution reaction. 56In contrast no such reports are concerned on the catalytic behaviour of amorphous MoS 2 for 57 the decomposition of organic pollutants like dyes 23-29 and for the catalytic reduction of nitro 58 groups to amino groups. Now a days, the synthesis of amorphous MoS 2 is a great challenge 59 due to its high performances mainly due to high surface area and large concentration of 60 lattice defects in the amorphous structures. Therefore a simple, cost-effective method for the 61 synthesis of amorphous MoS 2 is essential to explore the different catalytic activities. Despite 62 all other various solution-phase synthetic strategies, the thermo decomposition of a single-63 source precursor (SSP) method may be useful, since it has been proven facile and valid in 64 obtaining a variety of metal chalcogenide NPs with the characteristics of single crystallites, 65 pure phases, definite stoichiometries and monodispersities. O'Brien pioneered this facile 66 synthetic process and first obtained different chalcogenides 30-33 viz. sulphides and selinides 67 The ligand, 2-aminocyclopentene-1-dithiocarboxylic acid (Hacda) has already been 88 synthesized according to the previously reported method. 38 The precursor complex, 89 MoO 2 (acda) 2 was prepared according to the prescribed method. 39 90 91 The synthesis of amorphous MoS 2 was carried out through a solvothermal 93 decomposition of synthesized precursor complex using nucleophilic solvent TETA. The 94 precursor complex MoO 2 (acda) 2 (200mg) was dissolved in 4 mL TETA and transferred into a 95 10 mL round bottom flask. The reaction mixture was then heated for 1.5 hr at 200˚C in an 96 inert atmosphere. The black particles...

Noble metal-coated MoS2 nanofilms with vertically-aligned 2D layers for visible light-driven photocatalytic degradation of emerging water contaminants

“…3(a) inset). The band gap (E g ) of the sample was estimated by using the Tauc’s equation, ( α(ν)*hν ) 1/n = A ( hν − E g ), where α(ν) , A , n are the absorption coefficient, proportionality constant, and gap-type depending exponent, respectively 31 , 32 . In this case, n = 2 is assigned such that multi-layered MoS 2 presents indirect band gap originating from the maximum of valence band at Γ and the minimum of conduction band halfway between Γ and K 33 .…”

Morphology-controlled MoS2 by low-temperature atomic layer deposition

“…50 The disappearance of distinguished A and B excitonic peaks (∼600-700 nm) may be due to the amorphous or poor crystallinity of MoS 2 deposited and annealed at low temperatures. 51,52 The appearance of a prominent peak around 410 nm also reflects the simultaneous existence of few-layer and nanocrystals. 53 With the increase of the number of ALD cycles the absorption intensity increased significantly, which reflects the increase of mass loading of MoS 2 .…”

Formation of Hierarchical 2D-Mos2 Nanostructures over Carbon Fabric as Binder Free Electrode Material for Supercapacitor Applications

“…The diffraction peaks correspond to (002), (100), (101), (103), and (105) reflections, signified the nanostructured 2H-MoS 2 (JCPDS 37-1492) [18]. And the diffraction peaks which correspond to (004), (101) indicated the nanostructured 3R-MoS 2 (JCPDS 17-0744) [19]. Figure 3(a), it is clearly seen that the carbon fabrics are compactly packed with random orientation in order to form a macroporous open structure [20,21].…”