One step synthesis and characterization of CdS nanorod/graphene nanosheet composite
Highlights
► CdS nanorod/graphene nanosheet nanocomposite was synthesized by one-step pyrolysis process. ► Well-dispersed and coated CdS nanorods were obtained by acid treatment method. ► The acid-treated nanocomposite presented remarkable fluorescence quenching effect.
Introduction
Low-dimensional nanostructures are ideal systems for exploring a large number of novel phenomena at the nanoscale and investigating the size and dimensionality dependence of their properties for potential applications [1], [2], [3], [4], [5], [6], [7]. For example, the uniqueness of graphene nanosheets (GNS) in the high-efficiency of energy conversion makes it a new favourite among composite materials [8], [9], [10], [11], [12], [13], [14], [15]. Much effort has been made to functionalize graphene nanosheets, which leads to a broad new class of graphene-based materials and their various applications, such as the integrations of GNS with metal, semiconductor or polymer for the creation of energy storage materials [16], new biosensors [17] and fuel cells [18]. Among them, the incorporation between semiconductor and GNS is of paramount importance in the designing of energy conversion devices. Thus the incorporation technique is intensely focused by many material scientists. In general, two preliminary steps are adopted to synthesize the GNS-based composites: the first step is to prepare GNS and another candidate component, respectively; and the second is to incorporate them into an anticipant nanocomposite. It is the most important issue to obtain large-scale graphene sheets. At present, there are mainly three different techniques to prepare GNS: (i) micromechanical cleavage [19], producing GNS in very limited quantity (ii) epitaxial growth of GNS on special substrate [20], requiring higher reactive temperature (>950 °C) and (iii) chemical reduction of exfoliated graphite oxide suspension [21], demanding strong reducing agent. The process of chemical functionalization of graphene has been achieved in liquid phase using different soluble substances [13]. Although there were some reports on the integration of CdS and graphene [13], [22], few of them were on the preparation of CdS nanorod/graphene nanosheet (CdS/GNS) nanocomposite using a single precursor in solid phase.
In this work, an organometallic pyrolysis approach has been improved to prepare the title composite. There are several benefits motivated us to adopt the method. Firstly, an appropriate organometallic complex of bis(2-mercaptobenzothiazolato)-cadmium(II) was selected as the single precursor, which can afford Cd, S and C elements simultaneously. Secondly, this operation procedure is a facile routine, only comprised of pyrolysis and acid treatment processes to obtain well-dispersed CdS nanorods coated by GNS. Thirdly, this method does not require any strong organic reducing agents usually used in the chemical reduction techniques of exfoliated graphite oxide suspension [21]. Lastly, the reaction successfully produces GNS in the lower temperature comparing with the preparation condition of epitaxial growth on special substrate [23].
Herein, we demonstrate an one-step method to synthesize CdS/GNS nanocomposite directly from the conventional pyrolysis of bis(2-mercaptobenzothiazolato)-cadmium(II) (Cd(C7H4NS2)2). And, the well-dispersed CdS/GNS were obtained by acid treatment process. The nanocomposite shows obvious quantum confinement and fluorescence quenching effects.
Section snippets
Preparation of Cd(C7H4NS2)2 (Cd(MBT)2)
All the chemicals and reagents were of analytical purity and used without further purifications. Cd(MBT)2 was prepared by the methods described in a previous paper [24]. A solution of Cd(NO3)2 (5 mmol) in 30 ml ethanol was added to a solution of 2-mercaptobenzothiazole (10 mmol) in about 50 ml ethanol, in which a ivory complex began to precipitate. After stirred for an hour, the precipitate was centrifuged, washed repeatedly with ethanol and deionized water, and dried overnight at 50 °C in an
Results and discussion
XRD measurement was performed to probe the structure and phase purity of the CdS/GNS composite. As shown in Fig. 1a, the XRD peaks of CdS in the graphene-based composite could be well indexed to hexagonal CdS (space group: P63mc, a = 4.136 Å, c = 6.713 Å, α = β = 90°, γ = 120° and JCPDS No. 06-0314). Compared with the strong peaks of CdS, the peaks of graphene were too weak to be observed in Fig. 1a. Fig. 1b is the Bragg peaks of the acid-treated sample, which exhibited peaks at almost the same place as
Conclusions
In conclusion, we report an effective approach to synthesize the CdS/graphene nanosheet composite using Cd(MBT)2 as a single precursor via pyrolysis in solid phase. TEM observation showed that CdS nanorods were coated by graphene nanosheets. XRD and XPS results showed that there was an interaction between CdS nanorods and GNS. The fluorescence spectrum of the primal product presented an evident quantum confinement effect compared with that of the pristine CdS. The fluorescence quenching of the
Acknowledgements
This project is supported financially by the Natural Science Foundation of China (grant no. 20974045) and the Natural Science Foundation of Jiangsu Province (no. BK2009385).
References (36)
- et al.
Prog. Mater. Sci.
(2011) - et al.
Appl. Surf. Sci.
(2011) - et al.
Appl. Surf. Sci.
(2011) - et al.
Carbon
(2007) - et al.
Solid Films
(2008) - et al.
Chem. Phys. Lett.
(2010) - et al.
Appl. Surf. Sci.
(2011) - et al.
Adv. Funct. Mater.
(2005) - et al.
Adv. Mater.
(2011) - et al.
J. Mater. Sci. Technol.
(2008)
Crit. Rev. Solid State Mater. Sci.
Adv. Mater.
J. Mater. Sci. Technol.
ACS Nano
J. Phys. Chem. C
Langmuir
J. Am. Chem. Soc.
ACS Nano
Cited by (33)
Two dimensional porphyrin-based metal–organic framework constructed on K<inf>4</inf>Nb<inf>6</inf>O<inf>17</inf> microflowers for highly efficient charge transfer and photocatalytic hydrogen generation
2022, Applied Surface ScienceCitation Excerpt :After the introduction of the CPMOF, these peaks disappear. Raman spectrum is commonly used to detect the information on the surface of the materials [30]. The disappearance of Nb-O peaks and interpolyhedral bending can be attributed to the following reasons, the coating and strong interaction (confirmed by Fig. 1b and Fig. 2) of two-dimensional CPMOF (without Raman activity, Fig. 4A (c)) on the K4Nb6O17 microsphere as well as the fluorescence effect of the attached CPMOF [31].
Novel GQD-PVP-CdS composite with enhanced visible-light-driven photocatalytic properties
2016, Applied Surface ScienceRemoval of hydrogen sulfide at ambient conditions on cadmium/GO-based composite adsorbents
2015, Journal of Colloid and Interface ScienceEffect of pH on the synthesis and characteristics of RGO-CdS nanocomposites
2014, Applied Surface ScienceCitation Excerpt :In Fig. 7(c) and (d), the peaks related to Cd (3d5/2 at ≈404 eV) and S (2p at 163.5 eV) are also present, shifted slightly from the actual values (405 and 165 eV, respectively) but still consistent with the values reported in the literature for CdS [29]. Both for Cd and S, the RGO–CdS nanocomposites prepared at higher pH exhibited higher high intensity, an indication that there is more CdS present at this pH. There was also some peak shift among the RGO–CdS materials prepared at different pH. A possible reason for this was that the Cd atoms accumulated electrons from RGO, which caused the electron density around the Cd atoms to increase and lowered the bonding energy between Cd and S [29]. Photocatalytic reduction of Cr(VI) by the RGO–CdS nanocomposites and pure CdS (prepared at pH 11) was performed under visible light irradiation.
Photocatalytic properties under visible light with graphene based platinium selenide nanocomposites synthesized by microwave assisted method
2014, Materials Science in Semiconductor Processing