Structure Modification Of MoS2 Through Preparation Condition Management

Afify, H. H.; Obaida, M.; Swelam, Mai N.; Hassan, S.A.; Hashem, H. M.; ِِAbd El-Mongy, A.

doi:10.21608/ejchem.2022.124371.5540

Structure Modification Of MoS2 Through Preparation Condition Management

Document Type : Original Article

Authors

¹ Solid State Physics Department, Physics Research Institute, National Research Centre, 33 El Buhouth St., Dokki, 12622 Giza, Egypt

² Physics Department, Faculty of Science, Helwan University, Cairo, Egypt

10.21608/ejchem.2022.124371.5540

Abstract

One pot simple and easy procedure hydrothermal technique is used for MoS2 powder preparation. The structure of the final product 2D MoS2 is modified through preparation conditions modulation. The precursor solution pH is varied in the acidic side from 1 up to 5. The reaction temperature and time in the autoclave are kept constant while the pH is varied. The change in pH is studied at each of two reaction temperatures 210oC & 230oC and each one of three reaction times 24, 48, 72 hours. Crystal structure and phase identification are elucidated by XRD measurements. Morphology, shape, and size of fine structures are demonstrated by SEM & HRTEM images. As well surface area, elemental analysis, and oxidation state of elements are explored by BET, EDS, and XPS measuring techniques. XRD patterns peaks of the investigated sample are indexed with JCPD standard files and found to be well matched with that of the 2H-MoS2 phase of the MoS2 product. Also, the crystallite size is calculated by Appling SHERER equation on the well-defined and high intensity peak in the XRD pattern. XRD patterns show that at both low reaction time and temperature the end product is almost amorphous at pH 1&3 while at 4&5 it is polycrystalline. SEM images show a flower-like structure composed of spheres of nanosheets. HRTEM images demonstrate more details about the present fine structures such as nanosheet spheres and their arrangement. As well SAED patterns identified the amorphous and crystalline state combined with the nomination of planes. Also, the arrangement of nanosheets and the distance between layers in the bundle are determined. The surface area of MoS2 constituents is measured by BET method. The obtained results show that samples with (001) plane have a value of 59m2/g while that containing (002) plane have a value of 19m2/g. The elemental analysis measured by EDS displays the existed elements S & Mo with their percentage. The ratio of Mo/S is found to be nearly ½. The existed elements of the MoS2 product are confirmed by XPS measurements. The oxidation states of the elements are determined from Mo & S peaks and their deconvolution.

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