Experimental and theoretical properties of S–Mo–Co–S clusters

In this work we propose that certain structures found in real commercial catalysts may be related to low dimensional structures. These structures are S–Mo–S and S–Mo–Co–S nanowires which were characterized by High Resolution Scanning Transmission Electron Microscopy (HR-STEM), Electron Diffraction (ED) and Electron Dispersive X-ray analysis (STEM-EDAX). Furthermore, a structural model was constructed with the one dimensional structures in order as to investigate their electronic properties. Energy band analysis on the samples yield indication about the semi metallic behavior, while a careful analysis to the partial Density of States (PDOS) in the vicinity of the Fermi level, provided indication for the existence of strong hybridization between S p- with Mo d- and Co d- and p-orbitals for the samples enunciated formerly. In addition, a very important issue to be mentioned is that in the construction of the 1T-S–Mo–Co–S nanowires, the Co and Mo atoms are not in their pure trigonal prismatic environment as compared to the bulk 2H-MoS2. This issue could be deleterious for future catalytic applications.

Graphical abstractOur research provides evidence for the existence of S–Mo–S, S–Mo–Co–S and S–Mo–Co–S with rotated planes nano wires. This evidence was proved by means of High Resolution Transmission Electron Microscopy as shown in the following figure. The S–Mo–S, S–Mo–Co–S and S–Mo–Co–S with rotated planes yielded semi metallic to the first two structures and metallic behavior to the last one..Figure optionsDownload full-size imageDownload high-quality image (133 K)Download as PowerPoint slideResearch highlights► MoS2 samples were prepared and characterized by High Resolution Transmission Microscopy. ► The samples showed existence of S–Mo–S, S–Mo–Co–S and S–Mo–Co–S with rotated planes. ► Theoretical analysis was performed on such structures showing semi metallic behavior. ► A hybridization was manifested for three structures under study. ► The nano wires are 1T-MoS2 configuration, the metal are not in a trigonal prismatic environment.