Investigation of Rhenium‐Doped MoS₂ Nanoparticles with Fullerene‐Like Structure

Abstract

The synthesis of rhenium‐doped fullerene‐like MoS2 nanoparticles (Re:IF‐MoS2) is described. Careful inductively coupled plasma mass spectrometry analysis reveals that the concentration of the rhenium atoms in the IF‐MoS2 lattice is more than 10‐fold smaller than the weighted amount of this atom in the precursor powder. High resolution scanning transmission electron microscopy in high angle annular dark field mode is used to decipher the isolated rhenium atoms in the MoS2 lattice and confirm that these atoms substitute for molybdenum atoms. Scanning electron microscopy analysis shows that, in contrast to the undoped nanoparticles which tend to agglomerate, the Re:IF‐MoS2 nanoparticles self‐assemble on substrate surfaces forming an ordered tessellated monolayer. Theoretical quantum‐chemical calculations show that the Re level is some 180 meV below the conduction band. Furthermore, the rhenium electrons are fairly localized in the MoS2 lattice. At a higher concentration the rhenium atoms form a mini‐band below the conduction band which coincides with the Fermi level of the lattice.

Interaction Between Selected MoS2 Nanoparticles and ZDDP Tribofilms

“…This is not surprising as ZDDP forms thick tribofilms that prevent 7,9) surfaces from wearing. It is interesting to note that all three nanoparticles investigated in this study showed lower disc wear than PAO with ZDDP.…”

“…The concentration of Re in the Re/IF-MoS 2 is about 100 ppm (0.01 at.%). A detailed description about the synthesis can be found elsewhere [9]. The size of the IF-MoS 2 is approximately 120-130 nm (mean value) in diameter.…”

“…For the synthesis of Re/IF-MoS 2, the fundamental reaction parameters were slightly modified from those employed in Ref. [8], and the Re x Mo -x O 3 (x \ 0.01) precursor powder was prepared in a specially designed auxiliary reactor [9,12]. The concentration of Re in the Re/IF-MoS 2 is about 100 ppm (0.01 at.%).…”

“…The IF-NPs were synthesised by quartz reactor using MO 3 powder as precursor and H 2 S/H 2 gas at a temperature of 800-830°C, and a final annealing step at 870°C, according to the procedure published in Ref. [8,9,12]. For the synthesis of Re/IF-MoS 2, the fundamental reaction parameters were slightly modified from those employed in Ref.…”

“…However, it appears that the above-mentioned mechanisms were derived based on experiments with model fluids [6][7][8][9][10][11][12][13][14][15][16] or on tests under dry contact conditions, mostly on steel surfaces. Some recent studies have explored the potentials of nanoparticles with non-ferrous surfaces such as diamond-like carbon (DLC) coatings [10,11].…”