Application of pair distribution function analysis to structural investigation of alumina supported MoS2 catalysts

Total X-ray scattering and atomic pair distribution analysis (PDF) were used to study structure of anisotropic two-dimensional (2D) MoS2 nanoparticles in MoS2/Al2O3 catalysts. We demonstrated that PDF analysis can be used not only to determine the atomic ordering but also to assess the geometry and size of 2D MoS2 nanoparticles in the catalysts. In refinement of PDFs, discrete atomistic modeling was used to account for finite size and shape effects. The values of MoS2 slab length elucidated from the PDF data were smaller than values obtained from high-resolution transmission electron microscopy (HRTEM) data due to defectiveness and multi-domain structure of the MoS2 nanoparticles. It was suggested that increase in the temperature of heat treatment of oxide precursors leads to decrease in deformation of the MoS2 nanoparticles in sulfided catalysts.