In situ raman investigation of hydrodesulphurization catalysts

Abstract

Raman spectra of a commercial Co-Mo/Al₂O₃ hydrodesulphurization catalyst were recorded in an H₂S/H₂ atmosphere at 400°C by means of a specially designed in-situ cell. For an improvement of the signal to noise ratio the incident laser beam was scanned over the surface of the sample by reflection from a rotating octagon. The spectra proof that the so called “Co-Mo-S” crystallites are present as an MoS₂-type layered material with an average particle size of each slab being larger than sometimes proposed up to now.