Catalysis by sulfides: Advanced IR/CO spectroscopy for the identification of the most active sites in hydrodesulfurization reactions

• Advanced IR/CO distinguishes (Co)MoS sites based on promotion degree and edge location. Sulfide are characterized by the IR frequency affinity of adsorbed CO. Absence unpromoted S-edge CoMo catalyst series is revealed. The 3 different CoMoS have intrinsic HDS activity. Partially promoted M- more active than totally sites. Sulfided supported TiO 2 , Al O or SiO was studied CO adsorption followed infrared spectroscopy (IR/CO). inversion isotherms obtained (the 2D-IRIS method) performed nonpromoted catalysts to verify that ν(CO) vibration contributions from 2090 2000 cm −1 can be attributed CO/CoMoS interactions, free contribution coming CO/nonpromoted S-edges MoS nanoparticles. second derivative spectra evidences presence three Promotion in situ chemical vapor deposition makes it possible ascribe ν(CO/CoMoS) partially M-edges (2072–2074 2082–2085 ) (2054–2057 ). Then method highlights Co both edges M-edge) slabs. hydrodesulfurization activity these shows total concentration an important but not unique factor, since structures modify their A parallel with site amounts reveals M-edge CoMo-supported most for hydrodesulfurization. This a direct way account types catalysts.