Structure of intrazeolite molybdenum oxide clusters and their catalysis of the oxidation of ethyl alcohol

Novel Molecular Approaches to the Structure–Activity Relationships and Unique Characterizations of Co–Mo Sulfide Hydrodesulfurization Catalysts for the Production of Ultraclean Fuels

“…80 These results suggest that the HYD of butadiene occurs only on the Co sites of the CoMo binary sulfide catalyst at Co/Mo atomic ratio ²1 and that the Co sites play crucial roles in the HDS and HYD reactions. In agreement with the catalytic results, the FTIR spectra in Figure 14 of NO adsorption on CoSMoS 2 /NaY(Co/Mo = 1) 84,109 show that NO molecules are adsorbed exclusively on Co sites (1807 and 1867 cm ¹1 vs. 1660 and 1795 cm ¹1 for MoS 2 /NaY), forming dinitrosyl species, in spite of the presence of the equal amounts of Co and Mo atoms in the zeolite cavities (2Co + 2Mo atoms/ SC). These findings distinctly demonstrate the formation of CoMo mixed sulfides in the zeolite pores rather than a physical mixture of highly dispersed Co and Mo sulfide clusters.…”

“…84,109 The Co2p 3/2 BE for CoS/NaY was 778.5 eV in agreement with that for Co 9 S 8 (778.4 eV). However, CoSMoS 2 /NaY exhibited a Co2p 3/2 level at 779.3 eV, which is higher by 0.9 eV than that for CoS/NaY or Co 9 S 8 , indicating the formation of novel Co Taking into consideration the Mo content of 2Mo/SC and Co/Mo = 1, highly dispersed CoMo binary sulfide clusters, possibly Co 2 Mo 2 S x in the supercages of the NaY zeolite, may act as the catalytically active species.…”

“…84 The thiophene HDS activity increases with increasing Co/Mo atomic ratio to about unity, but decreases with further addition of Co. The observed activity of the mixed sulfide catalyst is considerably larger than the simple sum of the activities of the separate metal sulfide catalysts, indicating the generation of a catalytic synergy between the Co and Mo sulfides encaged in the zeolite cavities, as observed for conventional CoMo sulfide catalysts.…”

“…79,84 The activity of MoS 2 /NaY linearly increased up to 2Mo/SC as the Mo loading increased, followed by a more gradual increase with further addition of Mo. 79,84 This suggests that Mo sulfide dinuclear species with the same structure are prepared using [Mo(CO) 6 , respectively, as precursors. 94 The benzothiophene HDS activity was found to be significantly affected by the zeolite structure.…”

“…80, 84 As illustrated in Figure 13, the relative activity HYD/HDS or catalyst selectivity of MoS 2 /NaY thus considerably decreases on the addition of Co and reaches that of CoS/NaY at Co/Mo = 1. In addition, the selectivity of the butadiene HYD shifted from trans-but-2-ene-rich to but-1-ene-rich compositions with the addition of Co and became close to that on CoS/NaY at Co/ Mo = 1.…”