N-octyltrimethylammonium bromide-assisted self-assembly of CoMo precursors to prepare CoMoS/Al2O3 catalysts for highly selective hydrodesulfurization of thiophene

A novel (C 11 H 26 N) 2 Co(MoS 4 ) 2 complex was prepared via the n-octyltrimethylammonium bromide-assisted self-assembly of CoMo precursors for the selective hydrodesulfurization (HDS) of thiophene. The complex was generated by the interaction between the negatively charged CoMo compound and the positively charged n-octyltrimethylammonium ions. Then positively charged bimolecular layers were formed owing to van der Waals forces between the C 11 H 26 N + and the complex, and they were anchored on the negatively charged γ-Al 2 O 3 . Compared with CoMoS/γ-Al 2 O 3 catalysts prepared by impregnation, the optimal CoMoN-0.3/γ-Al 2 O 3 catalyst exhibited better performance for selective HDS due to the enhanced Mo dispersion, the close contact between Co and Mo, and the increased amount of CoMoS phases on γ-Al 2 O 3 . Among these catalysts, the optimal CoMoN-0.3/γ-Al 2 O 3 catalyst with the highest concentration of CoMoS phases exhibited the highest HDS reaction rate constant of 6.95 × 10 -6 mol·g −1 ·s −1 and the best selective factor of 26.1 for the selective HDS of thiophene with 1-hexene.