Synthesis of MCM-41-HY Composite Molecular Sieves and Their Application to Deep Hydrodesulfurization

MCM-41-HY composite molecular sieves were synthesized hydrothermally, and characterized by means of XRD, N_2 adsorption and SEM. A comparison was made between the mechanical mixture of MCM-41 and HY, and the synthesized MCM-41-HY composite molecular sieves as the hydrodesulfurization(HDS) catalyst support. Both exhibit excellent activities in the HDS hydrodesulfurization of dibenzothiophene, but, the composite shows a much lower hydrocracking activity than the mechanical mixture. It is proposed that the lower hydrocracking activity of MCM-41-HY composite molecular sieves may be attributed to the bimodal structure in which HY zeolite is wrapped by the mesoporous MCM-41.