The tuning of pore structures and acidity for Zn/Al layered double hydroxides: The application on selective hydrodesulfurization for FCC gasoline

Co–Mo catalysts applied on the hydrodesulfurization (HDS) for FCC gasoline were prepared with Zn–Al layered double hydroxides (LDHs) to improve their performances, and the effects of pore structures and acidity on HDS performances were studied in detail. A series of Zn–Al/LDHs samples with different pore structures and acidities are synthesized on the bases of co-precipitation of OH−, CO2−, Al3+, and Zn2+. The neutralization pH is a main factor to affect the pore structures and acidity of Zn–Al/LDHs, and a series of Zn–Al/LDHs with different pore structures and acidities are obtained. Based on the representative samples with different specific surface areas (SBET) and acidities, three CoMo/LDHs catalysts were prepared, and their HDS performances were compared with traditional CoMo/Al2O3 catalysts. The results indicated that catalysts prepared with high SBET possessed high HDS activity, and Brönsted acid sites could reduce the thiol content in the product to some extent. All the three catalysts prepared with LDHs displayed little lower HDS activity but higher selectivity than CoMo/Al2O3, and could restrain the reactions of re-combination between olefin and H2S which could be due to the existence of Brönsted acid sites.

The Zn/Al hydrotalcites with different pore structures and acidities are synthesized by co-precipitation. The hydrotalcites supported CoMo catalyst exhibited a balanced performances applied on hydrodesulfurization of FCC gasoline.Figure optionsDownload as PowerPoint slide