Preparation and Characterization of γ-Al2O3 with Rich Brønsted Acid Sites and Its Application in the Fluid Catalytic Cracking Process

The objective of this work is to investigate the surface acidity of γ-Al2O3 after modification and its application in reducing coke formation in the fluid catalytic cracking (FCC) process. γ-Al2O3 with rich Bronsted acid sites and reduced Lewis acid sites was prepared by the sol–gel method using NH4BF4 as a modifier to develop a new functional material to adjust surface acidity. N2 sorption, powder X-ray diffraction (XRD), 27Al magic angle spinning nuclear magnetic resonance (27Al MAS NMR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR) spectroscopy were used to characterize the structure and surface properties of the prepared γ-Al2O3. The results showed that partial fluorination of the surface of γ-Al2O3 generated small quantities of a pyrochlore-type phase which was formed mainly by substitution of the OH group on six-coordinated aluminum with fluorine. In addition, boron insertion in the structure of γ-Al2O3 reduced the Lewis acid concentration and increased...