Insight into metal-support synergistic effect from the perspective of increasing propylene production in catalytic cracking over Au/ZSM-5 catalysts

Propylene, as an important chemical basic raw material, is in increasing demand year by year. Au/ZSM-5 as a bifunctional catalyst exhibits excellent catalytic performance and propylene selectivity in low-temperature catalytic cracking to propylene reaction. The smaller Au size (5.8-8.2 nm) is prepared through deposition precipitation, but the characteristics of support will also undergo partial changes at the same time. The support characteristics have been confirmed to have changed through a series of characterizations. The propylene yield could reach 42% at 410 oC when the value of CH/CM is 40. A proposed metal-acid synergistic catalysis mechanism for octane catalytic cracking to produce propylene is elucidated. The higher propylene yield is attributed to the synergy between acid sites and Au species. Our research results provide a reasonable and effective correlation between the metal-acid activity of bifunctional catalysts and catalytic activity in catalytic cracking reactions to produce propylene.