Construction of Hierarchical Core-Shell Pt/USY@MSA Bifunctional Catalysts for Hydroisomerization of N-Hexadecane

Hydroisomerization of long-chain n-alkanes is an indispensable process in the upgrading of fuel oil and lubricants to meet the state of art regulations. In this work, a novel core-shell structural material comprising USY zeolite core and mesoporous aluminosilicate (MSA) shell, denoted as USY@MSA, was fabricated by virtue of a desilication and recrystallization approach. Comprehensive characterizations demonstrate that the USY@MSA composite exhibits a hierarchical pore architecture and a gradient acidity. Due to the confinement effect of the mesoporous aluminosilicate shell, highly dispersed platinum particles were selectively deposited on the shell, generating a nanoscale distance with acidic sites of USY zeolite core. In the hydroisomerization of n-hexadecane, the Pt/USY@MSA composite catalyst outperforms the conventional Pt/USY and desilicated Pt/USY-ds catalysts, effectively suppressing the cracking side reactions and producing higher selectivity to branched isomers.