Insight into metal-support interactions from the hydrodesulfurization of dibenzothiophene over Pd catalysts supported on UiO-66 and its amino-functionalized analogues

Abstract

The hydrodesulfurization (HDS) of dibenzothiophene (DBT) was studied over a series of Pd catalysts supported on Zr-based metal-organic frameworks, UiO-66 and its amino-functionalized analogues (UiO-66-xNH2, where x represents the molar ratio of 2-amino-1,4-benzenedicarboxylic acid/1,4-benzenedicarboxylic acid) to gain an insight into metal-support interactions. Pd/UiO-66 behaved better than a Pd/γ-Al2O3 catalyst and a Pd/MCM-41 catalyst. The presence of amino groups showed minor negative influence on the conversion of DBT but significantly affected the activities and selectivities of different reaction pathways. With the increase in the content of amino groups, the direct desulfurization (DDS) pathway activity of the Pd/UiO-66-xNH2 catalysts increased, while their hydrogenation pathway activity decreased. This provides an approach for the regulation of the pathway selectivities of Pd HDS catalysts. Based on kinetic analysis and characterization results, we propose that the amino groups affect the HDS performance of Pd/UiO-66 mainly by affecting the adsorption of reacting molecules on metal particles.