Ligand tailoring metal–support interactions toward highly dispersed Ni/beta catalysts for n-hexane hydroisomerization

Abstract

Ni-based catalysts play a central role in the modern chemical industry but often exhibit poor metal dispersion, especially under high metal loadings. Tailoring metal–support interactions is crucial for improving dispersion and optimizing structural properties. Herein, using a solid-state ligand assistance strategy, we modulate Ni-complex structures by tailoring coordinating atoms and purposefully prepare highly dispersed Ni/beta catalysts under a Ni loading of 6 wt%, while elucidating ligand-mediated regulation of metal–support interactions. Advanced experiments reveal that the ligand assistance not only exerts steric hindrance effects but also enhances metal–support interactions, enabling the targeted construction of highly dispersed Ni clusters. This efficient synergy depends on the coordination structure of metal complexes and the interaction between coordinating atoms and surface groups of supports. Notably, amine-based ligands enable high coordination stability of Ni-complexes and strong interactions with beta zeolites, thereby facilitating Ni dispersion. This facilitates efficient synergy between metal and acid sites, thereby achieving superior conversion, isomer selectivity and di-branched isomer selectivity in n-hexane hydroisomerization. In contrast, while carboxyl- and hydroxyl-based ligands effectively stabilize Ni complexes, their weaker interactions with beta zeolites compromise Ni dispersion. This limited dispersion reduces active site accessibility, impairing metal–acid synergy and ultimately reducing both conversion and isomer selectivity. These results advance the rational design of highly dispersed Ni-based catalysts at high loadings.