Enhancing selective hydrogenation of pyridine: The role of nickel doping in Pt/γ-Al2O3 catalysts

• The dispersion of Pt was improved, and its electronic properties were effectively regulated through Ni doping. • DFT calculations revealed that the desorption energy barrier of piperidine was reduced by Ni doping. • The hydrogenation selectivity was enhanced by Ni doping. • The highest activity was observed in catalyst Pt 3 Ni 1 /Al 2 O 3 catalyst. Highly dispersed PtNi bimetallic sites were constructed on γ-Al 2 O 3 through a nickel doping strategy for selective pyridine hydrogenation. Optimal Ni doping promoted active site exposure, optimized reactant diffusion pathways, and influenced pyridine adsorption via electronic microenvironment modulation. The Pt-Ni electronic synergy was maintained while suppressing C–N bond hydrogenolysis through surface adsorption barrier control. Density functional theory (DFT) calculations confirmed reduced piperidine desorption energy barriers due to Ni doping. Under continuous flow conditions (453 K, 3.5 MPa, H 2 /oil 500:1, LHSV 3 h −1 ), Pt 3 Ni 1 /Al 2 O 3 achieved 87.9 % pyridine conversion and 96 % piperidine selectivity. The enhanced performance originated from highly dispersed bimetallic sites, optimized acid distribution, and electronic synergy, providing a new idea for the selective hydrogenation of heterocyclic compounds.