Metal-dependent gadolinium interfacial regulation of Pt/Y and Ni/Y zeolite catalysts for highly selective and durable jet-fuel production via hydroprocessing

Gd regulates metal–zeolite interfaces in bifunctional Y zeolite catalysts. • Sequential Gd introduction improves Pt dispersion and suppresses over-cracking. • Gd co-impregnation stabilizes interfacial Ni 2+ species in Ni/Y catalysts. • Ni–Gd/Y lowers the jet-fuel productivity deactivation rate by 7.7-fold. • Optimal Gd loading widens the C 8 –C 15 operating window in Pt–Ni/Y catalysts. Selective hydroprocessing of long-chain paraffins to jet-fuel-range hydrocarbons (C 8 –C 15 ) requires bifunctional catalysts that combine high selectivity with long-term durability. Here, we show that gadolinium (Gd) acts as an interfacial regulator whose effects on zeolite Y-supported Pt and Ni catalysts are metal- and preparation-dependent. In the Pt/Y system, sequential Gd introduction improves Pt nanoparticle dispersion, increases the surface metallic fraction, and shifts the acid balance toward a more Brønsted-weighted environment, collectively widening the isomerization window and shifting the yield optimum to a lower extent of cracking, which raises the maximum C 8 –C 15 yield from 45.7 to 52.4 wt% in n-hexadecane hydroprocessing. In the Ni/Y system, Gd instead stabilizes interfacial oxidized Ni 2+ species and attenuates the accessible acid site population; although the conversion onset shifts to higher temperature, the jet-fuel productivity deactivation rate constant decreases by approximately 7.7-fold (1.10 × 10 −2  → 1.43 × 10 −3  h −1 ) over 100 h on stream, driven by suppressed Ni sintering and reduced carbonaceous deposition (16.3 → 9.6 wt%). These metal-dependent effects transfer to Pt Ni bimetallic catalysts, where Gd loading produces a volcano-type dependence of the jet-fuel operating window (ΔT 50 ), with 0.5Pt–(10Ni3Gd)/Y delivering the optimum balance between selectivity and high-temperature robustness. These results establish rare-earth-enabled interfacial engineering as a generalizable strategy for simultaneously tuning selectivity and durability in bifunctional zeolite catalysts for aviation fuel production. Download: Download high-res image (149KB) Download: Download full-size image