Double‐Volcano Catalytic Response in Furfural Reductive Amination Over Inverse Ni─Al Catalysts

Reductive amination of aldehydes and ketones to primary amines is an important route for biomass valorization, yet achieving efficient synergy between substrate and hydrogen activation in cascade reactions remains challenging. Herein, we construct a compositionally tunable Ni─Al catalyst system whose architecture evolves from conventional Ni/Al 2 O 3 to inverse Al 2 O 3 /Ni. This structural evolution gives rise to an unusual double‐volcano catalytic behavior in furfural reductive amination. Two activity maxima are identified over 30Ni/Al 2 O 3 and inverse Al 2 O 3 /90Ni, respectively, with the optimal Al 2 O 3 /90Ni catalyst delivering 98.5% furfurylamine yield and a space‐time yield of 65 mmol g cat −1 h −1 under mild conditions. Adsorption studies, initial‐rate kinetic isotope effect and reaction‐order measurements, apparent activation‐energy analysis, and in situ infrared spectroscopy indicate that the double‐volcano behavior reflects the coupled evolution of catalyst composition and architecture and a composition‐dependent balance between Lewis‐acid‐assisted intermediate formation and hydrogen‐dependent intermediate conversion. Hydrogen‐dependent steps exert a stronger kinetic influence over 30Ni/Al 2 O 3 than over Al 2 O 3 /90Ni, while the inverse catalyst exhibits enhanced H 2 adsorption and activation and more rapid Schiff base conversion. These results indicate a shift in the dominant kinetic limitation between the two catalysts and provide a framework for designing efficient non‐noble‐metal catalysts for multifunctional cascade reactions involving coupled substrate and hydrogen activation.