Highly Active and Air-Stable Iron Phosphide Catalyst for Reductive Amination of Carbonyl Compounds Enabled by Metal-Support Synergy.

Iron has long been recognized as an ideal catalytic material for sustainable chemistry. However, conventional iron catalysts employed in liquid-phase hydrogenation reactions suffer from poor activity and air instability, severely restricting their wide applicability in practical use. Herein, we present the development of highly active and air-stable iron phosphide nanocrystal immobilized on zirconia (Fe2P NC/ZrO2) for the reductive amination of aldehydes and ketones. The Fe2P NC/ZrO2 catalyst demonstrated broad substrate applicability, high recyclability, and scalability in both gram-scale and continuous-flow processes. This catalyst leverages the synergistic metal-support effect of Fe2P NCs and ZrO2 support, leading to activity 313 times higher than that of conventional iron nanoparticle catalysts. In-depth mechanistic studies elucidated that the distinctive interplay between Fe2P and ZrO2 significantly accelerates ammonolysis of Schiff bases, a key step for boosting reaction efficiency. This study sets a new benchmark for iron-based catalysis, offering a robust alternative to precious metals, thereby contributing significantly to sustainable chemical manufacturing and green organic synthesis.