Bidirectional Adsorption Modulation over PtNi Alloy Enables Selective Hydrogen-Borrowing Amination to Primary Amines

Primary amines serve as essential building blocks in fine chemical synthesis. Hydrogen-borrowing amination of alcohols represents an atom-economical strategy for amine synthesis, yet its application faces challenges due to high reaction temperatures and low selectivity toward primary amines. Herein, we report a PtNi/CeO2 alloy catalyst that achieves exclusive production of primary amines (100% selectivity among N-contained compounds) under mild conditions (120 °C), significantly outperforming state-of-the-art catalysts. Comprehensive characterizations (AC-HAADF-STEM, XAS, and CO-FTIR) unambiguously verify the formation of the PtNi alloy structure. Mechanistic investigations and DFT calculations reveal that electronic synergy within the PtNi alloy induces charge redistribution (electron transfer from Ni to Pt), which enhances NH3 chemisorption while weakening primary amine adsorption. This synergistic modulation establishes a self-regulated dynamic equilibrium system: (i) facilitating the rapid condensation of in situ generated carbonyl intermediates with surface-concentrated NH3 to favor primary amine formation; (ii) enabling instantaneous primary amine desorption, thereby suppressing the formation of undesired Schiff bases and secondary amines. This work provides a paradigm for the selective construction of C–N bonds via bidirectional modulation in hydrogen-borrowing amination. Furthermore, the catalyst demonstrates direct applicability in converting lignin-derived C8–C9 alcohols and poly(propylene oxide) (PPO) plastic into valuable nitrogen-containing compounds with yields exceeding 90%.