Mechanochemistry Strategy in Metal/Fe₃O₄ with High Stability for Superior Chemoselective Catalysis

While noble metal nanoparticles (MNPs) exhibit remarkable performance in heterogeneous catalysis and their incorporation into crystalline materials can fully exploit the combined advantages of both, achieving introduction of nanoclusters during material crystallization, precisely controlling their interactions, and facilitating catalyst recovery remain significant challenges. In this study, Au NPs, Pt NPs, and Pd NPs are supported on magnetic Fe₃O₄, enabling the modulation of the electronic states of MNPs by adjusting the introduction method. Notably, the catalysts (Pt/Fe₃O₄, Au/Fe₃O₄, and Pd/Fe₃O₄) demonstrate excellent activity in chemoselective reactions: cinnamaldehyde (CAL) hydrogenation (turnover number: 20,135 h^-1), nitrobenzene hydrogenation (with 99.9% selectivity for major nitrobenzene derivatives and robust stability at 19 cycles), and 3-nitrophenylacetylene (3-NPA) hydrogenation (yielding up to 98.4% 3-aminophenylacetylene (3-APA)), in stark contrast to the low activity of comparable catalysts. This paper proposes a novel and versatile solid-phase mechanochemistry strategy that achieves precise control over the microenvironment of MNPs while maintaining their inherent activity, thereby offering an effective approach to develop catalysts with high specificity and easy recovery capabilities.