Mechanochemistry\nStrategy in Metal/Fe<sub>3</sub>O<sub>4</sub> with High Stability\nfor Superior Chemoselective Catalysis

While noble metal nanoparticles (MNPs) exhibit remarkable\nperformance\nin heterogeneous catalysis and their incorporation into crystalline\nmaterials can fully exploit the combined advantages of both, achieving\nintroduction of nanoclusters during material crystallization, precisely\ncontrolling their interactions, and facilitating catalyst recovery\nremain significant challenges. In this study, Au NPs, Pt NPs, and\nPd NPs are supported on magnetic Fe<sub>3</sub>O<sub>4</sub>, enabling\nthe modulation of the electronic states of MNPs by adjusting the introduction\nmethod. Notably, the catalysts (Pt/Fe<sub>3</sub>O<sub>4</sub>, Au/Fe<sub>3</sub>O<sub>4</sub>, and Pd/Fe<sub>3</sub>O<sub>4</sub>) demonstrate\nexcellent activity in chemoselective reactions: cinnamaldehyde (CAL)\nhydrogenation (turnover number: 20,135 h<sup>–1</sup>), nitrobenzene\nhydrogenation (with 99.9% selectivity for major nitrobenzene derivatives\nand robust stability at 19 cycles), and 3-nitrophenylacetylene (3-NPA)\nhydrogenation (yielding up to 98.4% 3-aminophenylacetylene (3-APA)),\nin stark contrast to the low activity of comparable catalysts. This\npaper proposes a novel and versatile solid-phase mechanochemistry\nstrategy that achieves precise control over the microenvironment of\nMNPs while maintaining their inherent activity, thereby offering an\neffective approach to develop catalysts with high specificity and\neasy recovery capabilities.