Boosting the Activity of Ligand-on Atomically Precise Pd3Cl Cluster Catalyst by Metal-Support Interaction from Kinetic and Thermodynamic Aspects

Atomically precise nanoclusters (APNCs), as ideal model catalysts, revealed great advantages to deep-understand of reaction mechanisms in heterogeneous catalysis. Boosting the activity of APNCs is the most critical issue under the premise of maintaining structure invariance. Herein, utilizing Metal-Support Interaction (MSI) strategy, we prepared an excellent and recyclable catalyst for aerobic oxidation by combination of an otherwise inert nanocluster [Pd3Cl(PPh2)(2)(PPh3)(3)](+)[SbF6](-) (denoted as Pd3Cl) with functional titanate nanotubes (TNT). The promising Pd3Cl/TNT composite gives rise to excellent conversion with 100% selectivity without any additives at 30 degrees C under an oxygen pressure. This result is unprecedented in ligand-on nanocluster catalysts without high temperature calcination. The distinct difference between their activities of Pd3Cl/TNT composite and fresh Pd3Cl nanocluster is explained by the presence of the MSI effect, as confirmed using X-ray photoelectron spectroscopy (XPS) analysis. Theoretical simulations are further carried out to elucidate the catalytic mechanism, indicating the MSI effect promotes the crucial beta-H elimination step in both kinetic and thermodynamic aspects. This work presents the example of atomic-level understanding of the effect of MSI on facilitating the APNCs catalytic properties.