Trace Cu-Regulated Pt Active Sites Confined in Nano-Islands for Furfural Hydrogenation

Abstract

Nanostructured island-confined metal catalysts offer remarkable stability; however, it is challenge to balance the activity and selectivity in multi-step reactions owing to the limited electronic modifications for individual metal systems. Here, we develop a strategy by integrating “nano-island confinement” with “dilute alloying”, in which ~0.7 nm Pt₉₅Cu₅ dilute alloy clusters are confined onto CeO_x nano-islands. As expected, this confinement not only suppresses metal migration and leaching, but also tailors the surface electronic structure via strong Pt-Cu coupling to regulate substrate adsorption and activation. Various characterizations reveal that the as-designed catalytic system maintains abundant active sites because of the nearly full exposure of Pt, and more importantly, downshifts the Pt d-band center through d-d hybridization within Pt-Cu dilute alloy. As a result, this configuration optimizes furfural adsorption behavior, and favors its planar adsorption instead of vertical one. DFT calculation further shows that planar-adsorption-driven hydrogenation remarkably enhances the reaction kinetics by reducing the barrier for FurCH₂O formation and accelerating proton-coupled electron transfer step. Compared with nano-island confined Pt catalyst, the confined Pt-Cu dilute alloy increases the TOF for furfural conversion from 849.3 to 1008.7 h^–1 and for furfuryl alcohol from 383.9 to 657.7 h^–1, and demonstrates remarkable stability under demanding conditions (150 °C, 3 MPa H₂). These results demonstrate that the nano-islands confined dilute alloy strategy is promising for effectively maintaining metal stability and adjusting activity-selectivity balance.

Keywords

Nano-island / Confined catalysis / Diluted alloy / Furfural hydrogenation / d-d hybridization / d-band center / Adsorption configuration / Pt-Cu

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