Planar tetracoordinate fluorine atoms in binary M4F4
− (M = Li, Na) clusters have been predicted using quantum chemical methods.
 
Planar tetracoordinate fluorine (ptF) species are rare and exotic due to the extreme electronegativity of fluorine. Herein, a ptF species is predicted in the binary Li4F4
− and Na4F4
− clusters. The global minimum of the clusters features C
2v
 geometry and are stabilized by significant electrostatic interaction. Moreover, multicenter ionic bonds also play a vital role in the stability of the planar C
2v
 geometry. The present study establishes the first example of ptF center in binary alkali halide cluster.

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Planar Tetracoordinate Fluorine in Binary Clusters

Planar tetracoordinate fluorine atoms in binary M4F4 − (M = Li, Na) clusters have been predicted using quantum chemical methods. Planar tetracoordinate fluorine (ptF) species are rare and exotic due to the extreme electronegativity of fluorine. Herein, a ptF species is predicted in the binary Li...

The catalytic activity of gold in benzyl alcohol oxidation is enhanced by adding palladium, as long as it remains on the surface in a core-shell configuration. Palladium migration to the gold core (alloy formation) decreases activity, as shown by the volcano plot. Each gold core size requires a specific Pd amount for optimal activity.
 
The addition of palladium (Pd) to preformed gold nanoparticles (Au NPs) enables the formation of core-shell structures with enhanced catalytic performance in oxidation reactions. However, predicting the precise palladium content required to achieve maximum catalytic activity remains difficult based on current understanding. Herein, Pd was systematically introduced onto titania-supported Au NPs (2, 6, and 10 nm) to evaluate their performance in benzyl alcohol oxidation. A volcano-like trend in catalytic activity was observed, where activity increased with Pd addition, peaked, and then declined. The Pd loading required for maximum activity depended on Au NP size: ≈40 at% Pd/Au for 2.6 nm, ≈20 at% Pd/Au for 6.4 nm, and ≈12.5 at% Pd/Au for 10.6 nm. For Au NPs &gt; 6 nm, peak activity aligned with monolayer Pd coverage, while for smaller NPs (2–3 nm), optimal Pd content was below monolayer predictions. X-ray absorption spectroscopy revealed a core-shell structure at low Pd content, but higher Pd loadings led to Pd diffusion into the Au core. This structural transformation likely caused activity decline, indicating that AuPd alloying negatively impacts catalysis. These results highlight that core-shell Au@Pd catalysts outperform AuPd alloys and provide crucial insights for designing highly active bimetallic catalysts.

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Planar Tetracoordinate Fluorine in Binary Clusters

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Volcano‐like Activity Trends in Au@Pd Catalysts: The Role of Pd Loading and Nanoparticle Size

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