Ligand‐Sharing‐Mediated Synthesis of Intermetallic FeM Clusters Embedded in Ultrathin γ‐Fe₂O₃ Nanosheets

Abstract

Precious metal intermetallic nanoclusters (IMNCs) are promising nanocatalysts for practical industrial applications. However, to date, the preparation of these nanoclusters has been restricted to harsh conditions, and only succeeds for a limited number of elements. This study developed a simple and efficient strategy that enables the synthesis of supported IMNCs under ambient conditions via inorganometallic coordination chemistry, specifically, by donating the Cl − ligand, a noble metal chloride (MCl a b− ) forms a heterobimetallic ion (M x Fe y Cl z n− ) with the coordination-unsaturated FeCl 3 . Upon reduction, the ordered heterobimetallic ions are simultaneously transformed into IMNCs and embedded into γ-Fe 2 O 3 nanosheets, which form from excess FeCl 3 . In addition to providing convincing spectral evidence for the structure of the heterobimetallic ions, magnetic measurements, atomicresolution electron microscopy, X-ray absorption spectroscopy, and Fourier transform infrared spectroscopy of chemisorbed CO collectively confirm the successful preparation of the L1 0 -phased Pd 3 Fe IMNCs. Furthermore, this versatile method can be extended to synthesize other IMNCs, such as AuFe and PtFe, and seems to be applicable to IrFe, RhFe, RuFe, and MCo. When utilized as a heterogeneous catalyst in a Heck coupling reaction, the prepared Pd 3 Fe IMNCs display satisfactory activity and stability, highlighting their potential applications as advantageous catalysts.

AuFe3@Pd/γ-Fe2O3 Nanosheets as an In Situ Regenerable and Highly Efficient Hydrogenation Catalyst

“…In this study, we developed AuFe 3 @Pd embedded in ultrathin γ-Fe 2 O 3 nanosheets (NSs) as an in situ regenerable and highly active hydrogenation catalyst, which could be recovered entirely from S 2– poisoning without activity loss or Pd leaching. We selected single-unit-cell-thickness ultrathin γ-Fe 2 O 3 NSs rich in surface defects and Fe Tetra vacancies as the direct support, which dual-functions as catalyst support and as activator for H 2 O 2 and PMS to generate •OH radicals for the in situ oxidative regeneration of poisoned Pd sites . The atomic layer of Pd was subsequently deposited onto intermetallic phased AuFe 3 nanocluster cores with a diameter of 2–3 nm, providing an optimized binding site for Pd and enhancing the chemical stability of Pd due to its strong interatomic interactions. ,, The distinctive coordination structures of AuFe 3 @Pd and γ-Fe 2 O 3 NSs were verified using atomic resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and X-ray adsorption spectroscopy (XAS).…”

“…We selected single-unit-cell-thickness ultrathin γ-Fe 2 O 3 NSs rich in surface defects and Fe Tetra vacancies as the direct support, which dual-functions as catalyst support and as activator for H 2 O 2 and PMS to generate •OH radicals for the in situ oxidative regeneration of poisoned Pd sites . The atomic layer of Pd was subsequently deposited onto intermetallic phased AuFe 3 nanocluster cores with a diameter of 2–3 nm, providing an optimized binding site for Pd and enhancing the chemical stability of Pd due to its strong interatomic interactions. ,, The distinctive coordination structures of AuFe 3 @Pd and γ-Fe 2 O 3 NSs were verified using atomic resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and X-ray adsorption spectroscopy (XAS). The γ-Fe 2 O 3 NSs triggered generation of •OH radicals, and the in situ regeneration of S 2– poisoned AuFe 3 @Pd/γ-Fe 2 O 3 NSs was monitored using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS).…”

Critical Review of Pd-Catalyzed Reduction Process for Treatment of Waterborne Pollutants

“…2 In this strategy, we employed atomic layer thick (∼2.0 nm) γ-Fe 2 O 3 nanosheets (NSs) as the primary support for the Pd catalyst (Figure 7f). 103 The existence of highly coordinated unsaturated Fe sites (with Fe−O coordination number of 3) and the rich Fe tert -vacancy sites, as revealed in the Fe k-edge EXAFS spectra, allows the NSs to be highly active in generating •OH radicals. This activity is attributed to the activity of NSs in triggering the activation of H 2 O 2 and PMS, thereby facilitating the regeneration of Pd sites that have been poisoned by S 2− or fouled by strongly adsorbed phenol.…”

Intermetallic Nanocrystals for Fuel-Cells-Based Electrocatalysis

“…Akin to Pt-based nanocrystals, senior morphology and facet control also takes up a prominent position when ameliorating the electrocatalytic performances of Pd-based intermetallics. Various bizarre appearances have been achieved in this area for recent years, including PdCu/Pd 3 Pb nanocubes, ,,− Pd 3 Pb nanodendrites, PdCu/Pd 3 Pb nanowires, ,, Pd 3 Pb square nanoplates, , PdFe ultrathin nanosheet assembly, Pd 3 Pb concave nanocubes, Pd 2 Sn ultrathin porous nanosheets, Pd 3 Sn/PdCuSn nanorods, PdSb rhombohedra, Pd 8 Sb 3 hexagonal nanoplates, PdZn nanosheets, and so on. Deliberate exposure of specific facets, especially unconventionally tensile-strained {111} and {100} facets and high-index facets with particular coordination environment and activity-enhanced reaction sites, greatly fosters the intrinsic activity of Pd-based intermetallics.…”

“…Beyond the core/shell precursors, the other heterostructures containing metals and metal oxides, which can generate abundant O vacancies under high-temperature environment, are also desired precursors for preparing intermetallics by annealing. ,− An ideal starting platform, dumbbell-like PtFe–Fe 3 O 4 nanoparticles, can promote the formation of ordered PtFe nanoparticles . Specifically, Fe 3 O 4 –FePt heterostructural nanoparticles were synthesized by using Pt­(acac) 2 and Fe­(CO) 5 as the precursors and the air as the oxidant.…”