Direct Dry Synthesis of Supported Bimetallic Catalysts: A Study on Comminution and Alloying of Metal Nanoparticles.

Ball milling is growing increasingly important as an alternative synthetic tool to prepare catalytic materials. It was recently observed that supported metal catalysts could be directly obtained upon ball milling from the coarse powders of metal and oxide support. Moreover, when two compatible metal sources are simultaneously subjected to the mechanochemical treatment, bimetallic nanoparticles are obtained.

Surface and Bulk Chemistry of Mechanochemically Synthesized Tohdite Nanoparticles.

Aluminum oxides, oxyhydroxides, and hydroxides are important in different fields of application due to their many attractive properties. However, among these materials, tohdite (5AlO·HO) is probably the least known because of the harsh conditions required for its synthesis. Herein, we report a straightforward methodology to synthesize tohdite nanopowders (particle diameter ∼13 nm, specific surface area ∼102 m g) via the mechanochemically induced dehydration of boehmite (γ-AlOOH).

Mechanochemical Synthesis of Catalytic Materials.

The mechanochemical synthesis of nanomaterials for catalytic applications is a growing research field due to its simplicity, scalability, and eco-friendliness. Besides, it provides materials with distinct features, such as nanocrystallinity, high defect concentration, and close interaction of the components in a system, which are, in most cases, unattainable by conventional routes. Consequently, this research field has recently become highly popular, particularly for the preparation of catalytic materials for various applications, ranging from chemical production over energy conversion catalysis to environmental protection.

Single-crystal-to-single-crystal post-synthetic modifications of three-dimensional LOFs (Ln = Gd, Eu): a way to modulate their luminescence and thermometric properties.

Single-crystal-to-single-crystal post-synthetic modifications (PSMs) of Lanthanide Organic Frameworks (LOFs) {[Ln(HL)(DMF)]·2DMF} (Ln = Gd, 1 and Eu, 2; HL = 2,5-dihydroxyterephthalic acid; DMF = dimethylformamide), carried out by treatment with (a) chloroform or (b) an imidazole solution in chloroform, yielded respectively isostructural {[Ln(HL)(DMF)]·CHCl} (Ln = Gd, 3; Eu, 4) or {[Ln(HL)(Im)][Ln(HL)(Im)(HO)]·6Im·2CHCl} (Ln = Gd, 5; Eu, 6). Single crystal X-ray diffraction studies of 5 showed two different regularly alternating dimeric units in the LOF and two regularly alternating cavities with different guest molecules. All compounds revert to the parent LOF, 1 or 2, when treated with DMF at 90 °C for 8 h.

Milling Down to Nanometers: A General Process for the Direct Dry Synthesis of Supported Metal Catalysts.

Supported catalysts are among the most important classes of catalysts. They are typically prepared by wet-chemical methods, such as impregnation or co-precipitation. Here we disclose that dry ball milling of macroscopic metal powder in the presence of a support oxide leads in many cases to supported catalysts with particles in the nanometer size range.