In silica supported iron Fischer–Tropsch catalysts, promotion with copper strongly enhances both hematite reduction and magnetite carbidisation, while potassium promotion hinders reduction of hematite to magnetite but enhances magnetite carbidisation in carbon monoxide.
New dinuclear lanthanide pivalate complexes [Tb2(piv)6(Hpiv)6], [Tb2(piv)6(bpy)2], [Tb2(piv)6(phen)2], [Tb2(piv)6(bath)2]·1.5EtOH, and [Eu2(piv)6(bath)2]·2EtOH, as well as the coordination polymer {Tb(piv)3}n, in which piv = (CH3)3CCO2–, bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline, bath = 4,7‐diphenyl‐1,10‐phenanthroline, and EtOH = ethanol, were synthesized and characterized by X‐ray diffraction. For the terbium complexes, the magnetic properties and the solid‐state thermolysis were investigated. The phase composition of the solid decomposition products was determined by X‐ray powder diffraction. The photophysical properties of these complexes were analyzed by luminescence, excitation, and phosphorescence spectroscopy, and by lifetime measurements. A comparison of the photophysical data for bpy, phen, and bath complexes shows that the supramolecular organization affects the efficiency of the sensitization of Ln3+ luminescence. All the results obtained provide good prospects for the use of dinuclear lanthanide pivalate complexes as efficient light‐conversion molecular devices (LCMD).
The mechanism of activation of silica‐supported iron catalysts for Fischer–Tropsch synthesis was investigated in syngas or carbon monoxide under transient and isothermal conditions using the in situ magnetic method. The catalyst activation proceeds in two steps and involves reduction of hematite into magnetite and magnetite carbidisation into Hägg carbide. Smaller supported iron particles exhibit higher rates of hematite reduction and magnetite carbidisation than the larger counterparts. The reduction of hematite to magnetite proceeds with similar rates in syngas and pure carbon monoxide, while magnetite can be carbidised more rapidly in carbon monoxide. The concentration of iron carbide was approximately 3 times higher after activation in CO relative to the activation in syngas.
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