Does shaping catalysts modify active phase sites? A comprehensive in situ FTIR spectroscopic study on the performance of a model Ru/Al2O3 catalyst for the CO methanation

Routinely, it seems assumed that the catalytic layer coated on monoliths and microchannel reactors preserve the properties of the initial powder catalyst. However, this assumption should be reasonably demonstrated since the set of chemical and physical manipulations involved in the preparation of these catalytic devices hardly does not alter the surface of the starting catalyst…

High-performance and low-cost macroporous calcium oxide based materials for thermochemical energy storage in concentrated solar power plants

High energy density, cycling stability, low cost and scalability are the main features required for thermochemical energy storage systems to achieve a feasible integration in Concentrating Solar Power plants (CSP). While no system has been found to fully satisfy all these requirements, the reversible CaO/CaCO3 carbonation reaction (CaL) is one of the most promising since CaO…

Effects of the speed ratio on the efficiency of planetary mills

The ignition time (tig) of the mechanically induced self-sustaining reaction (MSR) process involving the formation of TiB2 from Ti/2B elemental mixtures was used to study the influence of the ratio (k = -ωv/ωd) between the rotational speed of the supporting disc (ωd) and vials (ωv) on the milling efficiency of a Pulverisette 4 planetary mill. The variation of the inverse…

Electrical properties of bismuth ferrites: Bi2Fe4O9 and Bi25FeO39

Bi2Fe4O9 was prepared by solid-state reaction and the electrical properties measured by impedance spectroscopy. After annealing in O-2 at 900 degrees C, Bi2Fe4O9 is an electrically-homogeneous insulator. Its high frequency permittivity is constant (similar to 14.1) over the temperature range 300-400 degrees C and shows no evidence of incipient ferroelectricity at lower temperatures. On annealing…