Pascal Del-Gallo

Catalytic Methane Decomposition over Fe‐Al2O3

The presence of a Fe-FeAl2 O4 structure over an Fe-Al2 O3 catalysts is demonstrated to be vital for the catalytic methane decomposition (CMD) activity. After H2 reduction at 750 °C, Fe-Al2 O3 prepared by means of a fusion method, containing 86.5 wt % FeAl2 O4 and 13.5 wt % Fe(0) , showed a stable CMD activity at 750 °C for as long as 10 h.

Methane‐induced Activation Mechanism of Fused Ferric Oxide–Alumina Catalysts during Methane Decomposition

Activation of Fe2 O3 -Al2 O3 with CH4 (instead of H2 ) is a meaningful method to achieve catalytic methane decomposition (CMD). This reaction of CMD is more economic and simple against commercial methane steam reforming (MSR) as it produces COx -free H2 . In this study, for the first time, structure changes of the catalyst were screened during CH4 reduction with time on stream. The aim was to optimize the pretreatment conditions through understanding the activation mechanism. Based on results from various characterization techniques, reduction of Fe2 O3 by CH4 proceeds in three steps: Fe2 O3 →Fe3 O4 →FeO→Fe0. Once Fe0 is formed, it decomposes CH4 with formation of Fe3 C, which is the crucial initiation step in the CMD process to initiate formation of multiwall carbon nanotubes.

Development of chromium and aluminum coatings on superalloys by pack-cementation technique

Austenitic nickel-iron-chromium based superalloys are materials of choice for high temperature applications as they provide high temperature creep resistance associated with a suitable oxidation behavior in the temperature range of 600-1100°C. However, these properties are not sufficient for applications as Steam Methane Reformer (SMR). As a consequence, aluminum and chromium coatings are developed by the pack-cementation technique to improve their corrosion resistance. The oxidation behavior of the coated samples has been carried out in air at 1050°C. Chromium deposition leads to a layer of bcc chromium-iron solid solution. Oxidation tests indicated that a too high chromium concentration induces a too rapid growth of the chromia layer. In the case of aluminum coatings, a layer of -NiAl is formed at the surface of the alloy. It permits a significant decrease of the oxidation rate.