Combustion Synthesis during Flame Spraying (“CAFSY”) for the Production of Catalysts on Substrates

Combustion-assisted flame spraying (“CAFSY”) has been used to produce catalytically active nickel aluminide coatings on ceramic substrates. Their catalytic activity was studied in CO₂ (dry) reforming of methane, which is particularly significant for environmental protection as well as production of synthesis gas (CO + H₂). By varying the CAFSY processing parameters, it is possible to obtain a range of Ni–Al alloys with various ratios of catalytically active phases on the substrate. The influence of the number of coating layers and the type of substrate on the final catalyst composition and on the catalytic activity of the CAFSY coatings was studied and is presented here. The morphology and microstructure of the composite coatings were determined by scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) elemental analysis, X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) specific area analysis. Catalytic tests for dry reforming of methane were carried out using crushed pellets from the coatings at temperatures of 750–900 °C, and gas chromatography showed that methane conversion approached 88% whereas that of carbon dioxide reached 100%. The H₂/CO ratio in the synthesis gas produced by the reaction varied from about 0.7 to over 1.2, depending on the catalyst and substrate type and testing temperature.