Catalytic stability and surface analysis of microcrystalline Ni3Al thin foils in methanol decomposition

The research on the development of solid state catalyst is presented. In this study, the catalytic activity and catalytic stability tests of the Ni3Al thin intermetallic foils in methanol decomposition were investigated. The catalytic activity of Ni3Al started above 300 °C, and reached a maximum of methanol conversion (94%) at 500 °C. Carbon deposit formed during the catalytic tests was analyzed in details by SEM, BET, XRD, and Raman spectroscopy. It was found that the carbon deposit consists of well crystallized, curved multi-walled carbon nanotubes, and amorphous carbon, perhaps in the form of nanofibers, without single-walled carbon nanotubes. Despite the presence of various forms of carbon on the Ni3Al surface, the catalyst provides a good catalytic stability: even after 17 h of the reaction, the methanol conversion is 90%. At the ends of the obtained nanotubes/nanofibers one can see Ni nanoparticles. Moreover, it has been proven that the Ni nanoparticles are situated inside the carbon nanofibers/nanotubes, as well. The mechanism of the carbon deposit growth on Ni3Al thin foils was proposed.