Characterization of surface processes at the Ni-based catalyst during the methanation of biomass-derived synthesis gas: X-ray photoelectron spectroscopy (XPS)

Surface modifications of Ni/Al 2O 3 catalyst during the production of methane from reformer synthesis gas were investigated by quasi in situ XPS. The influence of biomass-derived synthesis gas compounds on the surface properties of the catalyst and on its activity under methanation conditions was studied. A mechanism of carbon whiskers formation during long exposure to methanation conditions is also described. ▪ Surface modifications during the production of methane from reformer synthesis gas over a commercial Ni/Al 2O 3 catalyst were investigated by quasi-in situ X-ray photoelectron spectroscopy (XPS) and other surface analytical techniques. Experiments of methanation reaction were done in the high pressure cell (HPC) integrated in the XPS system and under fixed-bed conditions. The interaction of the different reformer biomass-derived synthesis gas on the surface properties of the catalyst and on its activity under methanation conditions were studied on a nanoscopic level. Detailed description of changes in metal particle morphology and carbon deposit is presented. A mechanism of C-whiskers formation during long exposure to methanation conditions is described. The role of additional components in the gas mixture, such as CO 2, H 2O, CH 4, C 2H 4, C 2H 2, C 3H 6 and C 2H 6, were studied in details. Furthermore, role of different nickel compounds such as oxides, hydroxides, carbides and carbonates are discussed.