Inhibition of carbon formation during steam reforming of methane using thiol-coated nickel catalysts

n-Butanethiol-impregnated, micrometric, pristine Ni powder (Ni–C4S) was tested as a catalyst for use in the steam reforming of methane, using X-Ray photoemission spectroscopy (XPS) and mass spectrometry (MS). The catalytic activities of both the pristine Ni and the Ni–C4S powders were measured at 700 °C, under conditions that favoured (molar CH4:H2O ratio of 2:1), and did not favour (molar CH4:H2O ratio of 1:2) formation of surface carbon. The results show that: (a) Ni–C4S demonstrates both high catalytic activity and stability during the 21 h duration test; (b) under conditions favouring the deposition of surface carbon, the Ni–C4S retained both its efficiency and structural integrity, while the catalytic activity of the Ni was reduced by ~70% and the catalyst pellets lost their integrity; (c) the amount of deposited carbon in the case of the Ni–C4S catalyst was significantly lower than that observed for the Ni catalyst, in spite of the longer testing duration. It was concluded that the thiols pre-treatment of Ni surfaces, to be subsequently used in the production of catalysts supported SOFC anodes, can considerably increase their “active life span” this being a critical attribute in respect of their eventual commercialization.