Electrolyte effect on the catalytic performance of Ni-based catalysts for direct internal reforming molten carbonate fuel cell

An active and tolerant Ni-based catalyst for methane steam reforming in direct internal reforming molten carbonate fuel cells (DIR-MCFCs) was developed. Deactivation of reforming catalysts by alkali metals from the electrolyte composed of Li₂CO₃ and K₂CO₃ is one of the major obstacles to be overcome in commercialization of DIR-MCFCs. Newly developed Ni/MgSiO₃ and Ni/Mg₂SiO₄ reforming catalysts show activities of ca. 80% methane conversion. Subsequent to electrolyte addition to the catalyst, however, the activity of Ni/Mg₂SiO₄ decreases to ca. 50% of its initial value, whereas Ni/MgSiO₃ catalyst retains its initial activity. Results obtained from temperature-programmed reduction and X-ray photoelectron spectroscopy identify unreduced Ni³⁺ as a decisive factor in keeping catalytic activity from the electrolyte.