Methane Decomposition Over ZrO₂-Supported Fe and Fe-Ni Catalysts-Effects of Doping La₂O₃ and WO₃

A leading method for hydrogen production that is free of carbon oxides is catalytic methane decomposition. In this research, Fe and Fe-Ni supported catalysts prepared by the wet impregnation method were used in methane decomposition. The effects of doping the parent support (ZrO₂) with La₂O₃ and WO₃ were studied. It was discovered that the support doped with La₂O₃ gave the best performance in terms of CH₄ conversion, H₂ yield, and stability at the test condition, 800°C and 4,000-ml h^-1 g^-1 cat. space velocity. The addition of Ni significantly improved the performance of all the monometallic catalysts. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), temperature-programmed reduction/oxidation (TPR/TPO), thermogravimetric analyzer (TGA), and microscopy (SEM and Raman) techniques. Phases of the different forms of Fe were identified by XRD. BET showed a drastic decline in the specific surface area of the catalysts with respect to the supports. TPR profiles revealed a progressive change in the valency of Fe in its combined form to the zero valence-free metal. The La₂O₃-promoted support gave the best performance and maintained good stability during the time on stream.