Iron Oxide over Silica-Doped Alumina Catalyst for Catalytic Steam Reforming of Toluene as a Surrogate Tar Biomass Species

An iron oxide over silica-doped alumina catalyst was successfully synthesized using one-pot, solvent-deficient method. The prepared Fe₂O₃/SiO₂-Al₂O₃ catalyst was characterized using TGA/DTG, XRD, N₂ adsorption isotherm, NH₃-TPD, and SEM. The TGA/DTG and XRD results show that the presence of Si enhances the stability of γ-Al₂O₃ support at high temperatures. The prepared Fe₂O₃/SiO₂-Al₂O₃ catalyst was obtained by calcination at 950 °C, with a high BET specific surface area (49 m²/g). The NH₃-TPD showed that Fe addition can significantly increase catalyst acidity. SEM images confirmed the textural properties of the catalysts in term of surface morphology. The catalytic activity of Fe₂O₃/SiO₂γ-Al₂O₃ catalysts was examined in a CREC fluidized riser simulator using toluene as model compound for biomass tar. Experiments with this catalyst yielded high toluene conversions. Composition of gases produced (H₂, CO, CO₂, and CH₄) were close to chemical equilibrium at 25 s and 600 °C. These results indicate that the Fe₂O₃/SiO₂-Al₂O₃ catalyst is a promising fluidizable catalyst for tar reduction. This novel supported metal oxide catalyst has a great potential for industrial use since it is a relatively cheap, less toxic, and long-lasting operation.