Preparation of Different Nickel–Iron/Titania–Alumina Catalysts for Hydrogen/Carbon Monoxide Methanation under Atmospheric Pressure

Bimetallic Ni–Fe/TiO₂–Al₂O₃ catalysts were prepared by using the titania–alumina composite as a support, which was synthesized through three different methods (precipitation, co-precipitation, and sol–gel). The synthesized catalysts were characterized by X-ray diffraction, temperature-programmed reduction, and transmission electron microscopy. The catalytic performance of the catalysts for the methanation of syngas was studied under atmospheric pressure. Ni and Fe species were found to be highly dispersed on the TiO₂–Al₂O₃ composite prepared by the sol–gel method, which led to good catalytic performance for CO conversion (≈96.7 %) and methane selectivity (≈94.7 %) at lower temperatures. In addition, less amorphous carbon was deposited on the used Ni–Fe/TiO₂–Al₂O₃ catalyst prepared by the sol–gel method. This was ascribed to the evidenced core-in-shell structures (TiO₂ shell with Al₂O₃ core) of the TiO₂–Al₂O₃ composite prepared by the sol–gel method, which led to prominent stability of the catalyst (≈30 h). The results give an applicable guide for the highly efficient methanation of syngas under atmospheric pressure.