Catalytic methanation performance in a low-temperature slurry-bed reactor over Ni-ZrO2 catalyst: effect of the preparation method

摘要

Ni-ZrO2 catalysts were prepared by three different methods, i.e., sol-gel, solution combustion, and co-precipitation method. The obtained catalysts were characterized by N-2-physisorption, X-ray diffraction, temperature-programmed reduction of H-2, transmission electron microscopy, H-2-chemisorption, temperature-programmed desorption of CO, and X-ray photoelectron spectroscopy, and investigated for CO methanation reaction in a slurry-bed reactor under the conditions of 260 A degrees C, 1.0 MPa, H-2/CO ratio of 3, and space velocity of 6000 mL h(-1). The results show that Ni-ZrO2 catalyst prepared by the sol-gel method exhibited higher Ni dispersion, larger metal surface area, and stronger interaction between NiO and support than those of catalysts prepared by the solution combustion and co-precipitation method. The catalytic performance tests demonstrate that the preparation method strongly affected the catalytic activity for CO methanation by promoting the dispersion of Ni species, decreasing the catalyst particle size, and intensifying the CO adsorption. Accordingly, the sol-gel prepared Ni-ZrO2 catalyst exhibits the optimal CO conversion of 61.6 %, while the co-precipitated Ni-ZrO2 catalyst shows the worst one.