Organic Additive Assisted Ordered Mesoporous Ni/Al2O3 Catalyst for CO2 Methanation

摘要

A trimethylbenzene (TMB) assisted ordered mesoporous Ni/Al2O3 catalysts were prepared by a one-pot evaporation-induced self-assembly (EISA) method for CO2 methanation to solve the problems of high-temperature sintering of Ni particle and poor low-temperature activity of Ni-based catalysts. For comparison, we also prepared the catalysts without TMB or with different amount of NiO loadings. These samples were characterized by nitrogen adsorption, X-ray diffraction, H-2 temperature programmed reduction, scanning electron microscopy and transmission electron microscopy. The structure of the ordered mesoporous Ni/Al2O3 catalyst was modified by TMB to obtain a high specific surface area and a smaller pore size, resulting in the smaller Ni particles size and the higher metal dispersion. These changes could increase the interaction between the Ni species and the support, which effectively solved the problem of high temperature Ni sintering and low temperature activity. The mesoporous TMB-assisted ordered mesoporous Ni/Al2O3 catalysts catalyst reached the maximum CO2 conversion and CH4 yield of 74.61 and 88.27 %, respectively at 425 degrees C, 0.1 MPa and a weight hourly space velocity of 60,000 mL g(-1) h(-1). In addition, the catalyst showed excellent stability in 100 h-lifetime test at high space velocity owing to the confinement of the ordered mesoporous structure as well as the modification of catalyst structure by TMB.