Sacrificial Carbon Strategy toward Enhancement of Slurry Methanation Activity and Stability over Ni-Zr/SiO₂ Catalyst

Mesoporous silica-supported Ni-Zr catalysts prepared via the modified impregnation method by applying different solvents and calcination atmospheres were employed for CO methanation in a slurry-bed reactor. The results show that the glycerol-impregnated Ni-Zr/SiO₂ catalyst exhibited higher specific surface area and Ni species dispersion and more intensive nickel–support interaction than the water-impregnated one and thus enhanced the catalytic activity and stability. Furthermore, the carbon could be constructed on the surface of the Ni-Zr/SiO₂ catalyst from the carbonization of glycerol via calcination under an inert atmosphere and be removed through successive calcination in air. Owing to the improved nickel–support interaction, the carbon-sacrificed Ni-Zr/SiO₂ catalyst exhibited higher Ni dispersion and smaller and more uniform Ni particle sizes, leading to catalytic activity for CO methanation that is higher than that of the catalysts without carbonization

A new class of Cu/ZnO catalysts derived from zincian georgeite precursors prepared by co-precipitation

Zincian georgeite, an amorphous copper-zinc hydroxycarbonate, has been prepared by co-precipitation using acetate salts and ammonium carbonate. Incorporation of zinc into the georgeite phase and mild ageing conditio ns inhibits crystallisation into zincian malachite or aurichalcite. This zincian georgeite precursor was used to prepare a Cu/ZnO catalyst, which exhibits a superior performance to a zincian malachite derived catalyst for methanol synthesis and the low temperature water-gas shift (LTS) reaction. Furthermore, the enhanced LTS activity and stability in comparison to that of a commercial Cu/ZnO/Al 2 O 3 catalyst, indicates that the addition of alumina as a stabiliser may not be required for the zincian georgeite derived Cu/ZnO catalyst. The enhanced performance is partly attributed to the exclusion of alkali metals from the synthesis procedure, which are known to act as catalyst poisons. The effect of residual sodium on the microstructural properties of the catalyst precursor was investigated further from preparations using sodium carbonate