Effects of MoO3 loading and calcination temperature on the activity of the sulphur-resistant methanation catalyst MoO3/γ-Al2O3

The effects of calcination temperature and MoO3 loading on the syngas methanation performance of MoO3/γ-Al2O3 catalyst prepared by the incipient-wetness impregnation method were studied. Mo–Al/25 catalyst (∼4.04 Mo/nm2) calcined at 600 °C reached maximum activity with 46.45% CO conversion. All of the experimental results demonstrated that the saturated monolayer coverage of MoO3 over a γ-Al2O3 support was closet to 25 wt.% MoO3. It was discovered that tetrahedrally coordinated Mo6+ (T), instead of octahedrally coordinated Mo6+ (O), is the active catalytic precursor in its oxidised state. Additionally, it was also confirmed that the presence of crystalline MoO3 and Al2(MoO4)3 species depended on not only the MoO3 loading but also the calcination temperature.

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► The catalysts for syngas methanation were studied in the feed containing H2S.
► Mo–Al/25 catalyst calcined at 600 °C had the greatest surface and highest activity.
► The saturated monolayer coverage was proved to be closet to 25 wt.% MoO3.
► Octahedrally coordinated Mo6+ (O) species was not the active catalytic precursor.