Effect of Ni active site position and synthesis route on activity, stability, and morphology of Ce promoted Ni/Al2O3 catalyst for clean H2 production

Abstract

The main object of this research is investigation the effect of Ni active site position and synthesis route on the activity, stability, and morphology of Ce promoted Ni/Al2O3 catalyst applied in the steam reforming of methane (SRM) for producing H2-rich syngas with low CO2 contents. In the first step, the Ce promoted Ni/Al2O3 catalysts are synthesized via co-impregnation and co-precipitation methods with different Ni loading 10–25 % and Ce loading 0–3.0 %. The performance of synthesized catalysts to progress steam reforming reaction are tested in an experimental setup at temperature range 600–700 °C and steam to methane ratio 1.5–3.5. Besides the influence of CeO2 particles on the catalytic activity of Ni-based catalysts, their effect on Ni active sites dispersion is also investigated. The results depicted that integrated Ni-Al structure synthesized via co-precipitation method has a higher surface area, higher catalytic activity and stability, as well as stronger Ni-Al interaction compared to un-promoted impregnated samples. However, the 20Ni-1.5Ce/Al2O3 catalyst exhibits higher NiO crystallinity, stronger Ni-Al interaction, higher oxygen storage capacity (OSC), lower deposited coke, and thus higher catalytic activity during the SRM process. Based on the activity tests, 20Ni-1.5Ce/Al2O3 catalyst depicted the best performance for producing environmentally-friendly H2-rich syngas with the lowest amount of CO2 and CH4.