Promotion Effects of Nickel Catalysts of Dry Reforming with Methane

Abstract

Abstract The promotion effects of nickel catalyst of dry reforming with methane were extensively investigated by means of XRD, SEM, EDX, N 2 ‐adsorption and H 2 ‐adsorption. XRD characterization indicated that good dispersion of nickel oxide and MgO promoter is achieved over γ‐Al 2 O 3 support. Addition of MgO promoter effectively retards the formation of NiAl 2 O 4 phase. SEM and EDX analysis exhibited that the addition of rare‐earth metal oxide CeO 2 effectively promotes the Ni metal dispersion on the surface of the catalysts despite of undesirable self‐dispersion of CeO 2 promoter. Furthermore, the nickel component is gradually dispersed on the surface of the support following the exposure to reaction gas mixture for a period of time. The addition of MgO inhibited the self‐dispersion and promotion effect of CeO 2 on Ni dispersion on the catalysts. H 2 chemisorption revealed that the addition of the alkaline oxide MgO promoter significantly prohibits the metal dispersion on the catalyst. Inappropriate promoter addition can result in sharp decrease of the metal dispersion, N 2 ‐adsorption indicated that oxide promoter was mostly concentrated on the outer layer of the alumina support while the nickel metal was generally dispersed in the support pores. Addition of promoters contributed to more reduction in mesopore volume.