Supported nickel catalysts for low temperature methane steam reforming: comparison between metal additives and support modification

Abstract

The effect of Ag (1 wt%) and Au (1 wt%) on the catalytic properties of Ni/Al 2 O 3 (7 wt% Ni) for methane steam reforming (MSR) was studied in parallel with the effect of CeO 2 (6 wt%) and La 2 O 3 (6 wt%) addition. The addition of 1 wt% Ag to the alumina supported nickel catalyst drastically decreased its catalytic properties at temperatures lower than 600°C, due to the blockage of metal catalytic centers by silver deposition. The addition of Au and CeO 2 (La 2 O 3 ) to the nickel catalyst improved the methane conversion, CO 2 selectivity and hydrogen production at low reaction temperatures (t \ 600°C). At 700°C under our working conditions, the additives have no important effect in hydrogen production by MSR. The best hydrogen production at low temperatures was obtained for Ni-Au/Al 2 O 3 , due to the higher CO 2 selectivity, cumulated with slightly higher methane conversion in comparison with Ni/CeO 2 -Al 2 O 3 . At high temperature, Ni/CeO 2 -Al 2 O 3 is stable for 48 h on stream. are mainly deactivated due to the temperature effect on Au and Ag nanoparticles and less through coke formation. On , crystalline, graphitic carbon was deposited after 48 h of reaction leading to catalyst partial deactivation. On the Ni/CeO 2 -Al 2 O 3 surface, a porous amorphous form of deposited carbon was found, which does not decrease its catalytic activity after 48 h of reaction.Electronic supplementary material The online version of this article (

Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

“…The impregnated catalysts were dried at room temperature overnight, calcined in Ar at 823 K and then, reduced in H 2 at 823 K. Taking all characterization results (XRD, H 2 chemisorption and TEM) into account, they concluded that in the Ni-Au/γ-Al 2 O 3 catalysts prepared by co-impregnation and reduced at 823 K, no significant interaction of Au with Ni has been proved to appear and no formation of a superficial Au-Ni surface alloy was observed [24]. Maniecki et al [25] have also prepared 2.0 wt% Au-10.0 wt% Ni/Al 2 O 3 catalysts by co-impregnation method and found that the addition of gold improved catalyst stability and activity in POM reaction.…”

“…Recently, Lazar et al [22][23][24] have synthesized the 1.0 wt% Au-7.0 wt% Ni/γ-Al 2 O 3 catalyst by co-impregnation method and found that the addition of Au improved the methane conversion, CO 2 selectivity and H 2 production at low temperatures (T < 600 °C). The impregnated catalysts were dried at room temperature overnight, calcined in Ar at 823 K and then, reduced in H 2 at 823 K. Taking all characterization results (XRD, H 2 chemisorption and TEM) into account, they concluded that in the Ni-Au/γ-Al 2 O 3 catalysts prepared by co-impregnation and reduced at 823 K, no significant interaction of Au with Ni has been proved to appear and no formation of a superficial Au-Ni surface alloy was observed [24].…”

“…Moreover, on the Au containing bimetallic catalyst the formation of carbon nanotubes was retarded or vanished, in the experimental conditions investigated. Furthermore, Lazar et al [22][23][24] have found that the addition of Au to the nickel catalyst improved the methane conversion, CO 2 selectivity and hydrogen production at low reaction temperatures (T < 873 K). At 973 K under their working conditions, the additives had no important effect in hydrogen production by methane steam reforming, and the catalysts deactivated.…”

“…Lazar et al [22][23][24] have reported that the addition of Ag decreased the catalytic properties of Ni catalyst. The catalysts with Ag loading of 0.3 or 0.6 wt% submitted to stability tests showed high resistance to coke deposition reported by Bueno et al [32].…”

Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes

“…1. As revealed only the diffraction peaks that correspond to c-Al 2 O 3 were observed but distinct peaks that correspond to either the metallic platinum or the rare earth were not observed may be due to their low concentration and their diffusion and inclusion in the alumina matrix without affecting the alumina matrix agglomeration mode or incapability to rearrange its characteristic agglomeration phase [13]. Such elucidation is supported by HRTEM images, where particles grain size of alumina support seems unchanged upon loading with the noble metal or the rare earth elements, Fig.…”