Carbon nanotube-supported Ni–CeO2 catalysts. Effect of the support on the catalytic performance in the low-temperature WGS reaction

Abstract

The low temperature water-gas shift (WGS) reaction has been studied over two commercial multiwall carbon nanotubes-supported nickel catalysts promoted by ceria.For comparison purposes, activated carbon-supported catalysts have also been studied.The catalytic performance and the characterization by N 2 adsorption analysis, powder X-ray diffraction (XRD), temperature-programmed reduction with H 2 (H 2 -TPR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysis showed that the surface chemistry has an important effect on the dispersion of ceria. As a result, ceria was successfully dispersed over the carbon nanotubes (CNTs) with less graphitic character, and the catalyst afforded better activity in WGS than the catalyst prepared over massive ceria. Moreover, a 20 wt.% CeO 2 loading over this support was more active than the analogous catalyst with a 40 wt.% loading. The ceria nanoparticles were smaller when the support was previously oxidized, however this resulted in a decrease of the activity.

Selective hydrogen production from formic acid decomposition over Mo carbides supported on carbon materials

“…This can explain straightforwardly the lower activity of 20Mo x C/H 400 and suggests that in the studied system, above 10% wt Mo there is an optimum loading before particles tend to form large agglomerates that diminish the active area, as observed in other carbon-supported systems. 25 A similar and even more clear effect is observed for the catalysts supported on H 200 .…”

Nickel‐based Catalysts for High‐temperature Water Gas Shift Reaction‐Methane Suppression

“…Based on this observation the mechanism of formation of carboxylate pathway as shown in Figure has been postulated and reported. In other works,, the interactions between Ni and CeO 2 were enhanced when CeO 2 in support is dispersed over CNTs. Upon dispersion the crystallite size of CeO 2 was decreased by almost three times than the crystallite size of CeO 2 in bulk form.…”

A review of recent advances in water-gas shift catalysis for hydrogen production

“…Carbon nanofibers (CNF) is another promising alternative to metal oxide-based supports due to the unique structural characteristics that enhance the metal and support interactions. They also have high mechanical strength, high electrical conductivity, and specific surface area, which is suitable for formation and anchoring of smaller metal nanoparticle [146]. Oliveira, Valençaa, and Vieira studied both Cu/CNF and Cu/Al 2 O 3 catalysts for the WGS reaction at a temperature range of 398-573 K [147].…”