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 multiwallcarbon nanotubes-supported nickel catalysts promoted by ceria. For comparison purposes, activatedcarbon-supported catalysts have also been studied. The catalytic performance and the characterizationby N2 adsorption analysis, powder X-ray diffraction (XRD), temperature-programmed reduction with H2(TPR-H2), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) analysisshowed that the surface chemistry has an important effect on the dispersion of ceria. As a result, ceriawas successfully dispersed over the carbon nanotubes (CNTs) with less graphitic character, and thecatalyst afforded better activity in WGS than the catalyst prepared over massive ceria. Moreover, a20 wt.% CeO2 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 thisresulted in a decrease of the activity.