Influence of Solid Solution Formation on the Activity of CeO2 Supported Ni–Cu Mixed Oxide Catalysts in Dry Reforming of Methane

Abstract

A series of CeO2 supported 20 wt% Ni–Cu mixed oxide catalysts was prepared by co-impregnation, varying the Ni–Cu composition. The catalysts were characterized by nitrogen adsorption for BET surface area, X-ray diffraction (XRD), Temperature programmed reduction (TPR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), H2 Chemisorption, Scanning electron microscopy (SEM) and CHNS analysis techniques. They were evaluated for dry reforming of methane to produce syngas in the temperature range of 600–800 °C and at a GHSV = 28,800 h−1. 5 wt% Ni + 15 wt% Cu/CeO2 displayed superior activity among the series. The incorporation of Ni metal in CeO2 lattice led to the formation of Ni–O–Ce solid solution up to 5 wt% Ni in the catalyst. This catalyst also showed good stability due to less coke formation. Resistance towards coking was observed to be mainly due to the abundance of labile oxygen in the solid solution. Ni incorporation in CeO2 results in significant change in the CeO2 lattice leading to solid solution formation and enhancing metal dispersion. Increase in the oxygen storage capacity (OSC) with the addition of Cu helps improve catalyst stability.