Dry reforming of model-biogas over ceria-supported nickel catalyst: the effect of charge enhanced dry impregnation on the catalytic performance and coke resistance

Abstract

In this study, we investigated the effectiveness of charge charge-enhanced dry impregnation (CEDI) method on a ceria-supported nickel-based catalyst (10Ni/CeO₂) used to produce synthesis (syngas) under biogas dry reforming conditions. The CEDI method was used to enhance the electrostatic adsorption of nickel precursor onto the ceria support during dry impregnation (DI), hence charge-enhanced dry impregnation. The other ceria-supported nickel-based catalyst (labelled 10Ni/CeO₂-DI) was prepared by the commonly used DI method and used as the reference catalyst. The catalysts were then tested for stability and catalytic performance (biogas conversion and syngas yield) under biogas reforming conditions using CatLab-QGA equipment supplied by Hidden Analytical. The characterisation studies: X-ray diffraction (XRD), N₂ adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), oxygen temperature programmed oxidation (O₂-TPO), temperature programmed reduction (TPR), and H₂-chemisorption were performed on the fresh and spent catalysts to gain insight into the influence of the CEDI method on dispersion, nanoparticles size of the active phase, metal-support interaction, bulk composition, and phase composition. The results showed that enhancing electrostatic attraction during the DI method produced 10Ni/CeO₂-CEDI with smaller nanoparticles (3.33 nm), improved nickel dispersion from 1.40 to 5.04% and improved metal-support interaction inferred from TPR values increased from 290 to 340 °C. These favourable physicochemical properties had a positive correlation with the improvement in the conversion of model biogas feed and the least coke formation.