Nickel-based cerium zirconate inorganic complex structures for CO2 valorisation via dry reforming of methane

Abstract

The increasing anthropogenic emissions of greenhouse gases (GHG) is encouraging extensive research in CO₂ utilisation. Dry reforming of methane (DRM) depicts a viable strategy to convert both CO₂ and CH₄ into syngas, a worthwhile chemical intermediate. Among the different active phases for DRM, the use of nickel as catalyst is economically favourable, but typically deactivates due to sintering and carbon deposition. The stabilisation of Ni at different loadings in cerium zirconate inorganic complex structures is investigated in this work as strategy to develop robust Ni-based DRM catalysts. XRD and TPR-H₂ analyses confirmed the existence of different phases according to the Ni loading in these materials. Besides, superficial Ni is observed as well as the existence of a CeNiO₃ perovskite structure. The catalytic activity was tested, proving that 10 wt.% Ni loading is the optimum which maximises conversion. This catalyst was also tested in long-term stability experiments at 600 and 800°C in order to study the potential deactivation issues at two different temperatures. At 600°C, carbon formation is the main cause of catalytic deactivation, whereas a robust stability is shown at 800°C, observing no sintering of the active phase evidencing the success of this strategy rendering a new family of economically appealing CO₂ and biogas mixtures upgrading catalysts.

Keywords: CO(2) conversion; Cerium zirconate; Dry reforming of methane; Nickel catalysts; Pyrochlore.