LaCoO3 is a promising catalyst for the dry reforming of benzene used as a surrogate of biomass tar.

Abstract

Tar build-up is one of the bottlenecks of biomass gasification processes. Dry reforming of tar is an alternative solution if the oxygen chemical potential on the catalyst surface is at a sufficient level. For this purpose, an oxygen-donor perovskite, LaCoO3, was used as a catalyst for the dry reforming of tar. To circumvent the complexity of the tar and its constituents, the benzene molecule was chosen as a model compound. Dry reforming of benzene vapor on the LaCoO3 catalyst was investigated at temperatures of 600, 700, and 800 °C; at CO2/C6H6 ratios of 3, 6, and 12; and at space velocities of 14,000 and 28,000 h-1. The conventional Ni(15 wt.%)/Al2O3 catalyst was also used as a reference material to determine the relative activity of the LaCoO3 catalyst. Different characterization techniques such as X-ray diffraction, N2 adsorption-desorption, temperature-programmed reduction, and oxidation were used to determine the physicochemical characteristics of the catalysts. The findings demonstrated that the LaCoO3 catalyst has higher CO2 conversion, higher H2 and CO yields, and better stability than the Ni(15 wt.%)/γ-Al2O3 catalyst. The improvement in activity was attributed to the strong capacity of LaCoO3 for oxygen exchange. The transfer of lattice oxygen from the surface of the LaCoO3 catalyst facilitates the oxidation of carbon and other surface species and leads to higher conversion and yields.