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 process. Dry reforming of tar is an alternative solution if oxygen chemical potential on the catalyst surface is at sufficient levels. For this purpose, an oxygen donor perovskite, LaCoO3, was used as a catalyst for dry reforming of tar. To circumvent the complexity of the tar and its constituents, benzene molecule was chosen as a model compound. Dry reforming of benzene vapour on the LaCoO3 catalyst was investigated at temperatures of 600, 700, 800 degrees C, at the CO2/C6H6 ratios of 3, 6, 12 and at space velocities of 14000 and 28000 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, N-2 adsorption-desorption, Temperature-programmed reduction, and oxidation were used to determine physicochemical characteristics of catalysts. The findings demonstrate that the LaCoO3 catalyst has a higher CO2 conversion, H-2 and CO yields and better stability than the Ni(15 wt.%)/gamma-Al2O3 catalyst. The improvement in activity is 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.