Syngas Production by Dry and Steam Reforming of a Model Biogas over Highly Active Bimetallic Co-Ir/Al2O3 Catalysts

Cobalt-based catalysts using aluminum oxide as a support and 0.025–0.10 wt.% iridium as a second metal were prepared by the impregnation method and tested in steam and dry reforming of a model biogas with a ratio of CH4:CO2 = 1:1. The processes were carried out in a fixed bed flow reactor under atmospheric pressure with a gas hourly space velocity of 1000–1500 h−1, and temperature varied in the range of 300–800 °C. The BET surface area, XRD, SEM, TEM, and H2-TPR methods were conducted to characterize the physicochemical properties of the “fresh” and “spent” samples of catalysts. The catalysts exhibit high and stable activity in the production of syngas from the biogas. Methane was almost completely converted at 750–800 °C in the steam reforming of biogas. Stability tests over 80–100 h confirmed the catalyst’s stable operation. Syngas with a ratio of H2/CO~0.9 is formed in dry reforming of biogas, while in steam reforming the ratio exceeds 1. It is believed that the addition of iridium to Co/Al2O3 causes improvement of catalyst performance due to a synergetic effect because of the interaction between Co and Ir.