Syngas production via C3H8 dry reforming: Effect of Co and Mo addition on Ni/Al2O3 catalyst

Abstract

Dry reforming of propane has been carried out over alumina-supported 5wt%Co–10wt%Ni and 5wt%Mo–10wt%Ni catalysts. Catalysts were characterised using liquid N2 adsorption, H2 chemisorption, XRD, temperature-programmed desorption of NH3 and CO2, temperature-programmed reduction (with H2) as well as oxidation of spent catalysts. Time-on-stream analysis revealed that Mo–Ni catalyst has higher H2, CO and CO2 but lower CH4 formation rates compared to Co–Ni catalyst, while H2:CO ratio were almost the same in both catalysts. However, conversion-time analysis showed that Mo–Ni catalyst was more stable and active during a 72h run while Co–Ni suffered noticeable deactivation after 30h of reaction. Reaction–deactivation models implicated a higher deactivation coefficient (kd) with activation energy of Ed=78.1kJmol−1 for Co–Ni catalyst, while Mo–Ni showed lower deactivation coefficient with smaller activation energy (Ed=69.4kJmol−1). Post-mortem analysis (TOC and TPR-TPO) of spent catalysts confirmed that the surface of Co–Ni catalyst has more carbon residue than the Mo–Ni sample consistent with the higher deactivation of Co–Ni.