Kinetic study of the methane dry (CO2) reforming reaction over the Ce0.70La0.20Ni0.10O2−δ catalyst

Abstract

The kinetic behaviour of the Ce_0.70La_0.20Ni_0.10O_2−δ catalyst during the methane dry reforming reaction was investigated in a fixed bed reactor in the temperature range of 923–1023 K with the partial pressure of CH₄ and CO₂ ranging between 5 and 50 kPa. The experimental data were fitted using the empirical power-law rate equation and Langmuir–Hinshelwood kinetic models proposed in literature for the Ni–La₂O₃ catalytic system and based on two-step single- and dual-site mechanisms. The obtained fitting results, after statistical and thermodynamic discrimination, showed that the mechanism of the dry reforming reaction over the Ce_0.70La_0.20Ni_0.10O_2−δ catalyst could be successfully described by the two-step dual-site mechanism. The activation energies for the CH₄ consumption from the power law and Langmuir–Hinshelwood models were estimated to be 91.5 and 136.9 kJ mol⁻¹, respectively. The lower activation energies for the CO₂ consumption (70.2 and 100.6 kJ mol⁻¹ from both models) suggested that the CO₂ activation should faster than CH₄. The basic nature of the Ce–La–O sites catalyzed the CO₂ conversion to oxy-carbonate, decreasing the CO₂ activation energy compared to that of CH₄.