Role of perovskites phase in Ni-based catalysts for low temperature CO2 methanation

Abstract

Listen

Translate article

CO2 methanation is considered as a promising reaction in the context of mitigating climate change by reducing CO2 emissions and providing a renewable source of methane fuel. The CeNiO3 and LaNiO3 perovskite catalysts were synthesized using the sol-gel method. The effect of perovskite structure on the catalytic activity was studied. The results were compared with Ce-supported and La-supported Ni catalysts (Ni/CeO2 & Ni/La2O3). Different methods including XRD, N2 adsorption-desorption, H2-TPR, FE-SEM, and CO2-TPD, were employed for the characterization of the catalysts. The perovskite catalysts are more active than the corresponding supported catalysts. Among all prepared catalysts CeNiO3 perovskite catalyst showed highest activity 80% conversion and 98% selectivity at 300 °C. Weak basicity, high active metal reducibility and the synergy between Ni and Ce due to perovskite structure are the responsible factors for high activity of CeNiO3 catalyst. The CeNiO3 catalyst showed excellent stability for CO2 methanation during 24 h of time on study with different GHSVs. The effect of calcination temperature was also studied on CeNiO3 catalyst at 650, 750 and 850 °C temperatures. Raman spectra concluded that the oxygen vacancy sites increased with rise of calcination temperature from 650 to 750 °C and decreased with further increase in temperature. The CeNiO3 calcined at 750 °C (CeNiO3-750) showed highest activity among all other catalysts. The increased activity is due to increased oxygen vacancies which ensures that Ni nanoparticles are highly dispersed.