Enhancement of magnesium aluminate-based nickel and cobalt nanostructured catalysts with iron for improved performance in carbon dioxide methanation

Abstract

This study investigates the performance of Ni and Co catalysts based on Fe-promoted MgAl₂O₄ for CO₂ methanation, which is a crucial step in mitigating environmental carbon dioxide levels. The MgAl₂O₄ support was modified with various Fe loading (5, 10, and 15 ​wt%) and fabricated via a novel coprecipitation technique with the help of ultrasonic waves and chosen as support for 15 ​wt% Ni and Co active phases. Examination of the BET surface properties of the catalysts showed an increase in surface area in the range of 54–82 ​m²/g and 73–85 ​m²/g with an increasing Fe loading for Ni and Co catalysts, respectively. Among the Ni-based catalysts, the 15Ni/10FeMgAl₂O₄ specimen exhibited the best performance (with a 73.31 ​% CO₂ conversion and 95.61 ​% selectivity rate) and remarkable lifetime during 10 ​h at 400 ​°C due to the better reducibility and the increase in hydrogen consumption. However, a rise in Fe amount to 15 ​wt% led to a reduction in the CO₂ conversion to 34.43 ​%. The catalytic outcomes also demonstrated that the presence of Fe in Co/MgAl₂O₄ catalysts negatively affects catalytic performance. The unpromoted Co/MgAl₂O₄ sample demonstrated the best performance, achieving a conversion rate of 52.41 ​% at 350 ​°C.