Promotional effects of Ce on Fe-CeγAl₂O₃ oxygen carriers for low-temperature chemical looping hydrogen production

Innovative methods for producing hydrogen, like chemical looping hydrogen production (CLHP), are being explored to achieve sustainable hydrogen production and increase efficiency. This study investigates the modification of Al₂O₃ with ceria (CeO₂) to enhance the performance of iron-based oxygen carriers for CLHP. The research demonstrates that incorporating ceria not only enhanced surface area but also influenced metal distribution within the support, providing more active sites and reducing the reduction temperature of Fe₂O₃ due to diminished metal-support interaction. X-ray diffraction results confirm that ceria inhibits iron aluminate formation. The structural stability of gamma-alumina (γ-Al₂O₃) is maintained, preventing detrimental phase transitions. Adding Ce significantly lowers the desorption energy for both γ-Al₂O₃ and α-Al₂O₃ supports. The Fe-CeγAl oxygen carrier shows the highest methane conversion at 77 % in 50 s, while Fe-CeαAl achieves the best hydrogen production at 0.57 mmol/g. These findings highlight the potential of ceria-modified supports to improve the efficiency and effectiveness of oxygen carriers in hydrogen production.