A-site engineering of iron-based perovskites for syngas production via biogas chemical looping reforming

Chemical looping reforming (CLR) offers a promising route for efficient biogas conversion, yet the development of robust oxygen carriers remains critical. This study systematically investigates three iron-based perovskite oxygen carriers-LaFeO3, SrFeO3, and BaFeO3-for biogas CLR. Through combined experimental and DFT approaches, we elucidate the role of A-site cations (La3+, Sr2+, Ba2+) in modulating redox activity, structural stability, and CH4 adsorption energy. LaFeO3 exhibits superior reducibility (onset reduction at 560 °C), high oxygen vacancy concentration (65.95 %), and outstanding syngas yield (61.96 mmol/g at 850 °C), attributed to its robust perovskite framework. In contrast, BaFeO3 suffers from phase decomposition, while SrFeO3 shows intermediate reactivity. Cyclic tests confirm LaFeO3's stability over 10 redox cycles. DFT reveals stronger CH4 adsorption on LaFeO3, facilitating C-H activation. The presence of CO2 in biogas can promptly react with carbon deposits generated from CH4 cracking, preventing the coverage of the oxygen carrier surface by carbon deposits, which would otherwise block the reaction between biogas and the oxygen carrier. This work provides mechanism insights into perovskite-based oxygen carrier design, advancing sustainable biogas to syngas technologies for clean energy applications.