Boosting biogas chemical looping reforming via transition metal-doped LaFeO3 Perovskites: Activity Promotion and mechanistic insights

Biogas utilization through chemical looping reforming (CLR) offers a promising strategy for renewable syngas production. However, pristine LaFeO3 suffers from insufficient lattice oxygen reactivity, limiting methane conversion. Herein, a series of transition metal (Ni, Co, Cr, Mn, Mo, Cu) doped LaFeO3 perovskites were developed to enhance the redox performance for biogas CLR. Structural characterizations confirm that B-site substitution preserves the perovskite matrix while tuning Fe-O bonding and oxygen vacancy concentration. These changes strongly influence lattice oxygen participation in CH4/CO2 conversion. Among the perovskites, Ni doping significantly improves lattice oxygen mobility and methane activation. The optimized LF-6Ni exhibits the highest initial cycle performance, achieving a syngas yield of 213 mmol/g and CH4 conversion above 97%. Under repeated redox operation, the same material maintains syngas yields above 174 mmol/g, with CH4 conversion remaining near 80% after 30 cycles, demonstrating good cycling durability. This study reveals a qualitative composition-structure-activity relationship and identifies LF-6Ni as a highly efficient and stable oxygen carrier for biogas upgrading, providing a useful basis for designing oxygen carriers for efficient CH4/CO2 co-conversion in biogas chemical looping reforming.