Carbon precursor engineering in chemical looping co-gasification of microalgae-lignocellulosic biomass enabled by Ce-doped perovskite oxygen carriers

Biomass chemical looping co-gasification (BCLCG) offers a promising route for converting renewable biomass into controllable gaseous carbon precursors, though precise regulation of carbon distribution remains challenging. Here, we propose a carbon precursor engineering strategy via co-gasification of pine sawdust (PS) and Chlorella (CH) using Ce-doped LaFeO 3 (LFO) perovskite oxygen carriers. Ce incorporation significantly enhances lattice oxygen mobility, oxygen vacancy concentration, and structural stability. Among the samples, La 0.7 Ce 0.3 FeO 3 (L 0.7 C 0.3 FO) exhibits optimal redox performance, maintaining a high specific surface area (4.13 m 2 /g) and stable mesoporous structure after reaction while suppressing sintering-induced pore collapse. A pronounced synergistic effect is observed during PS-CH co-gasification: hydrogen-rich volatiles and intrinsic alkali/alkaline earth metals from CH promote tar cracking and char conversion, facilitating carbon redistribution toward gaseous products. At the optimal blending ratio (PS/CH = 1:2), the carbon precursor formation (CPF = CO + CH 4  + C 2 -C 4 ) reaches 0.362 Nm 3 /kg with a total gas yield of 1.268 Nm 3 /kg, and carbon utilization efficiency (CUE) reaches 67.6%. Process optimization reveals that carbon precursor formation is governed by lattice oxygen supply, steam participation, and thermal conditions. The optimal conditions (900 °C, oxygen carrier-to-biomass ratio of 1.0, steam flow rate of 0.3 mL/min) enhance CUE. This work reinterprets BCLCG as a carbon precursor engineering platform rather than conventional syngas production. The integration of Ce-doped perovskite oxygen carriers with multi-source biomass enables precise carbon distribution regulation and provides a viable pathway for efficient biomass conversion into carbon-oriented gaseous products.