Precise flame-synthesized oxygen carriers for enhanced syngas and hydrogen production

Flame synthesis of oxygen carriers (OCs) with specific functions remains challenging. In this study, the brownmillerite Ca 2 Fe 2 O 5 OCs properties are precisely regulated by adjusting the type of ester solvent, oxygen concentration, and carrier gas flow rate during diffusion flame synthesis. The utilization of flame-synthesized OCs in the chemical looping reforming coupled with water splitting (CLRWS) to produce syngas and hydrogen has been elucidated. At a high oxygen concentration (60 % O 2 ), OCs synthesized using propyl propionate solvent aerosol flame, yielding 33 nm polycrystalline particles, exhibit exceptional performance with an 82.6 % fuel conversion rate, 3.09 Nm 3 /L syngas yield, and 11.16 mmol/g OC hydrogen yield at 850 °C, surpassing classical methods. The high reduction capacity and lattice oxygen activity can be attributed to the multiple exposed crystal faces and active sites. This study aimed at regulating and producing OCs with excellent activity for biomass utilization and catalysis.