Enhancement of Hydrogen-Rich Syngas Production Using a Robust Sr_0.75Ba_0.25FeO_3-δ Oxygen Carrier for Biomass Chemical...

Chemical looping gasification is a promising technology for transforming biomass to value-added hydrogen-rich syngas; however, the existing oxygen carriers face the challenges of low catalytic activity and stability, hindering their conversion performance at a wide range of biomass fuels and reaction temperatures. Herein, Sr_0.75Ba_0.25FeO_3-δ was synthesized and applied to hydrogen-rich syngas production, and experiments were conducted in a fixed-bed reactor. The effects of ratios of oxygen carrier and biomass, temperatures, and biomass types on cyclic performance were investigated. Results revealed that the H₂ concentration and H₂ yield could reach ~80% and ~13 mmol g^-1 for pine sawdust, ~85% and ~4 mmol g^-1 for cellulose, and ~70% and ~25 mmol g^-1 for lignin at 850°C. At 750-900°C, the H₂ concentration stabilized at above 60%. In addition, Sr_0.75Ba_0.25FeO_3-δ maintained a H₂ yield of 16 mmol g^-1 after multiple cycles. Compared with traditional oxygen carriers, Sr_0.75Ba_0.25FeO_3-δ shows at least 30% enhancement in H₂ production rate. The outperformed H₂ production is attributed to the high lattice oxygen activity and catalytic ability. This work demonstrated that Sr_0.75Ba_0.25FeO_3-δ is a promising oxygen carrier candidate for biomass chemical looping gasification with fuel adaptability, temperature flexibility, and catalytic stability.