Oxygen-vacancy-engineered Pr-Ce-Fe perovskite on calcined dolomite for tar reforming and H2-rich syngas production during staged biomass gasification

The global transition toward low carbon energy systems has intensified the demand for renewable H 2 and cleaner syngas production. Biomass steam gasification is a promising route, but tar formation and catalyst deactivation still limit its practical application. Herein, Pr 1– x Ce x FeO 3 supported on calcined dolomite was developed for staged biomass steam gasification to couple H 2 production with tar reforming. Statistical screening identifies gasification temperature, Ce substitution level, and steam flow rate as the dominant factors controlling H 2 formation. Under single-factor conditions, Pr 0.6 Ce 0.4 FeO 3 /CD shows the best performance, giving 44.33 vol% H 2 , a total gas yield of 1.51 Nm 3 /kg biomass, a syngas yield of 1.10 Nm 3 /kg biomass, and a syngas fraction of 72.77 vol%. Tar conversion is optimal near 850 °C, where the dry tar yield decreases to 22.75 g/kg biomass, while heavy polycyclic aromatics and >C13 compounds account for 0.79% and 4.14% of the total gas chromatography-mass spectrometry (GC-MS) peak area, respectively. Response surface optimization gives an optimum at 810 °C, x = 0.4, and a steam flow rate of 1.2 mL/min, with an experimental H 2 fraction of 46.22 vol%. Structural and surface analyses indicate that moderate Ce substitution preserves the perovskite framework while regulating defect formation, surface oxygen species, and Fe/Ce/Pr redox behavior. Cycling deactivation is mainly associated with carbonaceous deposits, Fe migration, CaO carbonation, and structural densification. This work provides a feasible perovskite dolomite strategy for integrated tar reforming and production of syngas rich in H 2 from biomass.