Catalytic performance and mechanism of A-site vacancy deficient perovskite catalyst over tar cracking during biomass pyrolysis

Tar from biomass pyrolysis is an urgent problem to be solved for the large utilization of biomass pyrolysis technology. This work focuses on the activity evaluation of perovskite catalysts with various strontium content to crack biomass tar at 700 °C. Cracking results show that the catalytic performance of Sr-doped catalysts are better than that of undoped one and the participation of perovskite catalysts increases the yield of gas by promoting the tar conversion. La0.8Sr0.2Ni0.8Fe0.2O3 (LS2) shows the highest gas yield of 606.7 mL/gbio and syngas yield of 475.0 mL/gbio. Characterization results by various advanced technologies show that Sr-doped perovskites have higher redox capacity, oxygen mobility, and better surface area and pore volume in favor of gas adsorption and conversion. A possible tar catalytic cracking mechanism is proposed. Oxygen vacancy-induced redox reaction and metal sites are the main effective mechanism. This work would offer a feasible exploration into the application of perovskite-type catalysts on biomass tar conversion.