The effect of strontium doping in La_1-xSr_xNi_0.8Fe_0.2O₃ perovskite catalyst was investigated for tar catalytic cracking in the COREX process at 700 °C. O₂-Temperature programmed desorption (O₂-TPD) and X-ray photoelectron spectroscopy (XPS) results show that La_0.8Sr_0.2Ni_0.8Fe_0.2O₃ (Sr 0.2) has more active oxygen species and higher oxygen mobility. The performance of Sr-doped catalysts is higher than LaNi_0.8Fe_0.2O₃, producing less tar and carbon deposition. Moreover, Sr 0.2 exhibited the highest gas yield of 34.6 mmol/g_coal, H₂ yield,of 27.5 mmol/g_coal, 100% tar removal rate, and the lowest carbon deposition of 19.4 mg/(g·h). Prediction of the reaction mechanism for catalytic cracking is proposed based on the XPS and O₂-TPD results. The perovskite serving as a bridge for oxygen migration and simultaneous oxygen supplementation sustains catalyst activity and durability. Coal tar can be converted into more gas by oxygen supply from catalysts. The appropriate amount of Sr in the perovskite is favorable to high catalytic activity and anti-carbon deposition at high temperatures. This work could provide some guidance for the highly efficient cracking of tar.
 

perovskite catalyst, Sr doping, coal tar, reaction mechanism