A-site disubstituted of La1−xSrxNi0.8Fe0.2O3 perovskite on coal pyrolysis volatiles catalytic cracking: Activity and reaction mechanism

Abstract

This work focuses on the result of strontium doping on La1−xSrxNi0.8Fe0.2O3 catalytic cracking of coal tar in the COREX process. The results show that Sr doping significantly affected the catalytic performance of perovskite. O2-Temperature programmed desorption (O2-TPD) and X-ray photoelectron spectroscopy (XPS) results show that La0.8Sr0.2Ni0.8Fe0.2O3 (Sr 0.2) has more active oxygen species and higher oxygen mobility. The performance of Sr-doped catalysts is higher than that of LaNi0.8Fe0.2O3, producing less tar and carbon deposition. Moreover, Sr 0.2 exhibited the highest gas yield of 34.6 mmol/gcoal, H2 yield of 27.5 mmol/gcoal, 100% tar conversion rate, and the lowest carbon deposition of 19.4 mg/(g·h). Tar cracking mechanism was proposed by characterization results. The perovskite could serve as a bridge for oxygen migration and simultaneous oxygen supplementation, thus sustaining catalyst activity and durability. The appropriate amount of Sr doping perovskite is favorable to high catalytic activity and anti-carbon deposition at high temperatures. This work could provide some referential value for the highly-efficient cracking of tar.