Band gap regulation of LaFeO3 via doping Sr for efficient conversion of coke and steam

Coking is bottleneck problem during steam cracking processes, so strategies for online catalytic conversion of coke are vitally important for ethylene production. In this work, a method for regulating the band bap of perovskites to enhance hydroxyl radical generation is proposed to promote the catalytic conversion of coke. A series of ternary La1-xSrxFeO3 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) perovskites were successfully prepared by sol-gel method. Experimental and DFT calculations show that Sr doped at A sites facilitates a reduction in the band gap and the promotion of electronic transitions in the perovskites. Moreover, water molecule adsorption, decomposition, and intermediate transition state desorption are improved. Using 10 wt.% LSF-0.6 catalyst, a water flow rate of 0.167 mL/min, reaction temperature of 900 °C, and reaction time of 120 min, a coke conversion rate of 85.56% is achieved. This work provides a theoretical basis for in-situ high-efficiency coke removal.