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 La 1- x Sr x FeO 3 (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. Perovskite LaFeO 3 is doped with s-block metal strontium (Sr) to regulated band gap of perovskite and move the O 2 p -band center up relative Fermi level, which enhances the generation of free ·OH radicals and the efficient in-situ conversion of coke. [Display omitted] [ABSTRACT FROM AUTHOR]