Introducing K to\nRegulate the Electronic Structure\nof Perovskite-Type Oxide for the Efficient Reaction of Coke and Steam

The coking process hinders the long-term stable production\nof ethylene,\nso the rational design of the catalyst structure to achieve efficient\nin situ coke removal is the focus of research. Herein, a synthesis\nmethod for the controllable preparation of the perovskite molecular\nstructure (A<sub>2</sub>B<sub>2</sub>O<sub>6</sub>, R-P, ABO<sub>3</sub>) was proposed, and the relationship between the perovskite structure\nand coke removal performance was revealed. DFT and experimental results\njointly proved that the O 2p-band of the double perovskite shifts\nupward to the Fermi level, thus promoting the formation of free radical\nspecies. Double perovskite mainly promoted the contact reaction between\nthe adsorbed hydroxyl radical and graphite carbon interface and also\nstrengthened the gas–solid reaction between the free hydroxyl\nradical and graphite carbon, thus improving the conversion rate of\ncoke. In the presence of double perovskite LaKSr<sub>0.17</sub>Fe<sub>1.5</sub>O<sub>6</sub>, the maximum coke conversion rate is 100%.\nThis method provides a theoretical basis for the synthesis of heterogeneous\ncatalysts.