Coke formation and utilization during coke oven gas reforming–CO2 splitting cycles over spherical SrFeO3 pellets for syngas and CO production

Spherical SrFeO 3 pellets are used for effective syngas and CO production during coke oven gas reforming (COGR) and CO 2 splitting (CS), exhibiting a high CH 4 oxidation activity and suppressing reduction by H 2 and CO during methane reforming (MR). Above 850 °C, MR produces H 2 -rich syngas through simultaneous reduction and CH 4 decomposition reactions. For sequential CS, CO production is amplified owing to the co-occurrence of CO 2 splitting and reverse Boudouard reactions. The redox reaction time is optimized to realize MR–CS cycling with a high redox stability and coke utilization efficiency. From the third MR–CS cycle onward, the reoxidation percentage exceeds 96.4 %, consistent with crystal structure evolution. Amorphous carbon is deposited on SrFeO 3− δ via the decomposition of CH 4 during MR, and the content of this carbon remains constant after the 10th MR–CS cycle because of its high reactivity toward CO 2 . Over 10 COGR–CS cycles, superior coke utilization due to the occurrence of the reverse Boudouard reaction during COGR results in stable syngas and CO production from the second cycle onward. • H 2 /syngas production via coke oven gas reforming (COGR)–CO 2 splitting (CS) is studied. • COGR–CS is promoted by SrFeO 3 , and the redox behavior of this mediator is examined. • The reaction parameters are optimized to achieve stable and efficient COGR–CS cycling. • Superior coke utilization is achieved & explained, contributing to cycling stability. • Role of oxygen vacancies in SrFeO 3 in determining COGR–CS performance is revealed.