Chemical looping dry reforming of methane(CL-DRM)is a process simultaneously utilizing two greenhouse gases,carbon diox-ide,and methane,and converting them into syngas that can be used for Fischer-Tropsch synthesis.A series of(Ni/CeO2)/ABO3(Per-ovskite-type)composite oxygen carriers were prepared by sol-gel and impregnation methods and the effects of Ni/CeO2 loading on the ox-ygen storage performance of perovsokite were investigated.The effects of different Ni/CeO2 loadings on the activity of La0.8Sr0.2FeO3 per-ovskites were explored and the cycling stability of the oxygen carriers was analyzed.It was found that the interaction of CeO2 with the carri-er La0.8Sr0.2FeO3 favors the formation of oxygen vacancies in perovsokite,which enhances their oxygen mobility.The loading of Ni/CeO2 improved the oxygen storage performance of the oxygen carrier,lowering the initial reaction temperature and enhancing the reaction activi-ty,however,a high loading would lead to methane cracking to form carbon deposits.The(Ni/CeO2)/La0.8Sr0.2FeO3 composite oxy-gen carrier reached 82％methane conversion with a 2.1 H2/CO molar ratio when the Ni/CeO2 loading was 20％.Furthermore,the catalyst remained stable after 30 cycles and showed excellent cycling stability performance.In addition,CeO2 particle size can significantly affect the dispersion of the Ni phase.The reduction of CeO2 particle size enhances interfacial interaction with metal Ni,improves oxygen carrier reactivity,and reduces methane cracking.Modulating CeO2 particle size enabled the oxygen carrier to achieve over 87％CH4 conversion,over 90％CO selectivity,and a H2/CO ratio of 2.18,close to the ideal value of 2.0.The strategy of preparing composite oxygen carriers with perovsokite-anchored active species offers an effective approach for high performance in chemical looping dry reforming.Additionally,the preparation of highly active and stable composite metal oxide oxygen carriers serves as a reference for oxygen storage catalytic materials in related fields.
chemical loopingreformingcarbon dioxideoxygen carrieroxygen vacancy
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