Effect of Nickel and Cobalt Doping on the Redox Performance of SrFeO3-& delta; toward Chemical Looping Dry Reforming of Methane

Thelow-content metal dopant in the oxides has a beneficial effecton the redox performance of these materials. However, the role ofdopants remains elusive. Herein, SrFeO3-& delta; perovskiteswith low-content Ni or Co were investigated as oxygen carriers (OCs)for chemical looping dry reforming of methane. Compared with pristineSrFeO(3-& delta;), the doped ones show an acceleratedtransition phase in the reduction step. As a result, doping causesan increase in both methane conversion and amount of lattice oxygenconsumption. Among the OCs, SFO/01Ni with a Ni/Sr mole ratio of 0.001exhibits superior performance. The possible mechanism for the optimalSFO/01Ni is linked to the synergistic effect between the enhancedmigration of lattice oxygen and the improved catalytic performanceresulted from the reduced metal particles and anchored Ni particles.In 20 tailored redox cycles at 900 & DEG;C, the productivity of H-2 and CO over SFO/01Ni is always twice as high as that overSFO and SFO/01Co, suggesting that SFO/01Ni may sustain the periodicallystructural change in the bulk under the harsh reaction conditions.These findings advance the understanding of the role of non-nobledopants in methane oxidation over perovskites and may greatly inspirethe rational OC design and exploration for chemical looping reforming.