Synthesis and characterization of cerium promoted Ni/SBA-16 oxygen carrier in cyclic chemical looping steam methane reforming

- The effect of cerium on the performance of OC was determined in CL-SMR process.
- Effects of Ni loading, Ce loading and reaction temperature were studied.
- Cerium can improve the reactivity of oxygen carrier (OC) in CL-SMR.
- Ce improved the dispersion of Ni particles with smaller sizes on the support.
- Metal agglomeration and coke formation were inhibited by using Ce in Ni/S16 OC.
- 20Ni-11.6Ce/S16 oxygen carrier exhibited high stability and activity in CL-SMR.

Chemical-looping steam methane reforming (CL-SMR) is based on oxidation-reduction cycles through a solid-gas reaction with an oxygen carrier (OC) for producing high purity hydrogen or synthesis gas. In this study, Ce promoted Ni-based OC was synthesized via co-impregnation method and applied in this process. The presence of CeO2 nanoparticles in the framework of nickel oxide doped SBA-16 oxygen carrier could significantly improve the uniformity and distribution of nickel oxide nanoparticles duo to the restrictional influence of the SBA-16 framework and the strong interaction of nickel and cerium. The reaction temperature (500-750 °C), Ce loading percentage (3.9-23.3 wt. %) and Ni loading percentage (10-30 wt. %) were studied in order to investigate and optimize the catalyst structure and process temperature with maximizing the average CH4 conversion and H2 production yield in this process. The synthesized oxygen carriers were characterized by X-ray powder diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. The redox results revealed that 20Ni-11.6Ce/S16 oxygen carrier had the high catalytic activity of about 100% average CH4 conversion and 86.98% H2 production yield at reduction temperature of 700 °C.

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