第二届中国化学链会议

Layered double hydroxide (LDH) is a powerful self-template to synthesize high performance oxygen carriers for chemical looping processes. Since active and support species can be easily combined from the M²⁺ and M³⁺ metal layers in LDH structure, in this work, doping M²⁺ metal (M = Ni, Cu, Mn, Ca) was applied to improve the redox reactivity of the Mg-Fe-Al-O oxygen carriers. From XRD patterns, M doped LDH derived Mg-Fe-Al-O oxygen carriers mainly formed spinel phase and MgO phase (except for Ca²⁺, formed CaFe₂O₅ instead). SEM images showed that the Ni and Cu doped oxygen carriers form clear layered and classic flower-grain morphologies, respectively, while the Mn and Ca doped oxygen carriers are both appeared a granular morphology. Ni doped oxygen carriers exhibited an oxygen storage capacity of 20 mol[O]·kgFe+Ni-1 while that of other M doped oxygen carriers were around 10 mol[O]·kgFe+Ni-1. After 20 CH₄-CO₂ cycles, Ni doped oxygen carriers performed with 7 mol[CO]·kgFe+Ni-1·min-1 CO space time yield during CO₂ oxidation half-cycle. This might be ascribed to that: (i) Ni catalyzes methane to decompose into carbon, (ii) CO₂ eliminates the carbon deposition formed during CH₄ reforming half-cycle.

化学链重整,化学链二氧化碳还原,LDH衍生氧载体,原位掺杂