Phase interactions in Mg-Ni-Al-O oxygen carriers for chemical looping applications

Chemical looping combustion offers a solution to achieve carbon capture with minimal energy penalty and significantly reduced NO_x formation. The design and synthesis of oxygen carriers play an important role in the advancement of chemical looping combustion. In this investigation, Mg-Ni-Al-O oxygen carriers were synthesised using layered double hydroxides (LDH) as precursors, which facilitate molecular level dispersion of cations in the resulting oxide composites. The behaviour of the synthesised oxygen carriers over 100 chemical looping cycles was studied. The results confirmed the presence of two solid solutions systems: MgO-NiO and MgAl₂O₄-NiAl₂O₄, the compositions of which changed over cycles and determined the performance of the oxygen carriers.