Fluidizable NiO/Ce-γAl2O3 Oxygen Carrier for Chemical Looping Combustion

This communication presents the effects of Ce modification on NiO/Ce-γAl2O3 oxygen carrier for chemical-looping combustion (CLC). The NiO/Ce-γAl2O3 samples are prepared by an incipient wetness technique using successive metal loading. The reduction characteristics of the prepared oxygen carriers are evaluated in repeated temperature-programmed reduction/oxidation cycles. The results show that the presence of Ce minimizes metal/support interaction and improves the reducibility and oxygen carrying capacity of the oxygen carriers. As a result, almost 94 wt % nickel oxides on Ce-γAl2O3 is reduced as opposed to only 77 wt % of nickel oxides on bare γAl2O3. The presence of Ce also provides stable reduction performance over repeated oxidation/reduction cycles, which is essential for a CLC process. The sustained reducibility of the samples is mainly due to the absence of agglomeration and the formation of easily reducible nickel oxide species instead of nickel aluminate. The EDX mapping of the oxygen carrier show...