Improvement of reduction and oxidation performance of MMgOx (M=Fe, Co, Ni, and Cu) particles for chemical looping combustion

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The objective of this study was to use Mg to improve the performance in chemical looping combustion. Oxygen carrier particles were synthesized in which Mg was doped into the M-sites with Fe, Co, Ni, and Cu to produce FeaMgbOx, CoaMgbOx, NiaMgbOx, and CuaMgbOx, respectively, with M/Mg ratios ranging from 1.5 to 3.0. The structure and properties of the prepared samples were characterized using XRD, SEM, CH<SUB>4</SUB>-/CO-TPD, XPS, and TGA. The XRD results explore that the Fe2Mg1Ox sample has a pure cubic structure of Fe<SUB>2</SUB>MgO<SUB>4</SUB>, whereas the Co2Mg1Ox and Ni2Mg1Ox samples exist as a solid solution. Nevertheless, the mixed compound formation of orthorhombic structure of Cu<SUB>2</SUB>MgO<SUB>3</SUB> and cubic structure of MgO has been observed in Cu2Mg1Ox. The CH<SUB>4</SUB> absorption is the highest on the Cu2Mg1Ox sample according to the CH<SUB>4</SUB>-TPD results. The CO-TPD and H<SUB>2</SUB>–TPR results showed that the adsorption of the Cu and Mg complex metal oxide is higher than that of the pure metal oxide. The oxygen carrier capacity of the samples was studied by isothermal H<SUB>2</SUB> (FR)/air (AR) and CH<SUB>4</SUB> (FR)/air (AR) redox cycle experiments at 850°C using TGA. The promising results obtained from chemical looping combustion indicate that the CuaMgbOx samples are potentially useful for CLC in H<SUB>2</SUB> and CH<SUB>4</SUB> atmospheres.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Redox performance for MaMgbOx (M=Fe, Co, Ni, and Cu) was investigated in detail. </LI> <LI> The highest redox performance (15.29wt%) was observed for Cu2.0Mg1.0Ox. </LI> <LI> The Cu2.0Mg1.0Ox sample was stable up to 10 reaction cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Redox reaction on the M2.0Mg1.0Ox (M=Fe, Co, Ni, and Cu) for the chemical looping combustion.</P> <P>[DISPLAY OMISSION]</P>