Use of a high-entropy oxide as an oxygen carrier for chemical looping

• Published in: Energy (Oxford) Vol. 298; p. 131307
• Main Authors: Adánez-Rubio, Iñaki, Izquierdo, María T., Brorsson, Joakim, Mei, Daofeng, Mattisson, Tobias, Adánez, Juan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2024
• Subjects: Chemical looping; High entropy oxygen carriers; Oxygen uncoupling; Syngas; High entropy oxygen carriers; Oxygen uncoupling; Chemical looping; Syngas
• ISSN: 0360-5442; 1873-6785
• DOI: 10.1016/j.energy.2024.131307

One mixed oxide with 5 cations in equimolar proportions in the sublattice, to fulfil high-entropy oxide (HEO) criteria, has been developed and investigated as oxygen carrier for chemical looping combustion processes. As far as we know, nobody has explored this class of material for chemical looping combustion. Material is prepared by direct mixing of five metal oxides (CuO, Mn2O3, Fe2O3, TiO2, MgO), followed by calcination at 1000, 1100 and 1200 °C for 6 h in air. XRD characterization provides strong evidence that the synthesized oxygen carriers possess the hallmark properties of HEO, and SEM-EDX analysis shows an overall homogeneous metal distribution. Materials have one main cubic phase with the empirical formula MnCuMgFeTiO7, dominating under all conditions. One of the key objectives of this study is achieved, reduce chemical stress during redox cycles. Oxygen transfer capability is investigated by thermogravimetric analysis and batch fluidized bed reactor experiments for different fuels and atmospheres. Mass-based oxygen transport capacities for lattice oxygen and oxygen uncoupling are around 5.5 wt% and 1.1 wt%, respectively. This work opens up a new dimension for the future preparation of oxygen carriers for chemical looping processes, since the vast compositional space of HEO provides opportunities to tune both chemical and physical characteristics. [Display omitted] •This work demonstrates the use of a High Entropy Oxygen Carrier for Chemical Looping.•Five metal oxides in equimolar proportions (CuO, Mn2O3, Fe2O3, TiO2, MgO) were used.•Characterization provided strong support that the OC has high entropy oxide properties.•The material had one main, cubic, phase, with the empirical formula MnCuMgFeTiO7.•Oxygen transport capacity for Chemical Looping (5.5 wt%) and CLOU (1.1 wt%) were obtained.