| A promising alternative for oxygen production – application of air-operating <i>R</i>MnO<sub>3+δ</sub> oxides in low-temperature TSA Kacper Cichy1; Konrad Swierczek2; Juliusz Dąbrowa3; 1AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, Krakow, Poland; 2AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF ENERGY AND FUELS, Krakow, Poland; 3AGH UNIVERSITY OF SCIENCE AND TECHNOLOGY, FACULTY OF MATERIALS SCIENCE AND CERAMICS, Kraków, Poland; PAPER: 205/AdvancedMaterials/Regular (Oral) SCHEDULED: 16:45/Tue. 29 Nov. 2022/Saitong ABSTRACT: The oxygen demand for medical and industrial needs grows over 6% annually from 2015, and it is estimated that the oxygen market will grow from $27.7 billion in 2019 to even $ 36.5 billion in 2030 [1]. According to The Business Research Company, this growth will be also driven by COVID-19 and the medical needs it imposes [1].<br /> Today, most of the oxygen produced for large-scale industry needs is obtained by cryogenic distillation, which due to the high energy consumption of the liquefaction of gases from the air, is an expensive method [2]. A promising alternative to the cryogenic oxygen production technology is air separation by temperature-swing adsorption (TSA) where so-called oxygen storage materials (OSM) are used. OSMs can reversibly exchange a significant amount of oxygen between their structure and atmosphere.<br /> In the last 2 decades, renewed interest in <i>R</i>MnO<sub>3+δ</sub> oxides appeared, in terms of their application as OSMs. Their main advantage (contrary to other groups of OSMs, [3]) is the ability to work in the temperature-swing mode at temperatures as low as 200-300 °C, which is promising from both, economical and construction points of view. However, until now most of those materials operated effectively only in pure O<sub>2</sub> atmosphere, which is not applicable for oxygen production.<br /> A significant breakthrough has come with the results of the recent research, as it was possible to design <i>R</i>MnO<sub>3+δ</sub> materials able to operate in air practically as effectively as in O<sub>2</sub> atmosphere [4]. Also, some general rules were established in terms of designing such air-operating OSMs, like dependence of oxygen storage capacity (OSC) on ionic radius of R.<br /> Nd-substituted Y<sub>1-x</sub>Nd<sub>x</sub>MnO<sub>3+δ</sub> materials described in this work were synthesized via sol-gel auto-combustion method followed by several variations of annealing at elevated temperatures in different atmospheres. Crystal structure and phase composition of prepared powders were examined by means of X-ray diffractometry (XRD). Oxygen storage performance was evaluated using thermogravimetry. Structure and composition of oxidized samples were also investigated by XRD. Morphology of powders was examined by scanning electron microscopy.<br /> It was established that proper modification of the preparation route of the Nd-substituted Y<sub>1-x</sub>Nd<sub>x</sub>MnO<sub>3+δ</sub> can increase the OSC more than twice and greatly improve the rate of redox reactions. The laboratory-scale apparatus for oxygen separation from air via TSA was designed and constructed. Equipment was tested using the YMnO3+δ-based materials developed in this work. References: [1] The Business Research Company, Oxygen Global Market Opportunities And Strategies (2020)<br />[2] O. Parkkima, YBaCo4O<sub>7+δ</sub> and YMnO<sub>3+δ</sub> Based Oxygen-Storage Materials, PhD Thesis, Aalto University, Aalto, Finland, 2014<br />[3] T. Motohashi, Y. Hirano, Y. Masubuchi, K. Oshima, T. Setoyama, S. Kikkawa, Chem. Mater. 25 (2013) 372-377<br />[4] K. Cichy, K. Świerczek, K. Jarosz, A. Klimkowicz, M. Marzec, M. Gajewska, B. Dabrowski, Acta Mater. 205 (2021) 116544 |
