La-Based Perovskites as Oxygen-Exchange Redox Materials for Solar Syngas Production
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La-Based Perovskites as Oxygen-Exchange Redox Materials for Solar Syngas Production Rahul R. Bhosale, Anand Kumar, Anchu Ashok, Parag Sutar, Gorakshnath Takalkar, Majeda Khraisheh, Fares AlMomani, Ujjal Ghosh Department of Chemical Engineering, Qatar University, Doha, Qatar. ABSTRACT This contribution reports the synthesis and characterization of La-based perovskites which can be used for the production of syngas via solar thermochemical splitting of H2O/CO2. The La-based perovskites were synthesized using a solution combustion synthesis approach. The derived perovskites were analyzed using powder X-ray diffractometer (PXRD), BET surface area analyzer (BET), and scanning/transmission electron microscope (SEM/TEM). The results associated with the synthesis and characterization of La-based perovskites is reported in detail. INTRODUCTION The energy consumption of the world today is around 15TW and it is expected that it will raise upto 30TW by the year 2050. In addition to this, due to the excessive utilization of fossil fuels (for the production of required energy), the concentration of CO2 in the environment increases rapidly [1-3]. The production of syngas (which can be used as a precursor for the production of liquid transportation fuel) by using H2O, CO2, and solar energy provides a promising path to solve the issues associated with the utilization of fossil fuels and increase in the CO2 concentration. Direct production of syngas via thermolysis of H2O and CO2 is possible, however it needs a very high temperature and chances of forming a gaseous explosive mixture of H2 and O2 is also very high. Utilization of solar driven metal oxide based thermochemical H2O and CO2 splitting cycle reduces the requirement of higher temperatures and avoids the formation of explosive gas mixture. The two-steps involved in this cycle are represented as: 1 ππππ₯ππππ§ππ β ππππππ’πππ + π2 (1) 2 ππππππ’πππ + π»2 π/πΆπ2 β ππππ₯ππππ§ππ + π»2 /πΆπ (2) In previous investigations, two types of metal oxide based redox systems were examined for the solar thermochemical H2O and CO2 splitting, namely: 1) volatile metal oxide pairs such as ZnO/Zn [4,5], or SnO2/SnO [6-8] and 2) non-volatile MO pairs such as Fe3O4/FeO [9-11], ferrites and ceria based redox oxides [12-22]. Among the many MOs investigated so far for their application in STCs, research has been focused in recent years towards non-stoichiometric ceria based redox materials consisting of the fluorite structure. These materials are particularly attractive because they involve minimum number of steps and can avoid the recombination reactions and irreversibility associated with other volatile MO based redox cycles such as ZnO/Zn or SnO2/SnO. In addition, non-stoichiometric ceria based redox materials shows fast redox kinetics; however, higher operating temperatures (β₯ 1500Β°C) are necessary for the ceria fluorite structure to sustain large oxygen deficiency and to achieve a reasonable fuel production. The solar thermochemical community strongly believes that in order for this technology to be cost co
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