(329b) Solar Thermochemical CO2 Splitting Using CexZn1-XO2 Derived Via Co-Precipitation Method

Thermochemical splitting of H₂O and CO₂ generates a mixture of CO and H₂ i.e. syngas which can be used for the production of storable and transportable liquid hydrocarbon fuels via Fischer-Tropsch (FT) process. This offers a renewable, environment friendly and long-term solution for future energy demand with CO₂ mitigation. The MO-based two-step solar thermochemical fuel production process involves successive reduction and re-oxidation of the metal oxides resulting into production of O₂ and H₂/syngas in separate steps. Among the various metal oxides investigated until now, ceria based redox materials are considered as a very good option due to their high thermal stability and faster kinetics. Recently we have explored transition metal doped ceria materials (Ce_0.9M_0.1O₂, where, M = transition metal dopants) towards thermochemical splitting of CO₂. The obtained results indicate that the doping of Zn in the ceria fluorite crystal structure is very beneficial towards achieving higher levels of O₂ release and CO production. In this study, we have synthesized Ce_xZn_1-xO₂ (by varying x in the range of 0 to 0.5) using co-precipitation of hydroxide method. The physical properties of the Ce_xZn_1-xO₂ materials are analyzed using powder X-ray diffraction, BET surface area analyzer, scanning and transmission electron microscope, and energy dispersive spectroscope. The synthesized Ce_xZn_1-xO₂ materials are further examined in multiple thermochemical CO₂ splitting cycles using a high temperature TGA. The gases evolved are analyzed using an online GC-MS set-up. Based on the variations in the mass loss/gain profiles and the GC-MS results, the amounts of O₂ released and CO produced by all Ce_xZn_1-xO₂ materials investigated in this study are calculated. The detailed analysis of the synthesis, characterization, and CO2 splitting reactions will be discussed in detail.