(684e) Perovskite Oxides for Low Temperature Carbon Dioxide Conversion Towards Hydrocarbon Generation
Mixed metal oxides like perovskite oxides (ABO3) are the main vehicles of conversion of CO2 to CO via RWGS-CL process. RWGS-CL is essentially a two-step process in which the perovskite oxide is first reduced under hydrogen to its oxygen deficient form (ABO3-Î´). In the second step, CO2 is converted over these oxygen vacant materials while the materials regain their stoichiometric forms. Since oxygen vacancy formation is the most crucial factor that drives this process, DFTâcalculated oxygen vacancy formation energy (Evac) presents an appropriate descriptor for the process. This Evac is largely dependent on the material composition and perovskite oxides are capable of accommodating different elements in their crystal structure. Hence, perovskite oxides present the perfect platform for tuning the oxygen vacancy formation characteristics of a material. We hence, undertook a screening process to predict different perovskite oxide with CO2 conversion capabilities. Based on our DFT calculation we predicted several earth abundant materials which can prove worthy of our purpose. CO2 conversion capability of these predicted materials was tested via temperature programmed experiments. Lanthanum and calcium based materials revealed unprecedented CO formation yields and rates. Detailed investigation of the effect of composition tuning of lanthanum and calcium based materials has been done to optimize the CO2 conversion performance of these materials.