Design of novel perovskite type oxygen carriers (ABB')O3 for chemical looping reforming and production of hydrogen with CO2 capture.

This project focuses on the research fields of hydrogen and natural gas that are presented in the call from RENERGI. The aim of the project is to increase our understanding of the redox properties of novel perovskite type oxides to be used in new technolo gies; such as hydrogen production combined with syngas production or CO2 capture depending on the process Our strategy is to approach the redox energetics of perovskite oxides using a combined experimental and computational approach. Our focus is to obta in redox energetics for perovskites where such data are not available, especially for reduction of cations from 3+ to 2+ on the B-site of the perovskite. A vast number of possible compounds/systems are potentially interesting. Systems of the Ln1-xAex(B1-y B'y)O3-d are in focus. Here Ln is a lanthanide cation, Ae an alkaline earth metal while B and B' typically are first row transition metals. Hence, transition metals in formal oxidation state II, III and IV are all relevant. In the present proposal ab-init o density functional theory determination of enthalpies of formation of ternary oxides from their binary constituents which subsequently determines the enthalpy of oxidation is central. From these calculations we will choose specific systems for careful e xperimental studies. Several experimental techniques will be used to characterize the thermochemistry of the selected perovskite oxides. Non-stoichiometry oxygen partial pressure isotherms will be measured by thermogravimetry (TG) and coulometric titrati on, and differential scanning calorimetry (DSC) will be used to determine average enthalpies of oxidation. Tools will also be developed to calculate/estimate good energetic data for a given composition, in order to tailor candidate materials for CLC and CLR processes. Such tools will be based on defect equilibriums/solid solution models and simple scaling of existing redox data.