We will summarize our recent work on the development of materials, reactors and systems for clean energy including carbon capture, water splitting and CO2 reuse. Oxy-combustion is an efficient carbon capture technology that requires high efficiency air separation, we will show how using metal oxides/pervoskites in the form of ion-transport membrane enables the integration of air separation and fuel oxidation. Integrated with gasification, it can be applied to coal. Similar materials can be used but with different elements and catalysts for water splitting using intermediate temperature heat, CO2 reduction as well as the conversion of natural gas to chemicals feedstock.