In this review, recent patents on CO2-absorbent ceramics for high-temperature use and the mechanism of CO2 absorption by these absorbents are introduced. CO2 reduction technology is a large research field at the global level and the number of studies in this field is constantly increasing. The development of CO2 absorbents is included in the technology of CO2 reduction. Lithium complex oxides such as lithium zirconate and lithium silicate, calcium complex oxides, and alkaline earth complex oxides are all candidates for CO2 absorbents at high temperatures in the range of 700° to 1100 °C. These absorbent ceramics are useful for steam reformation of hydrocarbons-such as coal, oil, and natural gasto improve power generation efficiency.