The reverse water gas shift reaction, its proposed mechanisms, currently used and proposed catalysts and an intensified version of the reaction are evaluated for their abilities to significantly reduced CO2atmospheric concentration.

Carbon dioxide conversion to carbon monoxide was studied in an intensified chemical looping reverse water−gas shift reaction (RWGS−CL) process using parent perovskite-type oxides as oxygen carriers. Five different strontium-doped lanthanum cobaltites, La 1−X Sr X CoO 3−δ (0 ≤ X ≤1 in steps of 0.25), were synthesized using the Pechini method and their structures were examined with X-ray diffraction (XRD). Temperature-programmed (H 2 -TPR, CO 2 -TPO) and isothermal CO 2 conversion experiments were performed to evaluate their properties and abilities for carbon dioxide conversion. The production of carbon monoxide from the reduced parent oxides is enhanced when X = 0.25. From the three H 2 -reduction temperatures studied (400, 500, and 600 °C), 500 °C was determined as the optimum, presumably due to the formation of mixed oxides and metallic cobalt crystalline phases (observed via XRD) in close contact. Furthermore, isothermal CO 2 conversion rates increased with temperature over the tested range (650 to 850 °C). Results indicated that perovskite-type oxides can be used as oxygen carriers in a RWGS−CL process where separation of the products is achieved, which facilitates subsequent synthesis of liquid hydrocarbons or methanol. Hydrogen obtained by water splitting or electrolysis would make the process sustainable assuming solar or wind is used to drive the reaction.

Earth abundant perovskite oxides exhibiting the highest CO2 conversion rates by the RWGS-CL process at the low temperature of 500 °C.