Copper and cobalt co-doped ferrites as effective agents for chemical looping CO2 splitting

The sintering of oxygen carrier materials can be circumvented by operating chemical looping at relatively low temperatures (<750 °C). However, low temperature has a degrading effect on the redox kinetics of the materials and thereby limited efficiencies. In the current work, we report several Co, Cu co-doped spinel-structured ferrites as effective redox materials in the chemical looping scheme for CO2 thermo splitting at 650 °C. Cu0.2Co0.8Fe2O4 presents high average CO2 splitting rate of ~144.9 μmol.g−1.min−1 and CO yield of ~9.0 mmol. g−1 with satisfactory stability over cyclic redox operations. The improved performance can be attributed to the improved reduction of iron oxides by Cu, Co co-dopant, and the reversible phase change of the reduced sample in the CO2 splitting stage. Additionally, increasing Cu doping amount leads to the formation of insufficiently active impurities which is unfavorable for the CO2 thermo-splitting. The synergy in this work can be helpful for the design of the redox materials at moderate temperatures.