Enhanced activity of La1-xMnCuxO3 perovskite oxides for chemical looping steam methane reforming

Chemical looping steam methane reforming (CL-SMR) is a promising pathway for producing syngas and hydrogen. A series of La 1-x MnCu x O 3 (x = 0, 0.05, 0.1, 0.15, 0.2) perovskites as the oxygen carriers were prepared via sol-gel method. The physicochemical properties of oxygen carriers were determined by XRD, BET, H 2 -TPR and CH 4 -TPR. Compared with the pure LaMnO 3 , La 1-x MnCu x O 3 oxygen carriers exhibited smaller crystal size and cell volume, and better reducibility . La 1-x MnCu x O 3 oxygen carriers also exhibited good oxygen mobility and high reactivity during the CL-SMR process. In the methane partial oxidation stage, the syngas productivity of La 1-x MnCu x O 3 (2.79–5.20 mmol/g) increased gradually with the Cu content. La 0.85 MnCu 0.15 O 3 and La 0.8 MnCu 0.2 O 3 showed higher CO selectivity and appropriate H 2 /CO ratio (1.92–2.10). In the water splitting stage, the H 2 contents over La 0.85 MnCu 0.15 O 3 and La 0.8 MnCu 0.2 O 3 began to decrease after the second cycles. However, the H 2 contents maintained at a relatively stable level during 3–11 cycles, suggesting a thermal stability. There was no CO formed in the water splitting step during 3–11 cycles, indicating better carbon formation resistance.