Chemical looping conversion of methane via Fe2O3-LaFeO3 calcined from LaFe-MOF precursor

Abstract

The effective utilization of natural gas resources is a promising option for the implementation of the “dual carbon” strategy. However, the capture of carbon dioxide with relatively lower concentration after the combustion of natural gas is the crucial step. Fortunately, the lattice oxygen is used for chemical cycle conversion of methane to overcome the shortcomings mentioned above. A method was proposed to synthesize perovskite for methane cycle conversion using metal organic framework as a precursor. Morphology and pore structure of Fe2O3-LaFeO3 composite oxides were regulated by precursor synthesis conditions and calcination process. Moreover, the chemical looping conversion performance of methane was evaluated. The results showed that the pure phase precursor of La[Fe(CN)6]·5H2O was synthesized with the specific surface area of 23.91 m2·g−1 under the crystallization of 10 h and the pH value of 10.5. Fe2O3-LaFeO3 was obtained by controlled calcination of La[Fe(CN)6]·5H2O and Fe2O3 with variable mass ratio. The selectivity of CO2 can reach more than 99% under the optimal parameters of methane chemical looping conversion: m(Fe2O3):m(LaFeO3) = 2:1, the reaction temperature is 900 °C, the lattice oxygen conversion is less than 40%. Fe2O3-LaFeO3 still has good phase and structure stability after five redox reaction and regeneration cycles.