Chemical looping conversion of methane via Fe_(2)O_(3)-LaFeO_(3)calcined from LaFe-MOF precursor

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 Fe_(2)O_(3)-LaFeO_(3)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)]·5H_(2)O was synthesized with the specific surface area of 23.91 m^(2)·g^(-1)under the crystallization of 10 h and the pH value of10.5.Fe_(2)O_(3)-LaFeO_(3)was obtained by controlled calcination of La[Fe(CN)_(6)]·5H_(2)O and Fe_(2)O_(3)with variable mass ratio.The selectivity of CO_(2)can reach more than 99%under the optimal parameters of methane chemical looping conversion:m(Fe_(2)O_(3)):m(LaFeO_(3))=2:1,the reaction temperature is 900℃,the lattice oxygen conversion is less than 40%.Fe_(2)O_(3)-LaFeO_(3)still has good phase and structure stability after five redox reaction and regeneration cycles.

Cobalt doped Fe-Mn@CNTs catalysts with highly stability for lowtemperature selective catalytic reduction of NO_(x)

In this paper,we report the fabrication of cobalt-doped de-NO_(x)catalyst by pyrolyzing an analogous metal-organic framework-74(MOF-74)containing Fe&Mn.The resulted catalyst exhibits distinctive microstructures of manganese,cobalt,and iron immobilized on N-doped carbon nanotubes(CNTs).It is found through experiments that the trimetallic catalyst Fe_(2)Mn_(1)Co_(0.5)/CNTs-50 has the best NH_(3)-selective catalytic reduction(SCR)performance.The Fe_(2)Mn_(1)Co_(0.5)/CNTs-50 exhibited excellent water and sulfur resistance and good stability under the harsh gas environment of 250℃ and/or 170℃,NO=NH_(3)=1,000 ppm,8 vol.%O_(2),20 vol.%H2O,1,000 ppm SO_(2),and gas hourly space velocity(GHSV)=75,000 h^(-1).The de-NO_(x)conversion was maintained about 55%and 25%after 192 h.The water and sulfur resistance performance were much higher than commercial vanadium series catalyst.The highly water and sulfur resistance performance may be attributed to the unique core-shell microstructure and the synergistic effect of manganese,cobalt,and iron which helps reduce the formation for byproducts(NH_(4)HSO_(4)).This study may promote to explore the development of a high stability catalyst for low-temperature selective catalytic reduction of NO_(x)with NH_(3).