一步法合成Mo2C/AC催化剂及其CO2加氢转化CO性能研究OA

Using molybdenum-doped coconut shells as raw materials,Mo2C/AC catalyst was successfully prepared without adding of external carbon sources or reducing gases by taking advantage of the reducing atmosphere generated during the biomass pyrolysis process.The catalyst was characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS)and transmission electron microscopy(TEM).The results showed that H2/CO produced during the pyrolysis of coconut shells could in situ induce the reduction and carburization of molybdenum oxides to form Mo2C.The high specific surface area of coconut shell activated carbon could evenly disperse the catalyst particles,and the pore effect could effectively anchor and limit the size of Mo2C particles,thereby preparing nano-scale Mo2C/AC catalysts.The Mo2C/AC-900 catalyst prepared at the optimal self-activation temperature of 900 ℃ had a Mo2C particle size of only 8.62 nm on the surface of activated carbon,and there were no obvious impurity peaks in the XRD characterization,indicating that the purity of Mo2C on the surface of activated carbon was high.Mo2C/AC-900 exhibited excellent CO2 hydrogenation conversion performance(24.57％of conversion rate and over 99％of selectivity)at 600 ℃,with a V(CO2)∶V(H2)ratio of 1∶2,a volume space velocity of 60 000 mL/(g·h)and under the condition of Mo loading of 5％,and its stability sustained for more than 140 h.