Effect of Mo addition on the microstructure and catalytic performance Fe-Mo catalyst

Abstract

Fe-Mo catalyst with different molar ratios (1:0, 1:0.5, 1:1, 1:2, 1:3) were prepared by chemical co-precipitation method, and they were added to phenolic resin as catalysts. The microstructure and physicochemical properties of catalyst and crystalline carbon after phenolic resin pyrolysis were characterized by XRD, SEM, FT-IR, XPS and TEM. The results showed that the Fe/Mo molar ratio played a significant role in the graphitization of phenolic resin and the morphology of carbon nanotubes. The graphitization of the phenolic resin first increased and then decreased with the addition of Mo. When the Fe/Mo molar ratio was 1:2, the phenolic resin achieved the highest graphitization, and the formed carbon nanotubes had the highest crystallinity. The Fe atoms were in an electron-deficient state due to the electrons transferring from Fe to Mo, which enhanced the hydrocarbon compounds absorption on the surface of catalyst. And Mo was carbonized by carbon atoms to form α-MoC1-x, and then decomposed into β-Mo2C and graphite carbon, obtaining carbon atoms orderly arrangement and carbon nanotubes. Therefore, both the grain size and electron structure of catalyst significantly affect the catalytic properties of Fe-based catalyst.