Influence of the molybdenum content in cobalt and molybdenum catalysts supported on magnesium oxide for the production of carbon nanotubes

ABSTRACT

The development of carbon nanotubes production has been subject of research seeking higher carbon yields and selective processes towards materials with superior purity and quality. Among the methods for nanotube synthesis, the catalytic route is a viable option for large-scale production, since it allows a more effective control of reaction. CoMo/MgO catalysts with low loading of cobalt, 5 wt.%, and three different loading of molybdenum, 5, 10 and 20 wt.%, were prepared by incipient wetness impregnation for high yield and pure carbon nanotubes. A detailed characterization of the catalysts and nanotubes indicated a relationship between their properties. Catalysts prepared with higher molybdenum loading showed higher formation of MgMoO₄ and CoMoO₄ indicating an enhanced interaction of MgO and cobalt with molybdenum. Excess of molybdenum in the catalyst caused a decrease in carbon yield and produced nanotubes with a lower degree of graphitization.

Keywords
carbon nanotube; cobalt; molybdenum; chemical vapor deposition