Porous Co-Pt Nanoalloys for Production of Carbon Nanofibers and Composites

The controllable synthesis of carbon nanofibers (CNF) and composites based on CNF (Metals/CNF) is of particular interest. In the present work, the samples of CNF were produced via ethylene decomposition over Co-Pt (0-100 at.% Pt) microdispersed alloys prepared by a reductive thermolysis of multicomponent precursors. XRD analysis showed that the crystal structure of alloys in the composition range of 5-35 at.% Pt corresponds to a fcc lattice based on cobalt (Fm-3m), while the CoPt (50 at.% Pt) and CoPt3 (75 at.% Pt) samples are intermetallics with the structure P4/mmm and Pm-3m, respectively. The microstructure of the alloys is represented by agglomerates of polycrystalline particles (50-150 nm) interconnected by the filaments. The impact of Pt content in the Co1-xPtx samples on their activity in CNF production was revealed. The interaction of alloys with ethylene is accompanied by the generation of active particles on which the growth of nanofibers occurs. Plane Co showed low productivity (similar to 5.5 g/g(cat)), while Pt itself exhibited no activity at all. The addition of 15-25 at.% Pt to cobalt catalyst leads to an increase in activity by 3-5 times. The maximum yield of CNF reached 40 g/g(cat) for Co0.75Pt0.25 sample. The local composition of the active alloyed particles and the structural features of CNF were explored.

Automated summary

In this study, Co-Pt alloy catalysts were prepared by reductive thermolysis, and carbon nanofibers (CNF) were successfully synthesized. It was found that the addition of an appropriate amount of platinum to the alloy can enhance the activity of the catalyst, with a maximum yield of 40 g/g(cat). The structure of CNF and the local composition of active particles were also investigated.