  A way to produce new metal-carbon nanoobjects by transformation of a graphene
flake with an attached transition metal cluster under electron irradiation is
proposed. The transformation process is investigated by molecular dynamics
simulations by the example of a graphene flake with a nickel cluster. The
parameters of the nickel-carbon potential (I. V. Lebedeva et al. J. Phys. Chem.
C, 2012, 116, 6572) are modified to improve description of the balance between
the fullerene elastic energy and graphene edge energies in this process. The
metal-carbon nanoobjects formed are found to range from heterofullerenes with a
metal patch to particles consisting of closed fullerene and metal clusters
linked by chemical bonds. The atomic-scale transformation mechanism is revealed
by the local structure analysis. The average time of formation of nanoobjects
and their lifetime under electron irradiation are estimated for experimental
conditions of high-resolution transmission electron microscope (HRTEM). The
sequence of images of nanostructure evolution with time during its observation
by HRTEM is also modelled. Furthermore, the possibility of batch production of
studied metal-carbon nanoobjects and solids based on these nanoobjects is
discussed.
