1 research outputs found
Atomic-Scale Mechanism on Nucleation and Growth of Mo<sub>2</sub>C Nanoparticles Revealed by in Situ Transmission Electron Microscopy
With a similar electronic
structure as that of platinum, molybdenum carbide (Mo<sub>2</sub>C)
holds significant potential as a high performance catalyst across
many chemical reactions. Empirically, the precise control of particle
size, shape, and surface nature during synthesis largely determines
the catalytic performance of nanoparticles, giving rise to the need
of clarifying the underlying growth characteristics in the nucleation
and growth of Mo<sub>2</sub>C. However, the high-temperature annealing
involved during the growth of carbides makes it difficult to directly
observe and understand the nucleation and growth processes. Here,
we report on the use of advanced in situ transmission electron microscopy
with atomic resolution to reveal a three-stage mechanism during the
growth of Mo<sub>2</sub>C nanoparticles over a wide temperature range:
initial nucleation via a mechanism consistent with spinodal decomposition,
subsequent particle coalescence and monomer attachment, and final
surface faceting to well-defined particles with minimum surface energy.
These microscopic observations made under a heating atmosphere offer
new perspectives toward the design of carbide-based catalysts, as
well as the tuning of their catalytic performances