R. Guil-Lo´pez et al. / Journal of Solid State Chemistry 190 (2012) 285–295
295
XRD result of the E-3 sample (Fig. 1f) shows the absence of
Acknowledgment
corresponding Mo-peaks, which could be explained (i) by the
formation of an amorphous Mo-phase; or (ii) by a Mo-crystalline
particle with size below 2 nm (the XRD crystal size limit,
2 nm, was estimated from the references [37,38]). However, the
absence of amorphous or crystalline MoC particles in the TEM-
micrograph (Fig. 9a) may be indicating either the Mo-particle
size in E-3 sample is really small, below 1–2 nm (because
EDX-microanalysis proves the Mo presence case), or the Mo metal
diffusion into the carbon support to form the MoC phase into the
carbon structure.
In summary, the use of the three techniques (XRD, EDX
and TEM) probes that (i) there is Mo on the carbon surface
of E-3 (by TEM EDX-microanalysis); and (ii) the really small
particle size of MoC in E-3, i.e., absence of crystalline particles
with size upper 2 nm by XRD and TEM, including the possibility of
the MoC formation through the Mo metal diffusion into CBv
support.
Financial support of the Project ENE2007-67533-C02/ALT is
gratefully acknowledged. RGL acknowledges the Consejo Superior
de Investigaciones Cientificas (CSIC) and the Project S2009ENE-
1743, for her contract.
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