Page 80 - Synthesis of Functional Nanoparticles Using an Atmospheric Pressure Microplasma Process - LiangLiang Lin

Chapter 4
as well as excited molecular states, produced in non-equilibrium microplasma can further contribute to the suppression of TiOx formation.
TiN
TiO2 (Anatase) TiO2 (Rutile)
10 ml/min H2
5 ml/min H2
3 ml/min H2
1 ml/min H2
0 ml/min H2
(200)
(111)
(220)
Intensity (a.u.)
30 40 50 60 70 80
2q (°)
Figure 4.6 XRD patterns of nanoparticles prepared at different H2 concentrations
Figure 4.7(a) presents the full range XPS spectrum of TiN nanoparticles synthesized at the condition 1. It is clearly shown that the sample surface mainly consists of titanium, nitrogen, carbon and oxygen, which agrees with our EDX result. The Ti 2p spectrum of TiN nanoparticles is also given in Figure 4.7(b). The deconvolution of the Ti 2p peak shows two components: the main peaks corresponds to TiO2 (Ti 2p3/2: 458.4 eV, Ti 2p1/2: 464.4 eV), and the two peaks with lower intensity are attributed to TiN (Ti 2p3/2: 454.9 eV, Ti 2p1/2: 460.6 eV).33,34 XPS measurement is very sensitive to the sample surface condition. Since TiOx are preferential to be formed in the absence of hydrogen, and nanoparticles are easily oxidized at the surface.35 Therefore, through Ti 2P peak deconvolution the TiO2 content is larger than TiN, which is the same to a previous research.33 Figure 4.7(c) shows the N 1s bands of the synthesized TiN nanoparticles. The major N 1s peak at 396.2 eV can be indexed to the typical nitrogen shifts of TiN component, while the other two minor peaks at 398.8 eV and 400.9 eV are attributed to N-organic compounds or impurities that adsorbed to the TiN surface.33,36
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(311) (222)