118
M. I. Qadir et al.
Table 4.2 Naked mono- and bimetallic NPs prepared by magnetron sputtering into different types
of IL
Entry
IL
NPs
Size (nm)
References
1
EMIm.BF 4
Au
5.5 ± 0.86
[59]
2
BMIm.PF 6
Au
2.6 ± 0.3
[66]
3
(BCN)MIm.NTf 2
Au
4–8
[67]
4
(BCN)MIm.NTf 2
Au
5–7.2
[67]
5
(HSE)MIm.NTf 2
Au
8–22.9
[67]
6
(MeOE)MIm.NTf 2
Au
4–6.8
[67]
7
(BCN)MIm.NTf 2
Ag
5–14
[68]
8
(HSE)MIm.NTf 2
Ag
8.7–12
[68]
9
(MeOE)MIm.NTf 2
Ag
8.2–15.5
[68]
10
BMIm.PF 6
Ag
2–3
[68]
11
(BCN)MIm.NTf 2
Pd
1.4–2.9
[69]
12
BMIm.PF 6
Pd
2–4.5
[70]
13
Me 3 PrN.NTf 2
Pt
2–3
[71]
14
BMIm.PF 6
Au/Ag
2.6 ± 0.33
[60]
15
TMPA.TFSA
Au/Pt
1.5 ± 0.4
[72]
16
EMIm.BF 4
Au/Cu
2.6–3.4
[73]
17
HyEMIm.BF 4
Pd/Au
4.4–8.6
[74]
(TMPA.TFSA) = 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate (HyEMI-BF 4 )
side chain towards the vacuum/IL interface [62]. It is very probable that in
(BCN)MIm.NTf 2 IL, the surface is enriched with –CN groups (pointed towards
the vacuum/IL interface), which drive the anisotropic nucleation and growth of the
NPs [62], as opposed to the less anisotropic [(MeOE)MIm.NTf 2 ] IL, in which the
functional groups are located preferentially away from the liquid surface. Moreover,
they also observed by High-Sensitivity Low-Energy Ion Scattering (HS-LEIS)
analysis that the sputtered NPs tend to migrate deeper into the regions of the ILs
containing lower coordinating groups (–OMe), whereas the small nanoparticles are
present close to the fluid surface, having a single monolayer of IL surrounded by
ILs associated with strong sigma-donating groups (–CN and –SH). A similar study
was also carried out for Pd NPs [63].
It is well known that the discharge time does not affect the shape and size distribution of the NPs in ILs. Only the concentration of NPs increases with the increase in
sputtering time. On the other hand, the discharge current can affect the size distribution. The size of Au, Ag and Pd NPs increases with an increase in discharge current
[60, 64]. This tendency may be correlated with an increase in the deposition rate of
sputtered atoms. When higher deposition rates are used, more metal atoms/clusters
hit the surface of the IL per unit of time, changing the kinetics of particle growth on
the surface of the IL. As the molecular arrangement of the surface of the IL gradually
changes towards the bulk conformation, the environment in which the NPs grow will
M. I. Qadir et al.
Table 4.2 Naked mono- and bimetallic NPs prepared by magnetron sputtering into different types
of IL
Entry
IL
NPs
Size (nm)
References
1
EMIm.BF 4
Au
5.5 ± 0.86
[59]
2
BMIm.PF 6
Au
2.6 ± 0.3
[66]
3
(BCN)MIm.NTf 2
Au
4–8
[67]
4
(BCN)MIm.NTf 2
Au
5–7.2
[67]
5
(HSE)MIm.NTf 2
Au
8–22.9
[67]
6
(MeOE)MIm.NTf 2
Au
4–6.8
[67]
7
(BCN)MIm.NTf 2
Ag
5–14
[68]
8
(HSE)MIm.NTf 2
Ag
8.7–12
[68]
9
(MeOE)MIm.NTf 2
Ag
8.2–15.5
[68]
10
BMIm.PF 6
Ag
2–3
[68]
11
(BCN)MIm.NTf 2
Pd
1.4–2.9
[69]
12
BMIm.PF 6
Pd
2–4.5
[70]
13
Me 3 PrN.NTf 2
Pt
2–3
[71]
14
BMIm.PF 6
Au/Ag
2.6 ± 0.33
[60]
15
TMPA.TFSA
Au/Pt
1.5 ± 0.4
[72]
16
EMIm.BF 4
Au/Cu
2.6–3.4
[73]
17
HyEMIm.BF 4
Pd/Au
4.4–8.6
[74]
(TMPA.TFSA) = 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate (HyEMI-BF 4 )
side chain towards the vacuum/IL interface [62]. It is very probable that in
(BCN)MIm.NTf 2 IL, the surface is enriched with –CN groups (pointed towards
the vacuum/IL interface), which drive the anisotropic nucleation and growth of the
NPs [62], as opposed to the less anisotropic [(MeOE)MIm.NTf 2 ] IL, in which the
functional groups are located preferentially away from the liquid surface. Moreover,
they also observed by High-Sensitivity Low-Energy Ion Scattering (HS-LEIS)
analysis that the sputtered NPs tend to migrate deeper into the regions of the ILs
containing lower coordinating groups (–OMe), whereas the small nanoparticles are
present close to the fluid surface, having a single monolayer of IL surrounded by
ILs associated with strong sigma-donating groups (–CN and –SH). A similar study
was also carried out for Pd NPs [63].
It is well known that the discharge time does not affect the shape and size distribution of the NPs in ILs. Only the concentration of NPs increases with the increase in
sputtering time. On the other hand, the discharge current can affect the size distribution. The size of Au, Ag and Pd NPs increases with an increase in discharge current
[60, 64]. This tendency may be correlated with an increase in the deposition rate of
sputtered atoms. When higher deposition rates are used, more metal atoms/clusters
hit the surface of the IL per unit of time, changing the kinetics of particle growth on
the surface of the IL. As the molecular arrangement of the surface of the IL gradually
changes towards the bulk conformation, the environment in which the NPs grow will