7 纳米结构钛酸盐——能源转换和储存的新材料

3.6 m
[ 10 1]
(101) (101)
(004)
[001]
{001}
dissolving
recrystallizing
{101}
growing
titanate nanowires
anatase nucleus
truncated octahedral bipyramid seeds
bipyramid
TiO2 nanotubes
Na2Ti3O7 + H2O TiO2 (nanotubes)
SEM images of raw material Na2Ti3O7 (a) together with product containing lots of nanotubes (b) low magnification and (c) high magnification. (Wei et al., Solid State Commu., 2005, 133, 493)
TiO2 (titanate) nanotubes/nanowires/nanosheets
TiO2 + NaOH (10M) Na2Ti3O7 H2Ti3O7 TiO2 (anatase) (Kasuga’s method, Langmuir, 1998, 14, 3160 )
TiO2 + NaOH (10M) Na2Ti3O7
前驱体H2Ti3O7纳米管的合成与表征
111

121
rutile
f
calcined at 600 C
e
10.9
9.6
Pure brookite phase
d
c
8.8
b a
7.6 6.0
60
20
30
40
2 theta / deg.
50
XRD patterns of products at 200 C for 24 h under different pH values.
ing l l o r
exfoliating
nanotubes
sp
Layered structure
sheets
itt ing
Nanowires/nanobelts
Scheme A possible mechanism for the formation of 1D nanostructural
nanotubes/nanowires/nanobelts.
NaOH conc. > 15 M, small size nanomaterials TiO Ti2O3 TiN TiB2 TiAl
+ NaOH → Na2Ti3O7 → H2Ti2O7
Brookite TiO2 nanotubes
Large TiO2 bipyramids
Titanate nanomaterials (前驱体)
2. Anatase TiO2 Bipyramids
(a)
(200) (310)
(b)
(110)
(312) (602) (113)
(112)
(204) (020)
(422)
5
15
25
35
2 theta / deg.
45
55
65
500 nm
(c)
[010]
(d)
[1 0 0
500 nm
]
XRD pattern (a) SEM image (b), and TEM images (c, d) of precursor synthesized at 200 C for 72 h.
pH=5.6
(a)
pH=7.0
(b)
1 m
100 nm
pH=7.9
(c)
pH=9.4
(d)
100 nm
100 nm
pH=10.5
(e)
pH=11
(f)
SEM images of products synthesized at 200 C for 48 h under different pH values.
500 nm
2 m
100 nm
1 m
光折射率 anatase 2.52 diamond 2.42
(a)
0.352 nm
(b)
0.48 nm
0n 60
m
500 nm
TEM images of product synthesized at 200 C for 48 h under a pH value of 10.5.
前驱体H2Ti3O7纳米线的合成与表征
titanate

(f)
11
(e)
10.5
(d)
Pure anatase phase
9.4
(c)
7.9
(b)
7.0
(a)
5.6
5 15 25 35
2 theta / deg.
45
55
65
XRD patterns of the products synthesized at 200 C for 48 h under different pH values.
K2Ti8O17 Na2Ti3O7 Zig arrangement
Na2CO3 + TiO2
1000 ℃
Dye-sensitized solar cells
H+
Na2Ti3O7
100 ℃
H2Ti3O7
Biosensors Lithium-ion Batteries Zn2Ti3O8 Li2ZnTi3O8 Li2CoTi3O8 Li2MgTi3O8 Li2CuTi3O8
(a)
(b)
0.256 nm 2 nm
(c)
111
0.481 nm 0.601 nm
(d) (d)
220
111
-
2 nm
Figure 3. TEM images of Zn2Ti3O8 nanowires obtained at the calcined temperatures of a) and b) 500, c) and d) 650 ℃, respectively.
titanate
Na+ or H+
releasing Na+ or H+
O2+
brookite
Scheme 1 A possible model for the transformation of titanate nanotubes to brookite TiO2 nanotubes. (Wei et al., Chem Comuun., 2008, 3657)
在水热条件下纳米线溶解成锐钛矿晶核 据报道，锐钛矿成核为切去尖头的八面体结构 {001}晶面的表面能是{101}晶面的表面能的1.4倍
A possible model for the formation of large anatase TiO2 bipyramid. (Wei et al., J Cry Growth, 2010, 312, 213)
nanotubes
TiO2-B nanowires
(a)
(b)
(a)
0.31 nm
(b)
Ti
200 100
O
-101
Na
Ti
Cu
Cu
20 µm
1 µm
200 nm
Energy / KeV
(c)
(d)
(c)
0.62 nm
200 400
(d)
Ti
0.33 nm
O Ti Cu Cu
20 µm
2 µm
20 nm
02 2
XRD patterns of (a) raw material Na2Ti3O7 and (b) product containing lots of nanotubes. (▽ TiO2)
TiO2 nanowires
Na2Ti3O7 + H2O TiO2 (nanowires)
SEM and TEM images of raw material Na2Ti3O7 (a) together with product containing lots of nanowires (Wei et al., Chem. Phys. Lett., 2004, 400, 231)
Nanotubes/nanowires
NaOH + TiO2 nanotubes nanowires anatase TiO2 brookite TiO2 rutile TiO2 TiO2-B
层状结构的钛酸盐 （合成/前驱体）
Dye-sensitized solar cells Lithium-ion Batteries
(a)
(b)
(c)
(d)
Highly crystalline
50 nm
SEM (a, b) and TEM (c, d) images of the brookite nanotubes synthesized at 200 C for 24 h under pH = 10.9.
首次合成纯相板钛矿纳米管
(a)
(b)
28 0.
nm 1. 0 nm
cross section
100 nm
(a)
no na be tu
111
(b)
▽
▽
▽
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