Transcript nanostructured mesoporous materials

Inorganic Nanostructured
Materials
Gerasimos Armatas
Research activities
Research activities focused on design and synthesis of
nanostructured mesoporous materials and their
applications, including:
• Nanoporous metal oxides using ‘soft’ or ‘hard’ templated
(nanocasting) self-assembly approaches
• Periodically ordered mesoporous polyoxometalatecontaining frameworks
• Nanostructured inorganic semiconductors
• Structural and chemical modification of
nanocomposite structures
• Applications in heterogeneous catalysis,
absorption, optoelectronics and gas
separation
50
40
c
103 m2/g
30
Pore volume (cm /g-nm)
20
3
3
Nitrogen adsorbed (cm /g STP)
Hexagonal Mesoporous Zirconia-POM
Nanocomposites
10
0
0.0
0.2
0.020
Dp=5 nm
0.016
0.012
0.008
0.004
0.000
0
0.4
5 10 15 20 25 30 35 40
Pore width (nm)
0.6
0.8
1.0
Relative pressure (P/Po)
Epoxidation of alkenes with H2O2 catalyzed by 37wt% PMo12/ZrO2
Conversion
(%)
TOF
(h-1)
Selectivity
epoxide:alcohol:ketone
cyclooctene
82
41.0
100:0:0
cyclohexene
30
7.5
47:43:10
methylcyclohexene
26
6.5
81:8:11
Styrene
30
7.5
5:0:95
methylstyrene
28
7.0
39:61:0
Substrate
Other catalytic systems include mesoporous
ZrO2/[SiW12O40]4-, ZrO2/[PW12O40]3-,
Al2O3/[PW12O40]3-, TiO2/[W10O32]4nanocomposites.
G.S Armatas et el., J. Mater. Chem. 2010, 20, 8631;
G.S.Armatas et el., J. Mater. Chem. 2011, 21, 2997
Mesoporous Cr2O3-Phosphomolybdic acid Solid
Solution Frameworks
Cr 2p
592 584 576 568
Binding energy (eV)
Cr 2p
Mo 3d
240 236 232 228 224
Binding energy (eV)
Mo 3p
Mo 3d
Cr 3p
P 2p
1000
b
O 1s
Photoelectron intensity (a.u.)
Photoelectron intensity (a.u.)
Photoelectron intensity (a.u.)
c. XPS
800
600
400
200
0
Binding energy (eV)
400oC
HF
Catalytic oxidation of 1-phenylethanol*
SBA-15
Cr(NO3)3
H3PMo12O40
SBA-15
Cr2O3/HPMo
Cr2O3/HPMo
Other materials are mesoporous Co3O4/[PW12O40]3-,
CeO2/MoO3, CeO2/Bi2O3.
Armatas et el., Chem. Mater. 2010, 22, 5739.
63wt% HPMo/Cr2O3
H2O2, 50 oC
*Conv. 87%, TOF=103 h-1, 5 min, CH3CN
Mesoporous Germanium Semiconducting Frameworks
(collaboration with Northwestern University, USA)
Band gap Evolution with Wall Thickness in a Nanostructured Semiconductor
Decreasing pore wall thickness, increasing energy band-gap
WT~2 nm
WT~1.5 nm
WT~1.3 nm
CB
Eg=1.86 eV
Eg=1.92 eV
Eg=1.97 eV
VB
bulk
nano
G.S. Armatas, M.G. Kanatzidis, Nano Lett. 2010, 10, 3330
Collaborators
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Prof. M. Kanatzidis (NU)
Prof. M. Louloudi (UoI)
Prof. P. Pomonis (UoI)
Prof. K. Triantafyllidis (AUTH)
Prof. I. Lykakis (AUTH)
Prof. M. Stratakis (UoC)
Dr. P. Chupas (ANL)
Funding