Supporting information for
Direct synthesis of alumina nanowires on ceramic substrates
using tin catalysts
Namjo Jeong,1,2*, Sung-kuk Hong3, Chansoo Kim1 and Kahee Kim4
1
Jeju Global Research Center, Korea Institute of Energy Research, 200, Haemajihaean-ro,
Gujwa-eup, Jeju Special Self-Governing Province, 695-971, Republic of Korea
E-mail: njjeong@kier.re.kr
2
Energy Materials and Convergence Research Department, Korea Institute of Energy Research,
71-2 Jang-dong, Yuseong-gu, Daejeon 305-343, Republic of Korea
E-mail: njjeong@kier.re.kr
3
Advanced Combustion Laboratory, Korea Institute of Energy Research, 71-2, Jang-dong,
Yuseong-gu, Daejeon, 305-343, Republic of Korea
E-mail: sungkookhong@kier.re.kr
4
Measurement and Analysis Team, Korea Advanced Nanofab Center, 960-10, Iui-dong,
Yeongtong-gu, Suwon 443-270, Republic of Korea.
E-mail: kahee.kim@kanc.re.kr
Fig. S1. Low- and high-magnification SEM images of (a) Bar-like Al2O3 nanowire assemblies
and (b) spindle-like Al2O3 nanowire assemblies.
Fig. S2. EDX spectra measured at (a) top and (b) lower parts of a Sn particle, and (c) a nanowire.
Fig. S3. XRD graph of raw substrate, SnO2/substrate, and Sn/Al2O3 nanowires/substrate. The
raw substrate is Al2O3 disc with a little aluminosilicate.
Fig. S4. HRTEM image showing the deposition of Sn nanoparticles on the surface of Al2O3
nanowires. White arrows indicate the deposited Sn nanoparticles.
Fig. S5. TEM and HRTEM images of Al2O3 nanochains synthesized without SnO2 nanoparticles.
An inset is the corresponding FFT image showing that the nanochains have -phased Al2O3
structure, a cubic structure with {440}, {400}, {311}, and {220} reflections (PDF#97-006-6559).
Fig. S6. A schematic image describing that (a) branching growth and (b) amalgamating growth
mechanisms of Al2O3 nanowires is controlled by an intelligent behavior of Sn catalyst.
Fig.
S7.
XPS
survey
spectra
of
raw
substrate,
SnO2/substrate,
and
nanowires/substrate. The raw substrate is Al2O3 disc with a little aluminosilicate.
Sn/α-Al2O3
Fig. S8. SEM images showing the effect of synthesis time on the growth of Al2O3 nanowire
assemblies: (a) 1, (b) 5, and (c) 60 min. Yellow arrows indicate the Al2O3 nanowires grown
from surface of Sn particles.
Fig. S9. (a) Low- and (b) high-magnification SEM images of products synthesized using only Al
powder as a starting source material.
Fig. S10. The Gibbs free energies of formation for SnO2, SiO2, and Al2O3.
Fig. S11. SEM images of Al2O3 nanowires synthesized on the surfaces of Al2O3 (a-c) monolith
and (d-f) foam.