Supporting Information
Nanocellulose-Assisted Formation of Porous
Hematite Nanostructures
Alesja Ivanova†, Ksenia Fominykh†, Dina Fattakhova-Rohlfing, Patrick Zeller, Markus
Döblinger and Thomas Bein*
Department of Chemistry and Center for NanoScience (CeNS), University of Munich
(LMU), Butenandtstrasse 5-13 (E), 81377 Munich, Germany
*Corresponding author: E-mail: [email protected]
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Figure S1. XRD pattern of an NCC free-standing film. The assigned signals correspond to
native cellulose (ICDD pattern 00-003-0289).
Figure S2. Photograph of free-standing nanocellulose-precursor composites prepared with
(a) FeCl3·6H2O, (b) FeCl2·4H2O, and Fe(NO3)3·9H2O (c) dried at 35 ºC. (d, e) NCC/iron
oxide precursor thin films coated on FTO glass from precursor solutions based on
FeCl3·6H2O (d), and Fe(NO3)3·9H2O (e) and calcined at different temperatures.
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Figure S3. SEM top view images revealing the effect of the iron precursor and calcination
temperature on the morphology of NCC-templated -Fe2O3 thin films. The films were
prepared from precursor solutions containing FeCl2·4H2O (top row: a1, b1, c1, d1) or
Fe(NO3)3·9H2O (bottom row: a2, b2, c2, d2) and calcined at 300 ºC (a1, a2), 400 ºC (b1, b2),
500 ºC (c1, c2), and 600 ºC (d1, d2). The scale bars correspond to 100 nm.
Figure S4. TEM images a1, b1 (scale bars correspond to 10 nm), a3, b3 and SAED patterns
a2, b2 (scale bars correspond to 2.5 1/nm) of NCC-templated iron oxide thin films prepared
from precursor solutions containing FeCl3·6H2O and calcined at 500 ºC (a1, a2, a3) and 600
ºC (b1, b2, b3).
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Figure S5. XRD patterns revealing the temperature-dependent development of phase
composition of NCC/Fe(NO3)3·9H2O composites calcined at different temperatures (a) after
drying at 35 °C (assigned as RT) and after DHT treatment (b). The assigned signals
correspond to native cellulose (ICDD pattern 00-003-0289) (□) and hematite (ICDD pattern
00-033-0664) (*).
Figure S6. X-ray photoelectron spectra of iron chloride/NCC composite films coated from
FeCl3·6H2O (a1, a2, a3) and FeCl2·4H2O (b1, b2) precursors and dried at different
conditions: at room temperature (RT), at 100 °C at high humidity (100 °C DHT) and at 100
°C and 300 °C in ambient humidity conditions. The spectra reveal the development of Fe 2p
(a1, b1), C 1s (a2, b2) and O 1s (a3) peaks. The points in figure a3 show the recorded oxygen
spectra fitted with a Doniach-Sunjic line shape convoluted with a Gaussian and linear
background subtraction. The three peaks with maxima at 530.1 eV, 531.3 eV and 532.5 eV
correspond to oxygen in iron oxide, iron hydroxide and water/cellulose, respectively. Spectra
were taken using a Mg Kα source.
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Figure S7. Top view SEM images of NCC-templated -Fe2O3 thin films calcined at 300 ºC
(a1, a2), 400 ºC (b1, b2), 500 ºC (c1, c2), and 600 ºC (d1,d2) after humidity treatment at 100
°C. The films were spin-coated on silicon wafers from aqueous precursor solutions
containing NCC and FeCl3·6H2O (a1, b1, c1, d1) or Fe(NO3)3·9H2O (a2, b2, c2, d2). The
scale bars correspond to 100 nm.
Figure S8. Nitrogen sorption isotherms measured on NCC-templated -Fe2O3 powders after
calcination at 500 °C. The samples were prepared from precursors containing NCC and
FeCl3·6H2O (a), FeCl2·4H2O (b) and Fe(NO3)3·9H2O (c) without delayed humidity treatment.
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