COMMUNICATION
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Facile fabrication of a Prussian Blue film by direct aerosol deposition
on a Pt electrodew
a
a
a
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Zhenyu Chu, Yu Liu, Wanqin Jin,* Nanping Xu and Bernd Tieke
Received (in Cambridge, UK) 26th March 2009, Accepted 16th April 2009
First published as an Advance Article on the web 8th May 2009
DOI: 10.1039/b906022g
A facile aerosol deposition approach, which was simulated as
feasible by density functional theory (DFT), was applied to
synthesize a Prussian Blue (PB) film directly on a Pt electrode
surface.
and the electron clouds of Fe, C and N are superimposed.
It can be seen that the electron cloud of the Pt does not
overlap with that of the C atom. Comparing the PDOS of
C in PB crystals and PB adsorbed onto a Pt (110) surface
(
between the Pt and C atoms; a van der Waals force. The
ESI, Fig. S2w), we found that there was an interaction
Prussian Blue (PB) is an old but important metal hexa-
cyanoferrate. Since it was discovered in the early 1700s, many
researchers have been interested in its special properties due to
the different valences of the transitional metal Fe. Many
research groups have undertaken a huge amount of work in
the fields of magnetic properties, optical properties, electron
calculated bond population confirmed the length of the C–Pt
˚
bond to be 2.19842 A (ESI, Table S3w).
Based on the above simulation results, an aerosol deposition
was adopted to prepare a Pt electrode modified with a PB film.
0.01 M K
to two ultrasonic nebulizers, respectively. After pre-treatment
of the Pt electrode (ESI, S4w), K [Fe(CN) ] was adsorbed on
the surface of the Pt by using the aerosol of K [Fe(CN) ] in an
air-tight organic glass container at room temperature for 2 h.
Subsequently, the FeCl aerosol reacted with the K [Fe(CN) ]
6
4 6 3
[Fe(CN) ] and FeCl aqueous solutions were added
1
–5
transfer and biosensors. PB can reduce the overpotential of
reduction to avoid interference from other substances,
H
2
O
2
4
6
6
such as ascorbic acid, and PB-based biosensors have advantages
for selectivity and accuracy. During the last century, preparation
methods for PB-modified electrodes were discovered and
applied. Electrochemical deposition and self-assembly are
the traditional, and still current, approaches to fabricating
4
6
3
4
to form a PB film. Finally, the prepared electrode was washed
with de-ionized water and heated at 100 1C for 1 h to
dehydrate it.
7
–9
PB-modified electrodes.
However, these approaches have
their own limits, as electrochemical deposition may not be
easily used in large-scale production. In our previous work,
we studied the preparation of PB-modified electrodes by a
Cyclic voltammetry (CV) and atomic force microscopy
(AFM) characterizations were performed in order to gain
information on the growth of the PB film.z PB film samples
of different deposition times (2, 3, 4, 5, 6 and 7 h) were
prepared on the Pt surface. The effect of the deposition time
is shown in Fig. 2(a). The amount of PB was also calculated
(Fig. 2(b)). The amount of PB on the Pt surface increased with
the deposition time; it grew slowly at the beginning of the
deposition process because only small amounts of PB existed
as growth cores on the Pt electrode surface. The PB particles
then grew more quickly than before. However, the growth rate
slowed when the time reached 5 and 6 h; the surface of the
1
0
self-assembly approach. This method requires the adsorption
of a layer of polyelectrolyte to increase the electrostatic charge
4ꢀ
for attracting ferricyanide anions, [Fe(CN)
6
]
, the poly-
electrolyte layer possibly increasing the distance between
the PB outer layer and the electrode surface, resulting in a
decreased electron transfer rate. Consequently, we have
developed here a novel and facile method for directly depositing
PB on a Pt surface.
Firstly, we simulated the performance of PB adsorbed onto
a Pt surface by density functional theory (DFT) using the
Cambridge sequential total energy package (CASTEP). The
Perdew–Burke–Ernzerhof functional (PBE) of the gradient-
corrected functional was chosen as the exchange-correlation
functional. The partial density of the states (PDOS),
bond population and electron density difference were then
calculated (ESI, S1w). Fig. 1 is the terminative optimization
result of the Fe–C–N–Fe unit freely adsorbed onto the Pt(110)
surface. The electron density isosurface is coloured in green,
a
State Key Laboratory of Materials-Oriented Chemical Engineering,
College of Chemistry and Chemical engineering, Nanjing University
of Technology, 5 Xinmofan Road, Nanjing 210009, P. R. China.
E-mail: wqjin@njut.edu.cn; Fax: +86 25-8317-2266;
Tel: +86 25-8317-2266
Institut fu¨r Physikalische Chemie der Universita¨t zu Ko¨ln,
Luxemburger Straße 116, D-50939 Ko¨ln, Germany
b
w Electronic supplementary information (ESI) available: Experimental
and simulation details S1–S4, and AFM images S5. See DOI:
Fig. 1 The simulated electron density isosurface of optimized PB
10.1039/b906022g
freely adsorbed onto a Pt(110) surface.
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566 | Chem. Commun., 2009, 3566–3567
This journal is ꢁc The Royal Society of Chemistry 2009