Cover page

1
Cover page
The format of your lab report is suggested to use
for this experiment.
Experiment XX The Lanthanide-based
nanoparticles preparation and characterization N
ame Students and lab partner's name ID
number K 0000XX (Not your SSN number) Date
Month. day, 2007 Location N 264XX Texas A
M University - Kingsville Chemistry
department General chemistry (111X)
2
Introduction (Half or ¾ of one page)
Page 1
The kinetics of the ORR were investigated at
SG-LSCF, deposited by screen-printing on a
samarium doped ceria (SDC) electrolyte, using
electrochemical impedance spectroscopy and cyclic
voltammetry at temperatures ranging from 400 to
700 ?C. The results show that the LSCF cathode
is stable and exhibits a high exchange current
density (and low charge transfer resistance),
yielding an apparent activation energy for the
ORR of ca. 120 kJ/mol. It was also found that
the SG-LSCF on SDC cathode was approximately one
order of magnitude more active than standard
manganite-based composite cathodes, deposited on
yttria stabilized zirconia, studied under
otherwise identical operating conditions. Keywo
rds (three to five key words) cathode,
microstructure characterization, oxygen reduction
3
Objectives (two five objectives)
P 2

• To fabricate the nanostructured LSCF cathode
  using Sol-Gel method
• To determine the kinetics of the so-prepared LSCF
  using electrochemical impedance spectroscopy and
  cyclic voltammetry.
• To calculate the the apparent activation energy.
  

Theory (100-200 words use your own explanation
of the theory of the experiment, general ideas,
principles, concepts, etc. Ideas from the
Introduction section of the lab manual may be
used. Include main equations, chemical formulas,
etc)
Solid oxide fuel cell (SOFC) has been called one
of the green energy sources in the 21st century
because it has ultrahigh energy conversion
efficiency and ultralow emission of air
pollution. Currently, it has drawn much attention
in developing the cathode and electrolyte
material with long life-span and highly ionic
conductivity operating in intermediate
temperature range LSCF perovskite-type membrane
displayed 2 to 4 orders of magnitude higher
oxygen permeation fluxes than those of the LSM
cathode at the same operating temperature.
Traditionally, the SOFC has been fabricated by
heating the starting materials at high
temperature, which will decrease the TPB length,
consequently resulting in lower apparent exchange
current density. The Sol-Gel (SG) method is
becoming an increasingly popular route for the
preparation of metal oxides, involving SOFC, due
to its time and energy saving advantages 1.
Increasing attention on SG-formed oxides also
arises from their highly porous structure,
providing very high surface areas, useful for
many applications.
4
Procedure (200 words approximately general
description of the procedure as it was performed,
However, a flowchart is suggested to use)
P 3
The solution was refluxed and stirred
continuously for 4 hrs under a water bath and
then cooled to room temperature. The solution was
condensed with evaporation of ethanol for
approximately 4hrs to obtain sol-precursor which
is approximately 1/3 of starting volume. The
sol-precursor was pipetted onto the electrolyte
by aliquoting 80 ?L sol-precursor onto the solid
electrolyte disks and preheated for 15 min. The
second layer was deposited by aliquoting another
80 ?L sol-precursor and followed by heating 900
?C for 4 hours (shown in Fig. 1.)
La(NO3)3, Sr(NO3)2, Co(NO3)2, Fe(NO3)3
LSCF-containing solution
Refluxing for 4 hrs
homogeneous solution
Evaporation
LSCF-containing Sol
pipeting
Wet-film on Ni-SDC
Heat-treatment
LSCF-perovskite cathode
Fig. 1 Flowchart of preparation
characterization of LSCF cathode
5
P 4
Report sheet (From the lab manual, neatly written
in pen (pen preferred)/pencil, to be completed
before leaving the laboratory. Graphs may be
done neatly by hand or by computer)
Table 1 Preparation of LSCF cathode

Table 2 Component of Base solution
1) 1000 ml reactor (Three neck flask) 2) 500
ml Polyols 3) 3.2361 g Daxad 11G (100 wt
base on Ag) 4) 61.4859 g Mica with TiO2 5)
Pouring at reaction temp. 6) Total volumes 600
ml 7) Concentration 0.05 M LSCF 5,000 ppm
6
Results and discussion (200 words approximately
What are the main results of the experiment?
What conclusions can be derived from the results?
How good is the accuracy of your results? What
systematic and random errors affected your
results? Include some values and formulas when
describing results and accuracy. However empty
words are not expected)
P 5
Fig. 3 displayed X-ray powder diffraction (XRD)
patterns taken from SG-formed La0.8Sr0.2Co0.8Fe0.2
O3 (SG LSCF) powders and cathode on Sm-doped
Ceria, respectively, heated at 900?C for 4hrs in
air. The typical SG LSCF XRD schematics displayed
the alignment with the perovskite LSCF with
tetragonal phase (JCPSD no. of 48-0125), which is
consistent with the report by Riza and his
co-worker, whereas some pattern showed slightly
distorted from tetragonal to orthorhombic. The
XRD patterns provided the evidence of formation
of crystalline structure and miller indices were
labeled for identification of various peaks. It
is remarkable that the intensity of (101) peak at
2? of 31.5? is the strongest and there exists
peak splitting due the difference of lattice
constant of c and a, which will result in the
non-uniform microstress, lattice distortion.
The phase transition of LSCF from rhombohedral to
cubic was reported by Shaorong Wang who prepared
their samples from coprecipitation and heated at
1100 ?C. This phenomenon is essentially the same
as what we observed in XRD study. The deformation
of crystal may result from the dopant of Fe ion
with larger radius than that of Co ions. Another
reason could be attributed to the stronger bond
of Fe-O than Co-O.
7
Conclusion summarize what you achieved and
learned from the expt using four to six sentences
P 6
XRD results indicated that the LSCF was mainly
composed of tetragonal phase and with the lattice
distortion to orthomobic phase. TEM and XRD
quantitative analysis indicated that particle
size and crystalline size were 20-50 nm and 20-40
nm respectively, which will result in long length
of triple phase boundary. By using Sol-Gel
method, the uniform thickness of cathode can be
obtained. The high porosity of SG LSCF cathode is
to facilitate gas transport and to accelerate
electronic kinetics. The kinetics of ORR on
SG-formed LSCF cathode was determined faster than
that for in-house LSM-YSZ at identical working
condition. SG LSCF showed good short-term
stability with time and under various
polarization potentials. The mechanism and
long-term stability still remains to be developed.
Acknowledgments (optional) I am grateful for the
lab assistant, Mary Smith for her patience,
instruction and consideration. In addition, I
would also like to acknowledge useful discussion
of my lab partner, John Gacia, in the course of
performing this lab..

• References
• Rajiv Doshi, J of the electrochem Soc, 146 (4)
  1273-1278
• Vitalij K. Pecharsky and Peter Y. Zavalij, Kluwer
  Academic Publishers, Fundamentals of Powder
  Diffraction and Structural Characterization of
  Materials, 2003.
• Lab partner, John Gacia
• Lab assistant, Mary Smith