XAFS investigation of [Pd(NH3)4][AuCl 4]2 and its thermolysis products

Article abstract of DOI:10.1007/s10973-010-0723-y

Thermolysis of double complex salt [Pd(NH₃)₄] [AuCl₄]₂ has been studied in helium atmosphere from ambient to 350 °C. The XAFS of Pd K and Au L₃ edges and thermogravimetry measurements have been carrie

Full text of DOI:10.1007/s10973-010-0723-y

J Therm Anal Calorim (2010) 102:703–708
DOI 10.1007/s10973-010-0723-y
XAFS investigation of [Pd(NH ) ][AuCl ] and its thermolysis
3
4
4 2
products
Tatiana Nedoseykina
•
Pavel Plyusnin
•
Yuri Shubin Sergey Korenev
•
Received: 5 November 2009 / Accepted: 10 February 2010 / Published online: 19 March 2010
Ó Akad e´ miai Kiad o´ , Budapest, Hungary 2010
Abstract Thermolysis of double complex salt
Pd(NH ) ][AuCl ] has been studied in helium atmo-
allow preparing single-phase solid solution of different
[
composition. The composition can be easily controlled by a
stoichiometry of the complex precursor. For these reasons
the use of bimetallic molecular clusters as precursors is
considered an attractive alternative to convenient synthesis
methods of bimetallic nanoparticles in Catalysis [6–8].
Other well-crystallized complex salts such as oxalates,
tartrates, and citrates yield mixed oxides on thermal
decomposition at moderate temperatures [9, 10]. Thermal
decomposition is conventional and often used method for
preparing nanoparticles [1–5, 11–16].
3
4
4 2
sphere from ambient to 350 °C. The XAFS of Pd K and Au
L3 edges and thermogravimetry measurements have been
carried out to characterize the intermediates and the final
product. In the temperature range 115–160 °C the complex
is decomposed to form Pd(NH ) Cl and AuCl N spe-
3
2
2
4-x x
cies with x ranging from 2 to 3. Subsequent heating of the
intermediate up to 300 °C leads to the total loss of NH3.
The Au–Cl and Au–Au bonds form the local environment
of Au at the stage of decomposition while only four
chlorine atoms are around Pd. At the temperature of 330 °C
the Au and Pd nanoparticles as well as residues of palla-
dium chloride are detected. The final product consists of
separated Au and Pd nanoparticles.
The investigation of [Pd(NH ) ][AuCl ] thermolysis
3
4
4 2
[16] revealed a dependence of final product on the heating
rate and atmosphere of decomposition. In hydrogen
atmosphere two-phase product Pd0.3Au0.6 and Pd and sin-
gle-phase product Pd0.33Au0.66 are obtained at the heating
rate of 30 °C/min and 15 °C/min, respectively. The
decomposition of the complex in the air and helium
atmospheres results in formation of monometallic particles
Pd and Au. In spite of many investigations on the double
complex salts [2–5, 16] the formation mechanism of
bimetallic and monometallic nanoparticles has not yet been
elucidated to understand the preparative technique for the
control of the particles size and composition. The limited
understanding of these mechanisms deals with, in large
part, the difficulty of characterizing intermediates because
they are often amorphous. XAFS spectroscopy is a unique
method that allows the determination of structure in
amorphous as well crystalline materials. This method
includes two techniques XANES (X-ray Absorption Near
Edge Structure) and EXAFS (Extended X-ray Absorption
Fine Structure) [17, 18]. XANES spectra provide infor-
mation about vacant orbitals, oxidation state, and site
symmetry of the X-ray-excited atoms while EXAFS
spectra yield information on the interatomic distances,
Keywords Thermolysis ꢀ TG ꢀ XAFS ꢀ
Double complex salts ꢀ Nanoparticles
Introduction
In recent years a great deal of attention has been paid to
double complex salts because of their promising applica-
tion as precursors for preparation of bimetallic nanoparti-
cles through the thermal decomposition of these salts [1–5].
The salts have a general formula [M A ] [M B ] , where
1
n x
2 m y
M and M are central metal atoms in the complex cation
1
2
and anion, respectively, A and B are the ligands. This kind
of distribution of the metal atoms in the precursor may
T. Nedoseykina (&) ꢀ P. Plyusnin ꢀ Y. Shubin ꢀ S. Korenev
Nikolaev Institute of Inorganic Chemistry SB RAS, 3, Acad.
Lavrentiev Ave, Novosibirsk, Russia 630090
e-mail: tatianani@list.ru
123

7
04
T. Nedoseykina et al.
variation in the distances (i.e., Debye-Waller factors), the
identity and number of nearest neighboring atoms (coor-
dination numbers) within the first few coordination shells
of the absorption atom.
Fourier transformation (Dk) and fit (DR) ranges are pre-
sented in Table 1 together with the best fits of EXAFS data.
In this article we present Au L and Pd K-edges XAFS
3
Results and discussion
investigation of the [Pd(NH ) ][AuCl ] and its interme-
4 2
3
4
diate products of thermolysis carried out in the helium
atmosphere to enlighten on the thermolysis of this double
complex salt and hence on the formation mechanism of
metallic nanoparticles.
The TG and DTA results of [Pd(NH ) ][AuCl ] presented
3
4
4 2
in Fig. 1 demonstrate three stages of the decomposition at
115–160 °C, 200–290 °C, and 290–330 °C, respectively.
The first stage is accompanied by endoeffect but without a
mass loss. During this stage the compound changes color
from yellow to dark brown. The second and third stages of
the thermolysis are poorly resolved and accompanied by
exothermic and endothermic effects, respectively. The
complex is fully decomposed at 350 °C. For XAFS
investigation, the intermediates were chosen at the ther-
molysis temperatures of 190 (intermediate 1), 300 (inter-
mediate 2) and 330 °C (intermediate 3). The final product
was taken at 350 °C.
Experimental
Initial compounds for a synthesis of the double complex
salt [Pd(NH ) ][AuCl ] were [Pd(NH ) ]Cl , [Pd(NH ) ]
3
4
4 2
3 4
2
3 4
(
NO ) and H[AuCl ]. First [Pd(NH ) ]Cl was synthesized
3 2 4 3 4 2
by procedure described in [19]. Then this compound was
used to prepare [Pd(NH ) ](NO ) by a substitution of
3
4
3 2
chloride ion for nitrate ion. Solution H[AuCl ] was
4
The Au L and Pd K edges XANES spectra of the initial
3
obtained by dissolving of gold (99.99%) in aqua regia and
subsequent boiling down in water and hydrochloric acid.
A required quantity of the solution of H[AuCl4]
complex and its intermediates and the final product of the
thermolysis are depicted in Fig. 2. In the Pd K-edge
XANES spectra the absorption threshold, called the white
line, corresponds to the 1s-4p electron transitions. It is well
known that the intensity and position of the white line are
sensitive to the changes in the electronic occupancy in the
valence orbital and ligand field environments of the
absorbers. Hence, it can be used to estimate the density of
the unoccupied states and the variation in the oxidation
state of the Pd absorber. As it is seen from Fig. 2a, the
white line is slightly decreased in intensity and broadened
as the thermolysis temperature increases from ambient to
300 °C. At the same time, for these spectra no shift of the
white line position is observed. All of these indicate on the
unchangeable Pd oxidation state and changes in the local
(
(
1.0 mol/l) and saturated aqueous solution of [Pd(NH ) ]
3 4
NO ) (0.3 mol/l) were mixed. It immediately led to a
2
3
formation of crystalline precipitation in the form of yellow
needles. The obtained precipitate was filtered off under
vacuum and subsequently washed with minimal quantity
of water, methanol and then air-dried. The yield of
[
Pd(NH ) ][AuCl ] was about 90%.
3 4 4 2
Thermogravimetric (TG) measurements were carried
out on a Q-1000 derivatograph. A test portion of
Pd(NH ) ][AuCl ] was put in a quartz crucible and
[
3
4
4 2
heated with the rate of 10 °C/min in a helium flow (150 ml/
min). Differential thermal analysis (DTA) was carried out
Ò
2?
on an STA 409 PC Luxx (NETZSCH) in the helium
environment of the Pd . In the [Pd(NH ) ][AuCl ]
4 2
3
4
2
complex, the geometry around Pd is square planar. The
?
atmosphere with the heating rate of 5 °C/min.
˚
average Pd–N distance is 2.043 A [16]. For intermediate 2
XAFS spectra at Au L and Pd K edges of the double
3
complex salt and its products of thermolysis were recorded
at the 7C1 Electrochemistry beamline at PAL (Pohang
Accelerator laboratory, Republic of Korea) with ring cur-
rent of 120–170 mA at 2.0 GeV. A Si (111) double-crystal
monochromator with an energy resolution DE/E = 2 9
the XANES spectrum is the closest similar to that of
(NH ) PdCl [22], where the Pd atoms are surrounded by
4
2
4
four chlorine atoms. The Pd spectrum of intermediate 1
looks like the interstitial between the spectra of the initial
complex and intermediate 2. So it can suggest that the local
-
4
2?
1
0
was used. The data acquisition system for XAFS
environment of Pd consists of two N and two Cl atoms.
comprised three ionization detectors measuring beam
The Pd spectra of intermediate 3 and final product resemble
well to that of the Pd metal foil.
intensity of incidence I , transmitted I , and transmitted
0
t
through reference I . The reference channel was employed
r
The white line of the Au L -edge XANES spectra is due
3
primarily for internal calibration of the edge positions by
using pure metal foils. All chambers were filled by nitro-
gen. XAFS spectra recorded in the transition mode were
analyzed and presented here for all the samples. XAFS data
were analyzed by IFFEFIT software package [20, 21].
to the 2p-5d electron transitions and gradually decreases in
intensity going from the initial complex to intermediates 1
and 2 (Fig. 2b). In the Au spectrum of intermediate 2, the
edge position shifts slightly to higher energy and a peak at
11947 eV appears. This peak is typical of the bulk Au foil.
1
23

XAFS investigation of [Pd(NH
3
)
4
][AuCl
4
]
2
705
3 4 4 2
Table 1 EXAFS parameters for [Pd(NH ) ][AuCl ] and its thermolysis products
2
2
2
0
3
˚
/A C
4
-1
˚
R/A
˚
˚
/A
˚
˚
T/°C
Bonds
CN
r /A
DE
0
/eV
S
C
3
4
F/%
Dk/A DR/A
2
1
3
3
4
Pd–N
Pd–N
Au–Cl
2.0(1)
2.046(7)
2.054(7)
2.284(7)
0.0021(9)
0.0021(3)
0.5(9)
10(1)
6.7(6)
10(1)
3.5(7)
9(1)
0.8
0.8
0.8
0.8
0.8
0.8
0.6
1.0
2.5–10.0
1.0–2.2
3.1–14
2.0(1)
4.0(1)
0.9
0.2
0.9
0.3
1.1
1.7
1
.0–2.4
90
00
30
Pd–N
Pd–Cl
Au–N
Au–Cl
Pd–Cl
2.0(3)
2.0(3)
1.4(3)
2.6(6)
3.8(4)
2.041(3)
2.334(6)
2.029(9)
2.285(8)
2.315(9)
0.002(2)
0.0013(8)
0.002(2)
0.0013(5)
0.003(1)
2.9–12.0
1.0–2.4
2.8–14.0
1.0–2.4
3.0–12.0
1
.0–2.4
Au–Cl
Au–Au
Pd–Cl
2.2(3)
3(1)
2.283(7)
2.89(2)
0.001(1)
0.006(3)
0.002(1)
0.0067(2)
0.010(3)
0.0083(8)
0.010(1)
0.012(1)
0.013(2)
0.0048(2)
0.0082(3)
0.0085(3)
0.0096(1)
0.012(2)
0.013(1)
2.8–12.0
1.0–3.3
2.9–12.0
1.5–5.5
-
4
1.2(3)
11.0(5)
5.6(2)
2.5(9)
11.8(6)
5.9(3)
24(1)
2.290(9)
2.750(3)
3.889(4)
4.764(4)
2.879(5)
4.072(7)
4.988(8)
2.750(4)
3.890(5)
4.764(7)
2.882(7)
4.075(9)
4.991(1)
0.0(3)
1(1)*10
Pd–Pd
Pd–Pd
Pd–Pd
Au–Au
Au–Au
Au–Au
Pd–Pd
Pd–Pd
Pd–Pd
Au–Au
Au–Au
Au–Au
-
4
5
5.8(4)
2.1(4)
6.0(3)
2.6(8)*10
5(3)*10
2.8–12.5
1.8–6.0
-
0.6
0.6
0.9
0.6
-4
3
50
12.0(4)
6.0(2)
24.0(6)
11.8(3)
5.9(2)
23.5(6)
1.2(5)*10
2.9–12.0
1.0–5.5
-
4
5
0.6
2.5(7)*10
5(2)*10
0.6
2.8–12.0
1.9–5.6
-
2
2
0
CN coordination number, R interatomic distance, r Debye-Waller factor, DE
0
correction of the absorption edge position, S
electron amplitude
reduction factor, C
3
4
and C are the third and forth cumulants (a measure of the deviation of Pair Distribution Function from the Gaussian shape
[17, 18]), F quality of the fit (characterizes differences between theoretical and experimental data [17]), Dk Fourier transformation range, and DR
fit range
3
?
the edge position for Au is ascribed to an intensive and
poorly resolved pre-edge peak [23]. Thus, at the tempera-
Exo 100
TG
9
8
7
6
5
4
3
2
1
0
0
0
0
0
0
0
0
0
3
?
ture of 300 °C, it occurs as a partial reduction of Au to
Au . The Au spectra of intermediate 3 and final product are
0
similar to that of the Au metal foil indicating the formation
of the gold particles.
DTA
The Fourier transformed (FT) EXAFS spectra at the Au
L3 (Au-FT) and Pd K edges (Pd-FT) are shown in Fig. 3.
˚
For the initial complex a single peak at 1.5 A in the Pd-FT
˚
and at 1.9 A in the Au-FT is attributed to Pd–N and Au–Cl
5
0
100
150
200
250
300
350
400
coordination shell, respectively. By increasing the ther-
Temperature/°C
molysis temperature to 190 °C, the Pd-FT and Au-FT show
˚
˚
Fig. 1 TG and DTA curves of [Pd(NH
show the temperatures at which the products were chosen for the
study
3
)
4
][AuCl
4
]
2
. Vertical bars
the peak with maximum at 1.9 A and a shoulder at 1.6 A.
Additionally, the Au-FT peak decreases in magnitude. It
can be ascribed to the decrease in the number of Cl atoms
and/or appearance of N atoms in the first coordination shell
of Au. The shoulder of the Pd-FT peak agrees with the Pd–
N peak of the initial DCS. All of these might suggest a
model where Pd and Au atoms are surrounded by nitrogen
Here, it is necessary to remind that the Au L edge position
3
shifts to the higher energy as far as the Au oxidation state
3
changes from Au to Au and Au . The unusual shift of
?
0
1?
123

7
06
T. Nedoseykina et al.
3
Fig. 2 Pd K (a) and Au L (b)
(
b)
(
a)
edges XANES of the initial
complex and its thermolysis
products
Au foil
Pd foil
final product (350°C)
final product (350°C)
intermediate 3 (330°C)
intermediate 3 (330°C)
intermediate 2 (300°C)
intermediate 1 (190°C)
intermediate 2 (300°C)
intermediate 1 (190°C)
[
Pd(NH ) ][AuCl ]
3 4 4 2
[
Pd(NH ) ][AuCl ]
3 4 4 2
2
4320
24360
24400
24440
24480
11900 11920 11940 11960 11980 12000
Photon energy/eV
Photon energy/eV
Fig. 3 Fourier transformations
2
(a)
(b)
of experimental k v(k) Pd K and
final product (350°C)
3
Au L edges EXAFS (solid
curves) and fits (dots curves) of
the initial complex and its
thermolysis products. Here, r is
the interatomic distance to
within the phase-shift correction
intermediate 3 (330°C)
final product (350°C)
intermediate 3 (330°C)
(
d)
χ
χ
intermediate 2 (300°C)
intermediate 2 (300°C)
intermediate 1 (190°C)
intermediate 1 (190°C)
[
Pd(NH ) ][AuCl ]
[
Pd(NH ) ][AuCl ]
3 4 4 2
3
4
4 2
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
r/Å
r/Å
˚
Main peak at 1.9 A is observed in the Pd-FT and Au-FT
and chlorine atoms. The use of such model as the initial
one in the fitting procedure of the EXAFS spectrum gives a
good result (Table 1). Indeed, the first coordination shell of
Pd consists of two N and two Cl atoms at distances 2.04
of intermediate 2. From the fitting procedure of Pd K and
Au L edges EXAFS spectra it was found that this peak
3
corresponds to a coordination shell consisting of chlorine
˚
and 2.33 A, respectively. In the first coordination shell of
atoms. For the best fit of the Au L -edge EXAFS for this
3
Au, 1.4 Cl and 2.6 N atoms are found at distances 2.03 and
˚
intermediate, the contribution from Au-Au was taken into
˚
account. Thus, there are two chlorine atoms at 2.28 A and
2
.29 A, respectively. As it was assumed in [16], the
˚
three gold atoms at 2.89 A in the local environment of Au.
intermediate of the thermolysis stage consists of amor-
phous compounds Pd(NH ) Cl and Au(NH )Cl . This
As mentioned above, the XANES spectra of both the Au
L3 and Pd K edges for intermediate 3 and final product are
similar to those of the corresponding metal foils. However,
the Au- and Pd-FTs show a reduced magnitude of all peaks
compared to those of the corresponding metal foils, i.e., the
3
2
2
3
3
assumption is mainly confirmed by both XANES and
EXAFS. However, the obtained coordination numbers
(
CN) for Au–N and Au–Cl indicate a coexistence of the
Au(NH )Cl and Au(NH ) Cl phases.
3
3
3 2
2
1
23

XAFS investigation of [Pd(NH
3
)
4
][AuCl
4
]
2
707
0
reduced amplitude of EXAFS oscillations. It can be caused
by a strong disorder in material, particles size and thickness
effect [24]. In our research, intermediate 3 and final product
were also studied by XRD. Additionally, TEM (transmis-
sion electron microscopy) was used to estimate size of
particles in the final product. (XRD and TEM data are not
shown). The estimation of particles size by both methods
gave around 10 and 20 nm for Pd and Au particles,
respectively. In this case, the coordination number of the
first shell around Au and Pd should be 12 atoms. We
measured EXAFS spectrum of Pd metal powder and
revealed that the spectrum also has the reduced amplitude of
formation concurrently occurs with association of Au
1
?
0
atoms when the reduction of Au species to Au atoms
proceeds and finishes at the temperature of 330 °C. The
formation of Pd particles is going through the reduction of
2
?
0
Pd to Pd and finishes at 350 °C.
The obtained final product consisting of monometallic
Pd and Au particles is probably due to that the Pd and Au
atoms nucleate at different temperatures. The latter origi-
nates from Pd and Au species formed at the first stage
(Pd(NH ) Cl and AuCl N species). Thus, for the pre-
3
2
2
4-x x
paring of bimetallic nanoparticles, the first stage should be
suppressed. It can be done by changing the decomposition
atmosphere from inert to reduction one. Thermal decom-
position of [Pd(NH ) ][AuCl ] in hydrogen atmosphere is
EXAFS oscillations. The reasonable coordination numbers
2
(
CN = 12) can be obtained only if parameter S , electron
0
3 4
4 2
amplitude reduction factor, decreases up to 0.6. Using this
sample as a reference for the last products of the thermol-
ysis, the EXAFS parameters were found for them (Table 1).
We consider in our case the thickness is the main effect
determining the decrease in the EXAFS amplitude.
under study.
Conclusions
The intermediates and final product of the thermolysis of
[Pd(NH ) ][AuCl ] were studied by the Au L and Pd K
Discussion of thermolysis formation of metallic
nanoparticles
3
4
4 2
3
edges XAFS. Main stages of the thermal decomposition of
the complex can be described as following. On the first
stage, ligands rearrangement and breakdown of the com-
plex happen. The second stage is characterized by the total
Thermolysis of the double complex salt, [Pd(NH ) ]
4
3
[
AuCl ] , carried out in helium atmosphere from ambient
4 2
3
?
2?
to 350 °C results in the reduction of Au and Pd to their
zero-valent metal nanoparticles. This process starts from a
ligand exchange between complex cation and anion of the
loss of NH ligands and beginning of the Au-nanoparticles
3
formation. The product of the third stage consists of the Au
and Pd nanoparticles as well as residues of palladium
chloride. Separated Au and Pd particles form the final
product of the thermolysis at the temperature of 350 °C.
initial complex. The Au L and Pd K edges XANES spectra
3
of intermediate 1, having no significant changes as com-
pared with the initial complex, indicate that the oxidation
states of Au and Pd remain to be 3 and 2, respectively. The
EXAFS data (Table 1 and Fig. 2) show variations in the
identity and number of the nearest neighboring atoms
around Pd and Au atoms in intermediate 1 (190 °C). The
Acknowledgements This study was financially supported by the
interdisciplinary project of fundamental research SB RAS N112, and
by RFBR grants 08-03-00603-a and NSh-636.2008.3.
found coordination number of Au–Cl (2.6) and Au–N (1.4)
-
indicates the total or partial transformation of AuCl to
References
4
-
AuCl4-x(NH ) species with x ranging from 2 to 3. The
larger value of CN of Au–Cl might be explained by the
3 x
1
. Korenev SV, Venediktov AB, Shubin YV, Gromilov SA, Yu-
senko KV. Synthesis and structure of binary complexes of plat-
inum group metals—precursors of metallic materials. J Struct
Chem. 2003;44:46–59.
-
domination of the AuCl (NH ) species in the intermedi-
3
3
ate. The coordination numbers of Pd–N and Pd–Cl match
well to these of Pd(NH ) Cl . Besides the observed ligand
2
. Shubin YV, Filatov EY, Baidina IA. Synthesis of
3
2
2
[
M(NH
of thermolysis products. Crystal structure of [Rh(NH
ReO . J Struct Chem. 2006;47:1103–10.
3. Shubin YV, Zadesenets AV, Venediktov AB. Double complex
3
)
5
Cl](ReO
4
)
2
(M = Cr, Co, Ru, Rh, Ir) and investigation
exchange, there is also a partial loss of NH by the initial
3
3 5
) Cl]
complex. The total loss of the ammonia molecules happens
at the temperature higher than 300 °C. At the decomposi-
tion temperature of 300 °C, the contribution of the Au–Cl
bond still remains dominant though its coordination num-
ber decreases down to 2.2 and CN of Au–Au metallic bond
increases up to 3. Taking into account the CN for Au–Cl
(
4 2
)
0
0
salts [M(NH3)5Cl][M Br4] (M = Rh, Ir, Co, Cr, Ru; M = Pt,
Pd): synthesis, X-ray diffraction characterization, and thermal
properties. Russ J Inorg Chem. 2006;51:202–9.
4
. Zadesenets AV, Venediktov AB, Shubin YV. [Zn(NH
and [Cd(NH ][PtCl ] as precursors for intermetallic compounds
PtZn and PtCd. Russ J Inorg Chem. 2007;52:500–4.
3 4 6
) ][PtCl ]
3
)
4
6
and described above peculiarities in the Au L -XANES
3
0
spectrum for intermediate 2, we think that the Au and
5. Yusenko KV, Filatov EY, Vasilchenko DB, Baidina IA, Zades-
enez AV, Shubin YV. Synthesis and thermal decomposition of
the oxalatho cuprates(II)-[M(NH3)(4)] [Cu(C2O4)(2)]*3H(2)O,
M = Pt, Pd. Z Kristallogr. 2007;26(Suppl):289–95.
1
Au are main states presented in this intermediate. Some
?
3?
amount of Au is also possible. Thus, the Au particles
123

7
08
T. Nedoseykina et al.
6
. Nashner MS, Somerville DM, Lane PD, Adler DL, Shapley JR,
Nuzzo RG. Bimetallic catalyst particle nanostructure. Evolution
from molecular cluster precursors. J Am Chem Soc. 1996;118:
15. Boldyrev VV. Thermal decomposition of silver oxalate. Ther-
mochim Acta. 2002;388:63–90.
16. Plyusnin PE, Baidina IA, Shubin YV, Korenev SV. Synthesis,
1
2964–74.
crystal structure, and thermal properties of [Pd(NH
Russ J Inorg Chem. 2007;52:371–7.
17. Koningsberger DC, Prins R, editors. X-Ray absorption: princi-
ples, applications, techniques of EXAFS, SEXAFS and XANES.
New York: John Wiley & Sons; 1988.
18. Crozier ED. A review of the current status of XAFS spectros-
copy. Nucl Instrum Methods Phys Res Sect B. 1997;133:134–44.
19. Chernyaeva II. Synthesis of complex compounds of Platinum
group metals. Moscow: Nauka; 1964. (in Russian).
20. Ravel B, Newville M. ATHENA, ARTEMIS, HEPHAESTUS:
data analysis for X-ray absorption spectroscopy using IFEFFIT. J
Synchrotron Rad. 2005;12:537–41.
3 4 4 2
) ][AuCl ] .
7
8
. Gates BC. Supported metal cluster: Synthesis, structure, and
catalysis. Chem Rev. 1995;95:511–22.
. Nashner MS, Frenkel AI, Adler DL, Shapley JR, Nuzzo RG.
Structural characterization of carbon-supported platinum-ruthe-
nium nanoparticles from the molecular cluster precursor
5
PtRu C(CO)16. J Am Chem Soc. 1997;119:7760–71.
9
. Pocol V, Patrol L, Carp O, Brezeanu M, Segal E, Stanica N, et al.
Some polynuclear coordination compounds precursors of chr-
omites: synthesis, physicochemical characterization and thermal
stability. J Therm Anal Calorim. 1999;55:143–54.
0. Delmon B. Preparation of heterogeneous catalysts: synthesis of
highly dispersed solids and their reactivity. J Therm Anal Calo-
rim. 2007;90:49–65.
1
1
1
21. Newville M. IFEFFIT: interactive XAFS analysis and FEFF fit-
ting. J Synchrotron Rad. 2001;8:322–4.
1. Bakrania SD, Rathore GK, Wooldridge MS. An investigation of
the thermal decomposition of gold acetate. J Therm Anal Calo-
rim. 2009;95:117–22.
2. Lucca Neto VA, Mauro AE, Netto AVG, Moro AC, Noguera
VM. Mono and dinuclear Pd(II) complexes pyrazole and imid-
azole-type ligands. Synthesis, characterization and thermal
behavior. J Therm Anal Calorim. 2009;97:57–60.
3. Salavati-Niasari M, Davar F. Synthesis of copper and copper(I)
oxide nanoparticles by thermal decomposition of a new precur-
sor. Mater Lett. 2009;63:441–3.
4. Liu X, Lu S, Zhang J, Cao W. Thermal decomposition process of
silver behenate. Thermochim Acta. 2006;440:1–6.
22. Sobczak JW, Sobczak E, Kosi n´ ski A, Bili n´ ski A. XANES
investigations of Pd-doped polyaniline. J Alloys Compd. 2001;
328:132–4.
23. Berrodier I, Farges F, Benedetti M, Winterer M, Brown GE,
Deveughele M. Adsorption mechanisms of trivalent gold on iron-
and aluminum-(oxy)hydroxides. Part 1: X-ray absorption and
Raman scattering spectroscopic studies of Au(III) adsorbed on
ferrihydrite, goethite, and boehmite. Geochim Cosmochim Acta.
2004;68:3019–42.
1
1
24. Stern EA, Kim K. Thickness effect on the extended-X-ray-
absorption-fine-structure amplitude. Phys Rev B. 1981;23:3781–7.
1
23