A 200 W CO2 laser-based heating system coupled with in operando Raman spectroscopy has been developed. The system delivers highly concentrated radiation capable of driving thermochemical reactions and simulates heat fluxes expected by 3D solar concentrating systems. 10 mol% Gd-doped and pure ceria pellets were prepared and used to characterize the system because of their well-established thermodynamic and kinetic properties, as well as their strong Raman peak due to F2 g symmetrical mode at 460 cm−1. Reduction in an H2 atmosphere has been carried out to investigate the behavior of the full width at half maximum (FWHM) of the F2 g Raman peak resulting from changes in temperature and oxidation state. For both samples, an increase in temperature during heating in air (i.e., fully oxidized) resulted in a peak shift toward low wavenumber and an increase of FWHM. The FWHM versus temperature curves were then measured for controlled reduction extents ranging between sample averaged nonstoichiometries of δ = 0–0.209 as a function of temperature. At a fixed temperature, Gd-doped ceria exhibited an increase in FWHM with increasing reduction extent until δ = 0.056. At greater reduction extents, the FWHM decreased with increasing reduction extents. We attribute this to changes in the lattice parameter caused by the eventual formation of intermediate cubic Ce2O3 at the radiated surface. This study demonstrates the promise of utilizing Raman spectroscopy to probe thermochemical reactions in operando. Going forward, we expect that this will be an especially promising tool for characterizing emerging thermochemical materials with complex phase equilibria, especially for nonequilibrium processes.

References

References
1.
Concepcion
,
J.
,
House
,
R.
,
Papanikolas
,
J.
, and
Meyer
,
T.
,
2012
, “
Chemical Approaches to Artificial Photosynthesis
,”
Proc. Natl. Acad. Sci. U. S. A.
,
109
(
39
), pp.
15560
15564
.
2.
Blankenship
,
R.
,
Tiede
,
D.
,
Barber
,
J.
,
Brudvig
,
G.
,
Fleming
,
G.
,
Ghirardi
,
M.
,
Gunner
,
M.
,
Junge
,
W.
,
Kramer
,
D.
,
Melis
,
A.
,
Moore
,
T.
,
Moser
,
C.
,
Nocera
,
D.
,
Nozik
,
A.
,
Ort
,
D.
,
Parson
,
W.
,
Prince
,
R.
, and
Sayre
,
R.
,
2011
, “
Comparing Photosynthetic and Photovoltaic Efficiencies and Recognizing the Potential for Improvement
,”
Science
,
332
(
6031
), pp.
805
809
.
3.
Kodama
,
T.
, and
Gokon
,
N.
,
2007
, “
Thermochernical Cycles for High-Temperature Solar Hydrogen Production
,”
Chem. Rev.
,
107
(
10
), pp.
4048
4077
.
4.
Romero
,
M.
, and
Steinfeld
,
A.
,
2012
, “
Concentrating Solar Thermal Power and Thermochemical Fuels
,”
Energy Environ. Sci.
,
5
(
11
), pp.
9234
9245
.
5.
Schulz
,
H.
,
1999
, “
Short History and Present Trends of Fischer-Tropsch Synthesis
,”
Appl. Catal., A
,
186
(
1–2
), pp.
3
12
.
6.
Riedel
,
T.
,
Schulz
,
H.
,
Schaub
,
G.
,
Jun
,
K.
,
Hwang
,
J.
, and
Lee
,
K.
,
2003
, “
Fischer-Tropsch on Iron With H-2/CO and H-2/CO2 as Synthesis Gases: The Episodes of Formation of the Fischer-Tropsch Regime and Construction of the Catalyst
,”
Top. Catal.
,
26
(
1–4
), pp.
41
54
.
7.
Omar
,
S.
,
Wachsman
,
E.
,
Jones
,
J.
, and
Nino
,
J.
,
2009
, “
Crystal Structure-Ionic Conductivity Relationships in Doped Ceria Systems
,”
J. Am. Ceram. Soc.
,
92
(
11
), pp.
2674
2681
.
8.
Teocoli
,
F.
, and
Esposito
,
V.
,
2014
, “
Viscoelastic Properties of Doped-Ceria Under Reduced Oxygen Partial Pressure
,”
Scr. Mater.
,
75
, pp.
82
85
.
9.
Chueh
,
W.
, and
Haile
,
S.
,
2010
, “
A Thermochemical Study of Ceria: Exploiting an Old Material for New Modes of Energy Conversion and CO2 Mitigation
,”
Philos. Trans. R. Soc. A
,
368
(
1923
), pp.
3269
3294
.
10.
Gopal
,
C.
, and
Haile
,
S.
,
2014
, “
An Electrical Conductivity Relaxation Study of Oxygen Transport in Samarium Doped Ceria
,”
J. Mater. Chem. A
,
2
(
7
), pp.
2405
2417
.
11.
Chueh
,
W.
, and
Haile
,
S.
,
2009
, “
Ceria as a Thermochemical Reaction Medium for Selectively Generating Syngas or Methane From H2O and CO2
,”
Chemsuschem
,
2
(
8
), pp.
735
739
.
12.
Marxer
,
D.
,
Furler
,
P.
,
Takacs
,
M.
, and
Steinfeld
,
A.
,
2017
, “
Solar Thermochemical Splitting of CO2 Into Separate Streams of CO and O-2 With High Selectivity, Stability, Conversion, and Efficiency
,”
Energy Environ. Sci.
,
10
(
5
), pp.
1142
1149
.
13.
McDaniel
,
A.
,
Miller
,
E.
,
Arifin
,
D.
,
Ambrosini
,
A.
,
Coker
,
E.
,
O'Hayre
,
R.
,
Chueh
,
W.
, and
Tong
,
J.
,
2013
, “
Sr- and Mn-Doped LaAlO3-Delta for Solar Thermochemical H-2 and CO Production
,”
Energy Environ. Sci.
,
6
(
8
), pp.
2424
2428
.
14.
Chueh
,
W.
,
Falter
,
C.
,
Abbott
,
M.
,
Scipio
,
D.
,
Furler
,
P.
,
Haile
,
S.
, and
Steinfeld
,
A.
,
2010
, “
High-Flux Solar-Driven Thermochemical Dissociation of CO2 and H2O Using Nonstoichiometric Ceria
,”
Science
,
330
(
6012
), pp.
1797
1801
.
15.
Furler
,
P.
,
Scheffe
,
J.
, and
Steinfeld
,
A.
,
2012
, “
Syngas Production by Simultaneous Splitting of H2O and CO2 Via Ceria Redox Reactions in a High-Temperature Solar Reactor
,”
Energy Environ. Sci.
,
5
(
3
), pp.
6098
6103
.
16.
Ackermann
,
S.
,
Sauvin
,
L.
,
Castiglioni
,
R.
,
Rupp
,
J.
,
Scheffe
,
J.
, and
Steinfeld
,
A.
,
2015
, “
Kinetics of CO2 Reduction Over Nonstoichiometric Ceria
,”
J. Phys. Chem. C
,
119
(
29
), pp.
16452
16461
.
17.
Takacs
,
M.
,
Scheffe
,
J.
, and
Steinfeld
,
A.
,
2015
, “
Oxygen Nonstoichiometry and Thermodynamic Characterization of Zr Doped Ceria in the 1573–1773 K Temperature Range
,”
Phys. Chem. Chem. Phys.
,
17
(
12
), pp.
7813
7822
.
18.
Warren
,
K.
, and
Scheffe
,
J.
,
2018
, “
Kinetic Insights Into the Reduction of Ceria Facilitated Via the Partial Oxidation of Methane
,”
Mater. Today Energy
,
9
, p.
10
.
19.
Chueh
,
W.
,
McDaniel
,
A.
,
Grass
,
M.
,
Hao
,
Y.
,
Jabeen
,
N.
,
Liu
,
Z.
,
Haile
,
S.
,
McCarty
,
K.
,
Bluhm
,
H.
, and
El Gabaly
,
F.
,
2012
, “
Highly Enhanced Concentration and Stability of Reactive Ce3+ on Doped CeO2 Surface Revealed in Operando
,”
Chem. Mater.
,
24
(
10
), pp.
1876
1882
.
20.
Bonk
,
A.
,
Maier
,
A.
,
Schlupp
,
M.
,
Burnat
,
D.
,
Remhof
,
A.
,
Delmelle
,
R.
,
Steinfeld
,
A.
, and
Vogt
,
U.
,
2015
, “
The Effect of Dopants on the Redox Performance, Microstructure and Phase Formation of Ceria
,”
J. Power Sources
,
300
, pp.
261
271
.
21.
Coker
,
E.
,
Ambrosini
,
A.
,
Rodriguez
,
M.
, and
Miller
,
J.
,
2011
, “
Ferrite-YSZ Composites for Solar Thermochemical Production of Synthetic Fuels: In Operando Characterization of CO2 Reduction
,”
J. Mater. Chem.
,
21
(
29
), pp.
10767
10776
.
22.
Lai
,
W.
, and
Haile
,
S.
,
2005
, “
Impedance Spectroscopy as a Tool for Chemical and Electrochemical Analysis of Mixed Conductors: A Case Study of Ceria
,”
J. Am. Ceram. Soc.
,
88
(
11
), pp.
2979
2997
.
23.
Xie
,
S.
,
Iglesia
,
E.
, and
Bell
,
A.
,
2001
, “
Effects of Temperature on the Raman Spectra and Dispersed Oxides
,”
J. Phys. Chem. B
,
105
(
22
), pp.
5144
5152
.
24.
Santoro
,
M.
,
Lin
,
J.
,
Mao
,
H.
, and
Hemley
,
R.
,
2004
, “
In Situ High P-T Raman Spectroscopy and Laser Heating of Carbon Dioxide
,”
J. Chem. Phys.
,
121
(
6
), pp.
2780
2787
.
25.
Weber
,
W. H.
,
Hass
,
K. C.
, and
McBride
,
J. R.
,
1993
, “
Raman-Study of Ceo2—2nd-Order Scattering, Lattice-Dynamics, and Particle-Size Effects
,”
Phys. Rev. B
,
48
(
1
), pp.
178
185
.
26.
McBride
,
J. R.
,
Hass
,
K. C.
,
Poindexter
,
B. D.
, and
Weber
,
W. H.
,
1994
, “
Raman and X-Ray Studies of Ce1-XREXO2-Y, Where Re=LA, PR, ND, EU, GD, AND Tb
,”
J. Appl. Phys.
,
76
(
4
), pp.
2435
2441
.
27.
Rupp
,
J.
,
Scherrer
,
B.
, and
Gauckler
,
L.
,
2010
, “
Engineering Disorder in Precipitation-Based Nano-Scaled Metal Oxide Thin Films
,”
Phys. Chem. Chem. Phys.
,
12
(
36
), pp.
11114
11124
.
28.
Maher
,
R.
, and
Cohen
,
L.
,
2008
, “
Raman Spectroscopy as a Probe of Temperature and Oxidation State for Gadolinium-Doped Ceria Used in Solid Oxide Fuel Cells
,”
J. Phys. Chem. A
,
112
(
7
), pp.
1497
1501
.
29.
Kanakaraju
,
S.
,
Mohan
,
S.
, and
Sood
,
A.
,
1997
, “
Optical and Structural Properties of Reactive Ion Beam Sputter Deposited CeO2 Films
,”
Thin Solid Films
,
305
(
1–2
), pp.
191
195
.
30.
Wang
,
J.
,
Tai
,
Y.
,
Dow
,
W.
, and
Huang
,
T.
,
2001
, “
Study of Ceria-Supported Nickel Catalyst and Effect of Yttria Doping on Carbon Dioxide Reforming of Methane
,”
Appl. Catal., A
,
218
(
1–2
), pp.
69
79
.
31.
Escribano
,
V.
,
Lopez
,
E.
,
Panizza
,
M.
,
Resini
,
C.
,
Amores
,
J.
, and
Busca
,
G.
,
2003
, “
Characterization of Cubic Ceria-Zirconia Powders by X-Ray Diffraction and Vibrational and Electronic Spectroscopy
,”
Solid State Sci.
,
5
(
10
), pp.
1369
1376
.
32.
Stelzer
,
N.
,
Nolting
,
J.
, and
Riess
,
I.
,
1995
, “
Phase-Diagram of Nonstoichiometric 10 Mol-Percent Gd2o3-Doped Cerium Oxide Determined From Specific-Heat Measurements
,”
J. Solid State Chem.
,
117
(
2
), pp.
392
397
.
33.
Dohcevic-Mitrovic
,
Z.
,
Scepanovic
,
M.
,
Grujic-Brojcin
,
M.
,
Popovic
,
Z.
,
Boskovic
,
S.
,
Matovic
,
B.
,
Zinkevich
,
M.
, and
Aldinger
,
F.
,
2006
, “
The Size and Strain Effects on the Raman Spectra of Ce1-xNdxO2-Delta (0 <= x <= 0.25) Nanopowders
,”
Solid State Commun.
,
137
(
7
), pp.
387
390
.
34.
Lin
,
X.
,
Li
,
L.
,
Li
,
G.
, and
Su
,
W.
,
2001
, “
Transport Property and Raman Spectra of Nanocrystalline Solid Solutions Ce0.8Nd0.2O2-Delta With Different Particle Size
,”
Mater. Chem. Phys.
,
69
(
1–3
), pp.
236
240
.
35.
Taniguchi
,
T.
,
Watanabe
,
T.
,
Sugiyama
,
N.
,
Subramani
,
A.
,
Wagata
,
H.
,
Matsushita
,
N.
, and
Yoshimura
,
M.
,
2009
, “
Identifying Defects in Ceria-Based Nanocrystals by UV Resonance Raman Spectroscopy
,”
J. Phys. Chem. C
,
113
(
46
), pp.
19789
19793
.
36.
Chandradass
,
J.
,
Nam
,
B.
, and
Kim
,
K.
,
2009
, “
Fine Tuning of Gadolinium Doped Ceria Electrolyte Nanoparticles Via Reverse Microemulsion Process
,”
Colloids Surf., A
,
348
(
1–3
), pp.
130
136
.
37.
Guo
,
M.
,
Lu
,
J.
,
Wu
,
Y.
,
Wang
,
Y.
, and
Luo
,
M.
,
2011
, “
UV and Visible Raman Studies of Oxygen Vacancies in Rare-Earth-Doped Ceria
,”
Langmuir
,
27
(
7
), pp.
3872
3877
.
38.
Nakajima
,
A.
,
Yoshihara
,
A.
, and
Ishigame
,
M.
,
1994
, “
Defect-Induced Raman-Spectra in Doped Ceo2
,”
Phys. Rev. B
,
50
(
18
), pp.
13297
13307
.
39.
Mandal
,
B.
,
Grover
,
V.
,
Roy
,
M.
, and
Tyagi
,
A.
,
2007
, “
X-Ray Diffraction and Raman Spectroscopic Investigation on the Phase Relations in Yb2O3- and Tm2O3-Substituted CeO2
,”
J. Am. Ceram. Soc.
,
90
(
9
), pp.
2961
2965
.
40.
Lee
,
Y.
,
He
,
G.
,
Akey
,
A.
,
Si
,
R.
,
Flytzani-Stephanopoulos
,
M.
, and
Herman
,
I.
,
2011
, “
Raman Analysis of Mode Softening in Nanoparticle CeO2-Delta and Au-CeO2-Delta During CO Oxidation
,”
J. Am. Chem. Soc.
,
133
(
33
), pp.
12952
12955
.
41.
Klemens
,
P.
,
1966
, “
Anharmonic Decay of Optical Phonons
,”
Phys. Rev.
,
148
(
2
), p.
845
.
42.
Balkanski
,
M.
,
Wallis
,
R.
, and
Haro
,
E.
,
1983
, “
Anharmonic Effects in Light-Scattering Due to Optical Phonons in Silicon
,”
Phys. Rev. B
,
28
(
4
), pp.
1928
1934
.
43.
Walrafen
,
G.
,
Fisher
,
M.
,
Hokmabadi
,
M.
, and
Yang
,
W.
,
1986
, “
Temperature-Dependence of the Low-Frequency Nd High-Frequency Raman-Scattering from Liquid Water
,”
J. Chem. Phys.
,
85
(
12
), pp.
6970
6982
.
44.
Dohcevic-Mitrovic
,
Z.
,
Radovic
,
M.
,
Scepanovic
,
M.
,
Grujic-Brojcin
,
M.
,
Popovic
,
Z.
,
Matovic
,
B.
, and
Boskovic
,
S.
,
2007
, “
Temperature-Dependent Raman Study of Ce0.75Nd0.25O2-Delta Nanocrystals
,”
Appl. Phys. Lett.
,
91
(
20
), pp. 203118-1–203118-3.
45.
Cowley
,
R.
,
1965
, “
Raman Scattering From Crystals of Diamond Structure
,”
J. Phys. Arch.
,
26
(
11
), p.
659
.
46.
Pine
,
A.
, and
Tannenwald
,
P.
,
1969
, “
Temperature Dependence of Raman Linewidth and Shift in Alpha-Quartz
,”
Phys. Rev.
,
178
(
3
), p.
1424
.
47.
Spanier
,
J.
,
Robinson
,
R.
,
Zheng
,
F.
,
Chan
,
S.
, and
Herman
,
I.
,
2001
, “
Size-Dependent Properties of CeO2-y Nanoparticles as Studied by Raman Scattering
,”
Phys. Rev. B
,
64
(
24
), pp. 245407-1–245407-8.
48.
Richter
,
H.
,
Wang
,
Z.
, and
Ley
,
L.
,
1981
, “
The One Phonon Raman-Spectrum in Microcrystalline Silicon
,”
Solid State Commun.
,
39
(
5
), pp.
625
629
.
49.
Ban
,
Y.
, and
Nowick
,
A. S.
,
1972
, “
Defects and Mass Transport in Reduced CeO2 Single Crystals
,”
Fifth Materials Research Symposium
, Gaithersburg, MD, Oct. 18, p.
13
.
50.
Ackermann
,
S.
, and
Steinfeld
,
A.
,
2017
, “
Spectral Hemispherical Reflectivity of Nonstoichiometric Cerium Dioxide
,”
Sol. Energy Mater. Sol. Cells
,
159
, pp.
167
171
.
51.
Maher
,
R.
,
Shearing
,
P.
,
Brightman
,
E.
,
Brett
,
D.
,
Brandon
,
N.
, and
Cohen
,
L.
,
2016
, “
Reduction Dynamics of Doped Ceria, Nickel Oxide, and Cermet Composites Probed Using In Situ Raman Spectroscopy
,”
Adv. Sci.
,
3
(
1
), pp. 1500146-1–1500146-8.
52.
Kosacki
,
I.
,
Suzuki
,
T.
,
Anderson
,
H.
, and
Colomban
,
P.
,
2002
, “
Raman Scattering and Lattice Defects in Nanocrystalline CeO2 Thin Films
,”
Solid State Ion.
,
149
(
1–s2
), pp.
99
105
.
53.
Tsunekawa
,
S.
,
Sivamohan
,
R.
,
Ito
,
S.
,
Kasuya
,
A.
, and
Fukuda
,
T.
,
1999
, “
Structural Study on Monosize CeO2-x Nano-Particles
,”
Nanostructured Mater.
,
11
(
1
), pp.
141
147
.
54.
Zhang
,
F.
,
Chan
,
S.
,
Spanier
,
J.
,
Apak
,
E.
,
Jin
,
Q.
,
Robinson
,
R.
, and
Herman
,
I.
,
2002
, “
Cerium Oxide Nanoparticles: Size-Selective Formation and Structure Analysis
,”
Appl. Phys. Lett.
,
80
(
1
), pp.
127
129
.
55.
Wu
,
L. J.
,
Wiesmann
,
H. J.
,
Moodenbaugh
,
A. R.
,
Klie
,
R. F.
,
Zhu
,
Y. M.
,
Welch
,
D. O.
, and
Suenaga
,
M.
,
2004
, “
Oxidation State and Lattice Expansion of CeO2-x Nanoparticles as a Function of Particle Size
,”
Phys. Rev. B
,
69
(
12
), pp. 125415-1–125415-9.
56.
Deshpande
,
S.
,
Patil
,
S.
,
Kuchibhatla
,
S.
, and
Seal
,
S.
,
2005
, “
Size Dependency Variation in Lattice Parameter and Valency States in Nanocrystalline Cerium Oxide
,”
Appl. Phys. Lett.
,
87
(
13
), pp. 133113-1–133113-3.
57.
Hailstone
,
R. K.
,
DiFrancesco
,
A. G.
,
Leong
,
J. G.
,
Allston
,
T. D.
, and
Reed
,
K. J.
,
2009
, “
A Study of Lattice Expansion in CeO2 Nanoparticles by Transmission Electron Microscopy
,”
J. Phys. Chem. C
,
113
(
34
), pp.
15155
15159
.
58.
Zhang
,
F.
,
Wang
,
P.
,
Koberstein
,
J.
,
Khalid
,
S.
, and
Chan
,
S. W.
,
2004
, “
Cerium Oxidation State in Ceria Nanoparticles Studied With X-Rray Photoelectron Spectroscopy and Absorption Near Edge Spectroscopy
,”
Surf. Sci.
,
563
(
1–3
), pp.
74
82
.
59.
Perrichon
,
V.
,
Laachir
,
A.
,
Bergeret
,
G.
,
Frety
,
R.
,
Tournayan
,
L.
, and
Touret
,
O.
,
1994
, “
Reduction of Cerias With Different Textures by Hydrogen and Their Reoxidation by Oxygen
,”
J. Chem. Soc., Faraday Trans.
,
90
(
5
), pp.
773
781
.
You do not currently have access to this content.