-Fe2O3 2 conversion
1
Aryane A. Marciniak 1* ; Evelyn C.S.Santos 2 ; Odivaldo C. Alves 3 ; Flávio Garcia 2 ; Claudio J. A. Mota 1 . 1 Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; 2 Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brasil; 3 Universidade Federal Fluminense, Niterói, Brasil. *ary [email protected] Methodologies Conclusion Acknowledgements Introduction • α-Fe 2 O 3 nanorings were prepared using a microwave-driven method, which is more sustainable than the conventional method, reducing time and energy; • The CeFe-11 catalyst presented the best performance (7.2 mmol DMC /g cat ) in converting CO 2 to organic carbonate (DMC). This result may be associated with its high surface area (95 m 2 /g) and the presence of oxygen vacancies. ✓ Hematite (α-Fe 2 O 3 ) is abundant in nature and can present several morphologies, depending on the preparation method; ✓ The conventional hydrothermal procedure is the most used to prepared nanoring-shaped hematite. However, with prolonged reaction time (48 h); ✓ Microwave-driven (MW) methods have been used to reduce time and energy in different processes; ✓ α-Fe 2 O 3 presents interesting properties for catalysis applications and can be doped or impregnated with CeO 2; ✓ The conversion of CO 2 , a greenhouse gas, to valuable products is an important and sustainable process; ✓ In this work, we show the potential synergistic effect between CeO 2 and α-Fe 2 O 3 nanorings (NR) as a green and sustainable catalysts in the CO 2 conversion into DMC. Microwave-driven hydrothermal synthesis of α-Fe 2 O 3 nanorings as CeO 2 catalyst support for CO 2 conversion 20 30 40 50 60 70 80 90 −Fe 2 O 3 CeFe-21 CeFe-15 CeFe-12 * * * * * * * * −Fe 2 O 3 CeFe-11 CeO 2 Intensity (a.u.) 2 (degree) * * CeO 2 Results and discussion Powder XRD patterns: two crystalline phases, hematite (PDF 33-0664) and CeO 2 (JCPDS 34- 0394). SEM: α-Fe 2 O 3 presented highly ordered nanorings, mostly with edge lengths between 100 and 110 nm. TEM image of CeFe-11 shows the presence of α-Fe 2 O 3 nanorings well decorated with CeO 2 nanoparticles. CeO 2 + CeO 2 1:0 1:0.5 1:1 1:2 1:5 0:1 1 2 3 4 5 6 7 8 DMC (mmol/g cat ) Ce:Fe Molar ratio 20 30 40 50 60 70 80 90 100 Surface area (m 2 /g) Catalytic performance MeOH 15 mL 140°C/3 h The product was analyzed by GC- MS + 100 mg Cat. Catalyst was separated by centrifugation 50 bar CO 2 0 2000 4000 6000 CeFe-21 CeFe-15 CeFe-12 CeFe-11 Intensity (a.u.) Magnetic field (G) −Fe 2 O 3 Ce 3+ (g= 1.96) EPR was used to evaluate the presence of oxygen vacancies (Ov) in the lattice; the α-Fe 2 O 3 did not present Ov signals; the Ov signal decreases according to the Ce:Fe molar ratio. Ov (g= 2.02) ➢ All α-Fe 2 O 3 nanoring catalysts impregnated with CeO 2 showed higher DMC yield compared to pure CeO 2 (1.5 mmol DMC /g cat ) and α-Fe 2 O 3 (1.6 mmol DMC /g cat ); ➢ The results may be associated with the higher surface area, which seems to be essential in the synthesis of DMC; ➢ The CeFe-11 presented the best catalytic activity for CO 2 conversion to DMC.
Transcript of -Fe2O3 2 conversion
Aryane A. Marciniak1*; Evelyn C.S.Santos2; Odivaldo C. Alves3; Flávio Garcia2; Claudio J. A. Mota1.
1Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brasil; 2Centro Brasileiro de Pesquisas Físicas, Rio de Janeiro, Brasil;3Universidade Federal Fluminense, Niterói, Brasil. *[email protected]
Methodologies
ConclusionAcknowledgements
Introduction
• α-Fe2O3 nanorings were prepared using a microwave-driven method, which is
more sustainable than the conventional method, reducing time and energy;
• The CeFe-11 catalyst presented the best performance (7.2 mmolDMC/gcat) in
converting CO2 to organic carbonate (DMC). This result may be associated with
its high surface area (95 m2/g) and the presence of oxygen vacancies.
✓ Hematite (α-Fe2O3) is abundant in nature and can present several
morphologies, depending on the preparation method;
✓ The conventional hydrothermal procedure is the most used to prepared
nanoring-shaped hematite. However, with prolonged reaction time (48 h);
✓ Microwave-driven (MW) methods have been used to reduce time and
energy in different processes;
✓ α-Fe2O3 presents interesting properties for catalysis applications and can
be doped or impregnated with CeO2;
✓ The conversion of CO2, a greenhouse gas, to valuable products is an
important and sustainable process;
✓ In this work, we show the potential synergistic effect between CeO2 and
α-Fe2O3 nanorings (NR) as a green and sustainable catalysts in the CO2
conversion into DMC.
Microwave-driven hydrothermal synthesis of α-Fe2O3
nanorings as CeO2 catalyst support for CO2 conversion
20 30 40 50 60 70 80 90
−Fe2O
3
CeFe-21
CeFe-15
CeFe-12
* * ******
−Fe2O
3
CeFe-11
CeO2
Inte
nsi
ty (
a.u
.)
2 (degree)
*
* CeO2
Results and discussion
Powder XRD patterns: two crystalline phases,
hematite (PDF 33-0664) and CeO2 (JCPDS 34-
0394).
SEM: α-Fe2O3 presented
highly ordered nanorings,
mostly with edge lengths
between 100 and 110 nm.
TEM image of CeFe-11 shows the
presence of α-Fe2O3 nanorings well
decorated with CeO2 nanoparticles.
CeO2
+ CeO2
1:0 1:0.5 1:1 1:2 1:5 0:11
2
3
4
5
6
7
8
DM
C (
mm
ol/g
cat)
Ce:Fe Molar ratio
20
30
40
50
60
70
80
90
100
Su
rface a
rea (
m2/g
)
Catalytic performance
MeOH
15 mL
140°C/3 h
The product was
analyzed by GC-
MS
+
100 mg
Cat.
Catalyst was
separated by
centrifugation
50 bar
CO2
0 2000 4000 6000
CeFe-21
CeFe-15
CeFe-12
CeFe-11
Inte
ns
ity
(a
.u.)
Magnetic field (G)
−Fe2O
3
Ce3+(g= 1.96)
EPR was used to evaluate the presence of
oxygen vacancies (Ov) in the lattice; the α-Fe2O3
did not present Ov signals; the Ov signal
decreases according to the Ce:Fe molar ratio.
Ov (g= 2.02)
➢ All α-Fe2O3 nanoring catalysts impregnated with CeO2 showed higher DMC yield
compared to pure CeO2 (1.5 mmolDMC/gcat) and α-Fe2O3 (1.6 mmolDMC/gcat);
➢ The results may be associated with the higher surface area, which seems to be
essential in the synthesis of DMC;
➢ The CeFe-11 presented the best catalytic activity for CO2 conversion to DMC.
