New highly active and selective
nanostructured oxide catalysts
M. Olga Guerrero Pérez, Ricardo López-Medina
Miguel A. Bañares
Málaga, March 24th, 2008
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
What is a nanostructured catalysts?
The catalytic active phase is nanoscaled
on the surface of a support
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Nanostructured catalysts
active phase
support
bulk catalysts
supported catalysts
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Main advantages:
Industrial point of view:
Less expensive catalysts
Academic point of view:
•Support can modulate the activity
•Better insight on the nature of the active phase
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Characterization of the surface
Reactant
Reactant
Product
Product
UsuallyCatalytic
we obtain
reaction
information
Nanostructured
takesabout
placecatalysts
chemical
on the surface
structure
of catalysts
of the bulk
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Reactant
Product
Reactant
Product
Support
Structure
Coverage
Activity-selectivity
Additives
Activation / deactivation
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: Sb-V-O catalytic materials for propane
ammoxidation
NH3+O2+C3H8
CH2=CH-CN
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: VSbO4 on alumina
Sb-V-O/Al2O3
Sb+V < low coverage
not active (surface vanadia)
VOx
SbOx
Al2O3
Guerrero-Pérez et al. (2002)
Sb+V ≥ high coverage
active (VSbO4 phase)
Grasselli et col. (1992)
Guerrero-Pérez et al. (2002)
V-Sb-O
Al2O3
VSbO4 phase on alumina is not stable at low coverages
Like the bulk system, VSbO4 phase further forms during time-on-stream
hydroxypyruvic acid
mesoxalic acid
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: Uncovering reaction mechanism by operando
spectroscopy
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: Uncovering reaction mechanism by operando
spectroscopy
Dominant phase, during ammoxidation:
during reoxidation:
3+
3+
5+
Sb2O3 Sb2O4
VSbO4 + Sb2O4
VOx + VSbO4 + Sb2O3
5+ 3+
VSbO4 phases
Ammoxidation
Reoxidation
5+
O
||
V
/ | \
O O O
| | |
Al2O3
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: Uncovering reaction mechanism by operando
1Sb1V/Al
spectroscopy
8.8 ACN/V·sec
+48%
4.8 ACN/V·sec
2Sb5V/Al
Bañares et al., J.Mater.Chem.(2002)
Surface vanadia on SbVO4 species trigger
conversion/selectivity
specific rate
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 243th, 2010
Case 1: Uncovering reaction mechanism by operando
spectroscopy
Propane
5+
Sb2O4
5+ 3+
activation
VSbO4
phases
5+
O
||
V
/ | \
O O O
| | |
Al2O3
Redox cycle between surface V5+ and bulk V3+ sites
Ammoxidation
Reoxidation
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 1: Sb-V-O catalytic materials for propane
ammoxidation

VSbO4 active phase succesfully nanoscaled on the surface of alumina support.

Identified active species during propane ammoxidation by Raman spectroscopy.

Reaction Mechanism proposed.
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Mo-V-Te-Nb-O catalytic materials for propane
oxidation
useful chemical
intermediate
Acrylic acid
(fibers, polymers, resins…. and much more)
PROPYLENE
ACROLEIN
PROPANE
TWO STEP
ONE
STEPS
ACRYLIC ACID
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Mo-V-Te-Nb-O catalytic materials for propane
oxidation
Previous studies: bulk catalysts
M1 and rutile: active phases
Grasselli et al.
Guliants et al.
Ueda et al.
López Nieto et al.
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Synthesis of nanostructured catalysts
4MoVNbTe/Al2O3
12MoVNbTe/Al2O3
Bulk MoVNbTeO
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: XRD patterns of Mo-V-Te-Nb catalysts
Rutile Mo-V-Nb MoO2
Al2O3
M1
High coverage
Low coverage
0
10
20
30
40
50
2Q
60
70
80
90
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Characterization of Mo-V-Te-Nb catalysts
HRTEM confirms the presence of M1 phase
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Mo-V-Te-Nb-O catalytic materials for propane
oxidation
80
Conversion (%) or Selectivity (%)
Supported catalysts performs better!
% propane conversion
% acrylic acid
% acrolein
% propylene
% COx
60
40
20
0
MoVNbTe rutile
Bulk
4Mo5V4Nb0.5Te0.5
Low coverage
12Mo5V4Nb0.5Te0.5
High coverage
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Mo-V-Te-Nb-O catalytic materials for propane
oxidation
Nanoscaled Rutile and M1 active phases have been
succesfully supported on the surface of alumina.
It is possible to obtain active and selective
nanoscaled catalysts, that performs, even better, that
the corresponding bulk catalysts.
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Mo-V-Nb-Te-O for propane oxidation
Sb-V-O for propane ammoxidation
Rutile and M1
active phases
It have been possible to obtain active and selective
nanoscaled catalysts.
 Identification of active phase under reaction conditions.
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Catalytic Spectroscopy Laboratory
Instituto de Catálisis y Petroleoquímica, CSIC
http://www.icp.csic.es/csl
Ricardo López-Medina
Miguel A. Bañares
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Acknowledgements
Spanish Ministry of Education and
Science (CTQ2008-02461/PPQ)
MAEC-AECID Predoctoral fellowship
(RLM)
ESF (COST Action D36-006-06)
http://www.uma.es/D36
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Thank you very much for your
attention!!!
Nanospain Conference – M. Olga Guerrero Pérez
Málaga, March 24th, 2010
Case 2: Raman spectra of Mo-V-Te-Nb catalysts
VOx
MoOx
dispersed on alumina
rutile
Mo-V-O
M1
High coverage
Low coverage
MoO2 visible at low coverages
1100
900
700
500
300
100