TY - JOUR
T1 - Preparation of platinum-iridium nanoparticles on titania nanotubes by MOCVD and their catalytic evaluation
AU - Colindres, S. Capula
AU - García, J. R.Vargas
AU - Antonio, J. A.Toledo
AU - Chavez, C. Angeles
N1 - Funding Information:
This work was supported by the National Polytechnic Institute of Mexico (IPN) and Petroleum Mexican Institute (IMP) through the projects IPN-SIP 20070781 and D.00237.
PY - 2009/8/26
Y1 - 2009/8/26
N2 - Pt based catalysts are commonly used in several industrial processes involving hydrogenation and dehydrogenation reactions. New deposition methods as well as support materials are being investigated to generate new catalysts with superior catalytic activity. In this work, platinum-iridium (Pt-Ir) nanoparticles of about 5 nm in size were supported on titania (TiO2) nanotubes by metal organic chemical vapor deposition (MOCVD). The TiO2 nanotubes were prepared by an alkali hydrothermal method using sodium hydroxide solution at 100 °C, during 64.8 ks. Pt-Ir nanoparticles were obtained by controlling the MOCVD conditions at 400 °C and 66.6 kPa. Textural properties and particle size were investigated by nitrogen physisorption (BET method), X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. Catalytic activity was measured in cyclohexene disproportion as the test molecule for hydrogenation/dehydrogenation reactions. The TiO2 nanotubes exhibit a considerable high surface area of about 425,000 m2/kg, however, after calcination at 400 °C their nanotubular morphology was partially transformed. In spite of this change, the 5 nm Pt-Ir nanoparticles supported on TiO2 nanotubes were more active in the cyclohexene disproportion reaction than conventional Pt-Ir/alumina catalysts in the whole range of temperatures investigated (50-250 °C). Hydrogenation reactions (high selectivity to cyclohexane) predominate at temperatures below 150 °C.
AB - Pt based catalysts are commonly used in several industrial processes involving hydrogenation and dehydrogenation reactions. New deposition methods as well as support materials are being investigated to generate new catalysts with superior catalytic activity. In this work, platinum-iridium (Pt-Ir) nanoparticles of about 5 nm in size were supported on titania (TiO2) nanotubes by metal organic chemical vapor deposition (MOCVD). The TiO2 nanotubes were prepared by an alkali hydrothermal method using sodium hydroxide solution at 100 °C, during 64.8 ks. Pt-Ir nanoparticles were obtained by controlling the MOCVD conditions at 400 °C and 66.6 kPa. Textural properties and particle size were investigated by nitrogen physisorption (BET method), X-ray diffraction, Raman spectroscopy and high resolution transmission electron microscopy. Catalytic activity was measured in cyclohexene disproportion as the test molecule for hydrogenation/dehydrogenation reactions. The TiO2 nanotubes exhibit a considerable high surface area of about 425,000 m2/kg, however, after calcination at 400 °C their nanotubular morphology was partially transformed. In spite of this change, the 5 nm Pt-Ir nanoparticles supported on TiO2 nanotubes were more active in the cyclohexene disproportion reaction than conventional Pt-Ir/alumina catalysts in the whole range of temperatures investigated (50-250 °C). Hydrogenation reactions (high selectivity to cyclohexane) predominate at temperatures below 150 °C.
KW - Catalysis
KW - Nanostructured materials
KW - Vapor deposition
UR - http://www.scopus.com/inward/record.url?scp=69249230929&partnerID=8YFLogxK
U2 - 10.1016/j.jallcom.2008.08.097
DO - 10.1016/j.jallcom.2008.08.097
M3 - Artículo
SN - 0925-8388
VL - 483
SP - 406
EP - 409
JO - Journal of Alloys and Compounds
JF - Journal of Alloys and Compounds
IS - 1-2
ER -