Universidad Nacional Autónoma de México - CNyN

1st International Symposium on Nanoscience and Nanomaterials
a vcorral@ciqa.mx, b cevalmart_18@hotmail.com, c mgarciaguaderrama@dip.udg.mx,
d enrique.torres@cimav.edu.mx
Keywords: Chemical Growth, Nanomaterials, Zinc Oxide.
Zinc oxide rods were synthesized by aqueous chemical growth on different substrates, e.g. plane
glass, ITO-coated glass substrates, stainless steel and platinum-coated silicon wafers. The effect of pressure
was studied on open and closed reaction vessels at 90ºC for six hours on ITO-coated glass substrates. Closed
reaction gave rise to conic shaped rods with average diameter of 0.61 ± 0.21 µm, while more homogeneous
rods of 0.91 ± 0.17 µm were grown at open conditions. Rod length increased from 3.00 ± 0.47 to 3.67 ± 0.92
for close and open conditions respectively. As for the effect of reaction time, a sample was grown for 20
hours at closed conditions. Ave. diameter was not affected significantly, while length increased up to 7.30 ±
0.85 µm. Pt-coated silicon and stainless steel substrates promoted the formation of ZnO rods with a flowerlike
morphology, with similar dimensions than those grown over glass. In all cases, the hexagonal phase was
verified by grazing incidence X- ray diffraction.
O-021
Au/Ce-Al-O CATALYSTS FOR AEROBIC OXIDATIVE ESTERIFICATION OF BENZYL
ALCOHOL
E. Smolentseva 1,a , A. Simakov 1,b , R. Cotta 2,c , V. Costa 2,d , E. Gusevskaya 2,e , S. Fuentes 1,f
1 Universidad Nacional Autónoma de México, Centro de Nanociencia y Nanotecnología, km.107, carr. Tijuana
- Ensenada, C.P. 22860, Ensenada, B.C., México.
2 Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
a elena@cnyn.unam.mx, b andrey@cnyn.unam.mx, c, d, e elena@ufmg.br, f fuentes@cnyn.unam.mx
Keywords: Ce-Al mixed oxides, gold nanoparticles, benzyl alcohol, aerobic oxidation.
Gold nanoparticles (NPs) are considered as the promising catalysts for the aerobic oxidation of
alcohols, which involve O 2 as an oxidant, due to their high activity and stability. Gold catalysts (3 wt.% Au)
supported on single and mixed nanostructured oxides (Al 2 O 3 , CeO 2 and Ce-Al-O) were prepared by
deposition-precipitation with urea and studied in aerobic oxidative esterification of benzyl alcohol in the
presence of methanol. Fresh and spent samples were characterized by FTIR, in situ UV-Visible spectroscopy
and TEM. It was found that the gold catalysts supported on ceria and Ce-Al-O mixed oxides are quite
effective for the liquid-phase oxidation of benzyl alcohol with formation of two products: aldehyde and ester,
even in the absence of base promoter. The selectivity of catalysts depends on the nature of the support used,
the type of catalysts pretreatment (reductive or oxidative), temperature and the reaction time. The authors
thank to E. Flores, P. Casillas, V. García, F. Ruiz, E. Aparicio, M. Vega, J. Palomares, M. Sainz and J. Peralta
for their kind technical support in this work. This project was supported by DGAPA–PAPIIT (UNAM,
Mexico) through grant 224510.
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