Nanostructured Oxides in Chemistry:  Characterization and Properties

Fernández-García, Marcos; Martı́nez-Arias, A.; Hanson, Jonathan C.; Ja, Rodriguez

doi:10.1021/cr030032f

Cited by 948 publications

(627 citation statements)

References 528 publications

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“…The improved electrocatalytic response toward cyanide oxidation of the GC/Co 3 O 4 ͑XT͒ electrode is probably a consequence of the higher active area of the nanostructured spinel obtained by the xerogel template method. Nevertheless, a size-induced increase of highly reactive corner or edge surface sites compared to plane sites and electronic effects derived from changes in the bandgap width and/or the occurrence of midgap electronic states above the valence band 38 should not be ruled out as additional factors.…”

Section: ͓6͔mentioning

confidence: 99%

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Berenguer

Valdés-Solı́s

Fuertes

et al. 2008

J. Electrochem. Soc.

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Nanostructured cobalt oxide ͑Co 3 O 4 ͒ electrodes were prepared by two different methods. The first one involved the synthesis of Co 3 O 4 nanoparticles through a nanocasting route using commercial silica gel as a sacrificial template, and in the second one, the Co 3 O 4 electrodes were prepared by thermal decomposition. The electrodes were characterized by different techniques, such as scanning electron microscopy, energy-dispersive X-ray analysis ͑EDX͒, X-ray diffraction ͑XRD͒, transmission electron microscopy, X-ray photoelectron spectroscopy ͑XPS͒, and cyclic voltammetry. EDX, XRD, and XPS show a characteristic spinel-type structure and a similar chemical composition for the two nanostructured cobalt oxides. However, the surface morphology is different. The electrochemical oxidation of cyanide and phenol in alkaline medium were used as test reactions. The electrocatalytic activity of the nanocrystalline Co 3 O 4 electrodes for cyanide and phenol oxidation turned out to be highly dependent on the electrode preparation method. Conductive transition-metal oxides ͑TMOs͒ form important and diverse materials that have attracted much attention in many fields of technological interest because of their outstanding electronic, optical, magnetic, and catalytic properties.1,2 Tetragonal rutilelike TMOs containing noble-metal cations have been successfully applied as anode coatings ͓commonly known as dimensionally stable anodes ͑DSAs͔͒ in a number of important electrolytic processes, such as oxygen and chlorine evolution and the electrochemical oxidation of biorefractory organic pollutants in wastewaters.3-9 However, spinel-type cobalt oxide-based coatings have emerged as a cheaper alternative to DSA electrodes in alkaline media because they possess long-term stability under anodic conditions, good electrical conductivity, and high electrocatalytic activity toward several reactions. 2,3,[10][11][12][13][14][15][16] In addition, these materials have found use in a host of solid-state applications, such as magnetic materials, electrochromic devices, Li-ion rechargeable batteries, etc. 17-21A substantial amount of information is now available on the crystallography, structural chemistry, thermal reactivity, and surface properties of both the precursors and thermally decomposed oxide materials. However, much less attention has been paid to the morphological-and size-controlled synthesis of nanoparticles, although it has been well documented that different electrical, optical, magnetic, and mechanical properties could be reached by reducing particle dimensions to the size of 1-100 nm. [22][23][24] In spite of the lesser attention, cobalt oxide nanoparticles have been prepared by sol-gel, 18,25 reduction/oxidation route, 26 homogeneous precipitation, 27 metallorganic chemical vapor deposition, 28,29 and nanocasting approaches. 30,31 It is well known that the behavior of nanophase materials strongly depends on the shapes and sizes of the particles, which are thus a key factor in their ultimate performance and applications.Diff...

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Section: ͓6͔mentioning

confidence: 99%

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Berenguer

Valdés-Solı́s

Fuertes

et al. 2008

J. Electrochem. Soc.

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“…1 ZnO nanoparticles, with a wide band gap has found to be an efficient candidate for utilization in optical devices operating at room temperature, because of their catalytic/photocatalytic activity and use as CO gas sensor. Furthermore, ZnO is a material with excellent chemical, thermochemical and mechanical stability, which can be used to absorb ultraviolet light, protecting us against this hazardous radiation.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of brush-like ZnO nanorods using albumen as biotemplate

Nouroozi¹,

Farzaneh²

2011

J. Braz. Chem. Soc.

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Nanobastões de ZnO com morfologia similar à de escovas, estrutura cristalina do tipo wurtzita (hexagonal), diâmetro médio de 90 nm e comprimento ≥1 μm, foram preparados por calcinação (700 ° C) do material híbrido (Zn(II)/albumina) obtido pelo método sol-gel reagindo-se acetato de zinco e clara de ovo, em meio aquoso. O material foi caracterizado por difratometria de raio-X de pó (XRD), microscopia eletrônica de varredura (MEV) e de transmissão (TEM), análise termogravimétrica (TGA/DTA), e espectroscopia FT-IR e de fotoluminescência (PL). A área superficial foi determinada como sendo igual a 6,91 m 2 g -1 pelo método BET. Os eventos térmicos no TGA/DTA foram consistentes com a decomposição da albumina a 300 °C e a formação final de ZnO em 578,5 °C. Os resultados mostraram que a albumina desempenha papel essencial na formação dos nanobastões de ZnO, atuando como molde.Crystalline ZnO nanorods with wurtzite-like structure and average diameter of 90 nm and length ≥1 μm, was prepared by calcination (700 °C) of a Zn(II)/albumen hybrid obtained by solgel method, by the reaction of Zn(II) acetate and egg white (albumen), in aqueous solution. The material was characterized by powder X-ray diffraction (XRD), scanning electron (SEM) and transmission electron microscopy (TEM), thermogravimetric analysis (TGA/DTA), N 2 adsorption/ desorption (BET method), FT-IR and photoluminescence (PL) spectroscopy. The surface area was determined to be 6.91 m 2 g -1 by BET method. The TGA/DTA thermal events were consistent with the decomposition of albumen at 300 °C and final formation of ZnO at 578.5 °C. The results showed that albumen act as template playing essential role on defining the formation of ZnO nanorods with brush-like morphology.Keywords: brush-like ZnO nanorods, sol-gel method, egg white (albumen) IntroductionIn recent years, there have been many reports on novel preparation and characterization methods of nanomaterials, based on metal oxide semiconductors in general and ZnO in particular, owing to their special properties. 1 ZnO nanoparticles, with a wide band gap has found to be an efficient candidate for utilization in optical devices operating at room temperature, because of their catalytic/photocatalytic activity and use as CO gas sensor. Furthermore, ZnO is a material with excellent chemical, thermochemical and mechanical stability, which can be used to absorb ultraviolet light, protecting us against this hazardous radiation. 2 Nanostructured ZnO with as different shapes as one dimensional (1D) nanowires, 3-7 nanotubes, 8,9 nanorods 10 and nanobelts, 11 two dimensional (2D) nanostructures such as nanosheets 12 and nanowalls 13 and some three dimensional (3D) nano/microstructures such as nanoflower and tetrapod like structures, [14][15][16][17] have been fabricated by means of various methods. Thus, the fabrication methods of ZnO nanomaterials can be classified into two categories: (i) vapor phase processes and (ii) solution phase routes. [18][19][20][21][22][23] Recently, solution phase routes including microemuls...

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“…For a vast number of oxide compounds, this comes out from the fact that the preparation procedures are not able to give a size distribution approaching the delta function (39 (11), and ceria based materials, useful as DeSOx catalysts (14,15).…”

Section: Chemistry Of So 2 and Desox Processes On Oxide Nanoparticlesmentioning

confidence: 99%

“…The breakthrough number is defined as the number of 1-mL injections that are made to the reaction cell until the first trace of excess SO 2 is eluted from the bed of the adsorbent. In Table 1 From the XRD data of the nanoparticles, one can get a strain parameter that is a measurement of the lattice stress existing in the materials because of surface defects (differences in local symmetry and distances with respect to the bulk) and/or the crystal imperfections (O vacancies, other point defects, line defects and plane defects) (36,37,39). The top panel in Figure 8 shows adsorbed on the nanoparticles is somewhat more stable than that present on the (111) surfaces.…”

Section: Interaction With Al 2 O 3 and Al 2 O 3 /Mgomentioning

confidence: 99%

Chemistry of SO ₂ and DeSO _x Processes on Oxide Nanoparticles

Rodríguez¹

2006

Synthesis, Properties, and Applications of Oxide Nanomaterials

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Nanostructured Oxides in Chemistry: Characterization and Properties

Cited by 948 publications

References 528 publications

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Synthesis and characterization of brush-like ZnO nanorods using albumen as biotemplate

Chemistry of SO ₂ and DeSO _x Processes on Oxide Nanoparticles

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Nanostructured Oxides in Chemistry: Characterization and Properties

Cited by 948 publications

References 528 publications

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods

Synthesis and characterization of brush-like ZnO nanorods using albumen as biotemplate

Chemistry of SO 2 and DeSO x Processes on Oxide Nanoparticles

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Chemistry of SO ₂ and DeSO _x Processes on Oxide Nanoparticles