Mechanisms of Reactions in the Solid State: (110) Al<sub>2</sub>O<sub>3</sub> + (001) ZnO Interfacial Reaction

Pin, Sonia; Newton, Mark A.; d’Acapito, Francesco; Zema, Michele; Tarantino, Serena C.; Spinolo, G.; Souza, Roger A. De; Martin, Manfred; Ghigna, Paolo

doi:10.1021/jp209622u

Cited by 8 publications

(22 citation statements)

References 23 publications

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“…This is in a sense the true chemical reaction and has been much less investigated with respect to the other reaction regimes (Kotula & Carter, 1995). Concerning the last topic, we have recently shown (Ghigna et al, 2003(Ghigna et al, , 2010d'Acapito et al, 2003a,b;Pin et al, 2009Pin et al, , 2011Pin et al, , 2013a the effectiveness of an approach to the chemical reactivity in the solid state based on the use of model reacting systems (NiO + Al 2 O 3 and particularly ZnO + Al 2 O 3 ) made of a thin layer of one reagent deposited onto a singlecrystal slab of the other reagent. The system is investigated by combining several experimental techniques and comparing the results obtained starting from different film-to-crystal orientations and different film thicknesses.…”

Section: Introductionmentioning

confidence: 96%

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)

et al. 2014

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The reaction between NiO and (0001)- and (1102)-oriented Al2O3 single crystals has been investigated on model experimental systems by using the ReflEXAFS technique. Depth-sensitive information is obtained by collecting data above and below the critical angle for total reflection. A systematic protocol for data analysis, based on the recently developed CARD code, was implemented, and a detailed description of the reactive systems was obtained. In particular, for (1102)-oriented Al2O3, the reaction with NiO is almost complete after heating for 6 h at 1273 K, and an almost uniform layer of spinel is found below a mixed (NiO + spinel) layer at the very upmost part of the sample. In the case of the (0001)-oriented Al2O3, for the same temperature and heating time, the reaction shows a lower advancement degree and a residual fraction of at least 30% NiO is detected in the ReflEXAFS spectra.

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Section: Introductionmentioning

confidence: 96%

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)

et al. 2014

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“…We postulate that the NWalls also form a ZnAl 2 O 4 /Al 2 O 3 interface but is only present on the shell surface of the NWalls (40 Å) [25]. Recent theoretical studies have been done to show that Al 2 O 3 and ZnO interfacial reaction eventually leads to a spinel ZnAl 2 O 4 [26,27].…”

Section: Discussion On the Growth Mechanismmentioning

confidence: 93%

Sonochemical approach for rapid growth of zinc oxide nanowalls

et al. 2012

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The sonochemical process drives chemical reactions with sound fields by creating extraordinarily high density of energy, pressure and temperatures. The process resulted in a number of unexpected chemical species and thought-provoking results in the recent past. In this paper, we present a new sonochemical approach to synthesize ZnO (zinc oxide) nanowalls (NWalls) on aluminum and alumina coated substrates at room ambient conditions. We achieved highly dense and uniform ZnO NWalls in areas that are coated with Al or Al 2 O 3 (alumina). The synthesis process was shown not to occur on Si, SiO 2 , Cr, or Ag surfaces. A series of experiments on understanding the growth kinetics offers detailed insight into the growth dynamics over time. Photoluminescence (PL) measurements, UV Vis spectroscopy, and SEM-EDS results confirm NWalls composed of crystalline ZnO that are formed via Al assisted growth induced by phase transformations under extraordinary pressure, temperature, and chemical growth kinetics. The chemical growth method as reported here, is applicable to arbitrary A.P. Nayak · A.M. Katzenmeyer · M.S. Islam ( ) substrates coated with an Al thin film. We demonstrate the applications of the as-formed NWalls in UV photoconductors and gas sensors.

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“…For the sake of clarity, all the spectra are here displayed shifted along the y -axis. Upon increase in the annealing temperature the XANES manifold at the Zn–K edge undergoes a well-evident change from an almost structureless shape to a ZnO-like structure. − Since XANES spectroscopy can be used for fingerprinting crystallographic phases, this is a clear indication that the thermal treatments cause the polymeric precursor to yield a wurtzite-type ZnO phase. This process is apparently concluded after 550 °C.…”

Section: Resultsmentioning

confidence: 99%

Mechanisms of Zinc Oxide Nanocrystalline Thin Film Formation by Thermal Degradation of Metal-Loaded Hydrogels

Tredici

Resmini

et al. 2013

J. Phys. Chem. C

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Thermal degradation of metal-loaded hydrogel films is a powerful tool to synthesize high-quality metal oxide thin films with nanometric grain size, but the formation mechanism is still poorly known. We exploited fluorescence X-ray absorption fine structure as a short-range probe to investigate the first stages of nucleation and the following development of ZnO nanoparticles in Zn-loaded hydrogels, annealed for 20 min at temperatures between 150 and 500 °C. The experimental results evidenced that the first nuclei of ZnO begin to form at 300 °C, whereas at 350 °C the ZnO nanoparticles are already well crystallized. By coupling the results with those obtained by thermal analysis, profilometry, HR-TEM, diffraction and μ-FTIR, a formation mechanism was suggested. The optical and electrical properties of the samples confirm that the polymer forms an insulating shell around the nanoparticles up to 450 °C: the intimate hybridization promotes stress relaxation during the annealing, yielding crack-free metal oxide films. Prolongation of the annealing time allowed the removal of the organic shell at 350 °C, yielding fully conductive, transparent ZnO films with particle size reduced to 7 nm.

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Mechanisms of Reactions in the Solid State: (110) Al₂O₃ + (001) ZnO Interfacial Reaction

Cited by 8 publications

References 23 publications

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)

Sonochemical approach for rapid growth of zinc oxide nanowalls

Mechanisms of Zinc Oxide Nanocrystalline Thin Film Formation by Thermal Degradation of Metal-Loaded Hydrogels

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Mechanisms of Reactions in the Solid State: (110) Al2O3 + (001) ZnO Interfacial Reaction

Cited by 8 publications

References 23 publications

Studying the surface reaction between NiO and Al2O3viatotal reflection EXAFS (ReflEXAFS)

Studying the surface reaction between NiO and Al2O3viatotal reflection EXAFS (ReflEXAFS)

Sonochemical approach for rapid growth of zinc oxide nanowalls

Mechanisms of Zinc Oxide Nanocrystalline Thin Film Formation by Thermal Degradation of Metal-Loaded Hydrogels

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Product

Resources

About

Mechanisms of Reactions in the Solid State: (110) Al₂O₃ + (001) ZnO Interfacial Reaction

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)

Studying the surface reaction between NiO and Al₂O₃viatotal reflection EXAFS (ReflEXAFS)