Formation of Highly Ordered Nanochannel Nb Oxide by Self‐Organizing Anodization

Lee, Ki-Young; Yang, Yang; Yang, Min; Schmuki, Patrik

doi:10.1002/chem.201201426

Cited by 37 publications

(35 citation statements)

References 73 publications

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“…16,17 Another electrochermical approach was pionired by Surganov and Mozalev,18 in which one-dimensional (1-D) spatially-ordered metal-oxide nanostructures are synthesized via anodizing a thin layer of Al superimposed on a layer of different valve metal. In 5 this approach, a nanoporous alumina is first formed from the Al layer, this being followed by processing the underlying metal through the alumina nanopores.…”

Section: Introductionmentioning

confidence: 99%

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

et al. 2014

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Nanostructured niobium oxide (NO) semiconductor is gaining increasing attention as electronic, optical, and electro-optic material. However, the preparation of stable NO nanofilms with reproducible morphology and behavior remains a challenge. 10Here we show a rapid, well-controlled, and efficient way to synthesize NO films with the self-organized columnlike nanostructured morphologies and advanced functional properties. The films are developed via the growth of a nanoporous anodic alumina layer, followed by the pore-directed 15 anodizing of the Nb underlayer. The columns may grow 30-150 nm wide, up to 900 nm long, with the aspect ratio up to 20, being anchored to a thin continuous oxide layer that separates the columns from the substrate. The as anodized films have a graded chemical composition changing from amorphous Nb 2 O 5 mixed with Al 2 O 3 , Si-, and P-containing species in the surface region to NbO 2 in the lower film layer. The post-anodizing treatments result in the controlled 20 formation of Nb 2 O 5 , NbO 2 , and NbO crystal phases, accompanied by transformation from nearly perfect dielectric to n-type semiconductor behavior of the films. The approach allows for the smooth film growth without early dielectric breakdown, stress-generated defects, or destructive dissolution at the respective interfaces, which is a unique situation in the oxide films on niobium. The functional properties of the NO films, revealed to date, allow for potential applications as nanocomposite capacitor dielectrics and active 25 layers for semiconductor gas microsensors with the sensitivity to ethanol and the response to hydrogen being among best ever reported.

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Section: Introductionmentioning

confidence: 99%

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

et al. 2014

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“…[1][2][3] Anodization is an attractive method for fabricating oxides, including those of niobium, because of the possibility of creating self-organized structures with a high degree of order. While far less studied than aluminum, anodization of niobium has been reported to result in structures ranging from random porous films [4] and sunflower formations [5] to granular forms [6] and membranes with smooth, linear pores [7] or with rough, vein-like pores. [8] A particularly intriguing morphology is that of microcones, which appears to be unique to anodized niobium.…”

Section: Introductionmentioning

confidence: 99%

Rapid and controlled electrochemical synthesis of crystalline niobium oxide microcones

et al. 2015

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We demonstrate the fabrication by anodization of niobium oxide microcones, several microns long, from aqueous solutions of 1 wt% hydrogen fluoride (HF) with varied sodium fluoride (NaF) concentration (0-1 M). Raman spectroscopy and x-ray diffractometer analysis revealed the as-grown microcones to be crystalline Nb 2 O 5−x with preferred (1 0 0) and (0 1 0) orientations. The overall Nb 2 O 5−x formation rate increased with the increasing NaF concentration, and structures as tall as 20 μm were achieved in just 20 min of anodization at 1 M NaF. Rapid formation of niobia microcones was even observed in the absence of HF at this NaF concentration. Photocatalytic activity for water oxidation was highest for microcones grown under the highest NaF concentration.

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“…Nióbio surge como uma excelente alternativa como fotocatalisador, pois ele tem uma banda de energia adequada (3,4 eV) para fotólise da água. O Brasil possui as reservas de nióbio mais abundantes do mundo [4], e isso se torna mais um atrativo para o estudo desse material, além disso, há vários relatos de obtenção de óxidos de nióbio por anodização [5][6]. Para aumentar a eficiência da atividade fotocatalítica, e melhorar a produção de hidrogênio, são utilizados reagentes de sacrifício, por exemplo, metanol, etanol e etilamina [7].…”

Section: Introductionunclassified

Preparação E Caracterização De Fotocatalisadores De Óxido De Nióbio Aplicados Na Produção De Hidrogênio Utilizando Glicerol Como Agente De Sacrifício

Proença¹,

Correa²,

Rodrigues³

et al. 2017

Anais Do Enemet - Encontro Nacional De Estudantes De Engenharia Metalúrgica, De Materiais E De Minas

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ResumoFotocatalisadores de nióbio foram obtidos por anodização a 15 V, utilizando uma solução de K2HPO4 10% p/p em glicerol anidro como eletrólito por 15 minutos. As amostras foram caracterizadas por difração de raios-X para avaliação da estrutura cristalina obtida. A fotodegradação do glicerol (utilizado como agente de sacrifício) foi avaliada pela técnica de cromatografia líquida de alta eficiência. Palavras-chave: Nióbio; Hidrogênio; Fotocatálise; Anodização. PREPARATION AND CHARACTERIZATION OF NIOBIUM OXIDE APPLIED IN PHOTOGENERATION H2 USING GLYCERL AS SACRIFICE AGENT AbstractPhotocatalysts of niobium were obtained by anodization process at 15 V by using a solution of K2HPO4 10% w/w anhydrous glycerol as the electrolyte for 15 minutes. The samples were characterized by X-ray diffraction to evaluate the crystal structure obtained. The photodegradation of glycerol (used as a sacrificial agent) was assessed by liquid chromatography of high efficiency.

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Formation of Highly Ordered Nanochannel Nb Oxide by Self‐Organizing Anodization

Cited by 37 publications

References 73 publications

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

Formation–structure–properties of niobium-oxide nanocolumn arrays via self-organized anodization of sputter-deposited aluminum-on-niobium layers

Rapid and controlled electrochemical synthesis of crystalline niobium oxide microcones

Preparação E Caracterização De Fotocatalisadores De Óxido De Nióbio Aplicados Na Produção De Hidrogênio Utilizando Glicerol Como Agente De Sacrifício

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