Enhanced visible light photocurrent generation at surface-modified TiO2 nanotubes

Beránek, Radim; Macák, Jan M.; Gärtner, Marc; Meyer, Karsten; Schmuki, Patrik

doi:10.1016/j.electacta.2008.10.063

Cited by 90 publications

(65 citation statements)

References 74 publications

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“…3b) are actually much more intense, compared to the N doping of anodic TiO 2 nanotubes through ion implantation or annealing method in NH 3 atmosphere, where efforts to make highly N-doped led to only limited N doping. [40][41][42] This indicates that the N interactions with the TiO 2 are quite different for the wet process, i.e., the present study, and the dry process, i.e., implantation or annealing in NH 3 atmosphere. In case of ion implantation or annealing method, N reacted with TiO 2 only on the surface or the tube walls but not bulk.…”

Section: Resultsmentioning

confidence: 88%

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

Kure‐Chu

Sakuyama

Suzuki

et al. 2018

J. Electrochem. Soc.

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We report a novel three-dimensional nanoporous TiO 2 -TiO-TiN (Np-TTT) ternary composite film with cylindrical pores of diameter φ30-50 nm and laminated tier thickness of 10-30 nm, which was fabricated straightforwardly on a Ti foil via a one-step anodization in an aqueous nitric electrolyte. The Np-TTT composite films consisted of amorphous TiO 2 matrix, quasi-crystalline TiO, and a small amount of TiN (∼2 at% as N), which are formed simultaneously during anodization through electrochemical and/or chemical reactions in the nitric electrolyte. As a binder-free and auxiliary-component-free anode material for lithium-ion batteries, the capacity and rate performance of the Np-TTT anodes were dependent on both the anodizing conditions and crystalline structure. Particularly, the Np-TTT composite film (∼800 nm-thick) that was annealed at 250 • C for 1 h exhibited the highest areal specific capacity of 440 μAh cm −2 at the 1 st cycle, a high retention of 95% from the 2 nd to the 50 th cycles, and a Coulombic efficiency of approximately 100%. The enhanced capacities of the Np-TTT composite films can be primarily attributed to the synergetic effect of the inclusion of conductive TiN component in bulk TiO 2 matrix films, the active TiO with quasi-crystalline cubic phase, and nanoporous structure with high surface area. Rechargeable lithium-ion batteries (LIBs) are considered one of the most important energy storage device and widely used in various potable electronic devices like mobile phones, cameras, and laptops, owing to their superior energy densities (120-180 W h kg -1 ), low memory effect, long life cycle, and low environmental impacts. 1-3Currently, their applications are quickly expanding to electric vehicles (EVs) and plug-in hybrid electric vehicles (HEVs), where much higher energy densities (above 500 W h kg -1 ) are necessary to supply sufficient power for long-distance driving, accelerating a vehicle quickly, and recovering energy during braking. [4][5][6] However, the safety issue of LIBs is becoming a severe problem because the conventional graphite anode (0.1 V vs. Li + /Li) is prone to experience the growth of lithium dendrites after repetitive charge/discharge, which hinders the development of large-capacity LIBs in EV and HEV applications. 4,6,7 Titanium dioxide materials have attracted increasing attention as promising LIB anode materials for replacing conventional graphite anodes owing to their superior features such as safety improvement, low cost, cycling stability, and satisfactory chemical and thermal stabilities.3,7-14 Particularly, TiO 2 exhibits very small volume expansion (<4%) and, more importantly, operates at a relatively high working voltage (1.7 V vs. Li/Li + ) during Li + insertion/extraction, which eliminates the influence of the solid electrolyte interface layer and avoids the risk of lithium electrodeposition from electrolytes in LIBs, thus further ensuring the cycling stability and safety of batteries. However, the poor Li ion diffusivity and low electronic conductivity of TiO 2 ma...

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Section: Resultsmentioning

confidence: 88%

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

Kure‐Chu

Sakuyama

Suzuki

et al. 2018

J. Electrochem. Soc.

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“…Drawing on the fundamental studies on dye sensitization of other wide bandgap semiconductors (ZnO, SnO 2 ) in the 1960s [55][56][57][58][59], attaching visiblelight-absorbing organic dyes to the surface of TiO 2 [60,61] has led to fabrication of regenerative dye-sensitized solar cells with the overall solar conversion efficiencies exceeding 10% [62][63][64]. Other sensitization approaches utilize chromophores like semiconductor quantum dots [65][66][67][68][69][70], plasmonic metal nanocrystals [71][72][73][74][75], simple coordination compounds like chloroplatinate (IV) complexes [29,32,76] or ferrocyanide ions [77][78][79], stable polymeric compounds [38,39,[80][81][82][83], or metal ions (Cu 2+ , Fe 3+ ) grafted onto the TiO 2 surface [84,85]. In contrast to these surfaceconfined sensitization protocols, bulk-doping of TiO 2 has also attracted significant interest.…”

Section: Introductionmentioning

confidence: 99%

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

Beránek

2011

Advances in Physical Chemistry

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332

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TiO 2 -based nanomaterials play currently a major role in the development of novel photochemical systems and devices. One of the key parameters determining the photoactivity of TiO 2 -based materials is the position of the band edges. Although its knowledge is an important prerequisite for understanding and optimizing the performance of photochemical systems, it has been often rather neglected in recent research, particularly in the field of heterogeneous photocatalysis. This paper provides a concise account of main methods for the determination of the position of the band edges, particularly those suitable for measurements on nanostructured materials. In the first part, a survey of key photophysical and photochemical concepts necessary for understanding the energetics at the semiconductor/solution interface is provided. This is followed by a detailed discussion of several electrochemical, photoelectrochemical, and spectroelectrochemical methods that can be applied for the determination of band edge positions in compact and nanocrystalline thin films, as well as in nanocrystalline powders.

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“…Einfacher sind thermische Behandlungen in NH 3 [306] oder eine Modifizierung durch Harnstoffpyrolyse. [307] Während die Behandlung in NH 3 tatsächlich im XPS-Spektrum zur Signatur einer Ti-NBildung bei 396 eV führt, scheint die Harnstoffbehandlung hauptsächlich zu einer Oberflächensensibilisierung durch CN=C-und CNH 2 -Gruppen zu führen. Solche oberflächen-modifizierten Nanoröhren zeigen jedoch verglichen mit nichtmodifizierten Nanoröhren eine signifikante Photoantwort im sichtbaren Bereich.…”

Section: Dotierungenunclassified

TiO₂‐Nanoröhren: Synthese und Anwendungen

2011

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TiO2 ist eine der am besten untersuchten Verbindungen in den Materialwissenschaften und weist einige herausragende Eigenschaften auf, die z. B. für die Photokatalyse, für farbstoffsensibilisierte Solarzellen oder für biomedizinische Funktionseinheiten genutzt werden. 1999 zeigten erste Berichte, dass es möglich ist, hoch geordnete Anordnungen von TiO2‐Nanoröhren durch eine einfache, aber optimierte elektrochemische Anodisierung einer Ti‐Metallfolie herzustellen. Dies löste intensive Forschungsaktivitäten aus, deren Schwerpunkt auf der Herstellung und der Modifizierung sowie auf den Eigenschaften und Anwendungen dieser eindimensionalen Nanostrukturen lagen. Dieser Aufsatz geht auf all diese Aspekte und die zugrundeliegenden Prinzipien und funktionellen Haupteigenschaften von TiO2 ein und will außerdem versuchen, Entwicklungsperspektiven für das Gebiet aufzuzeigen.

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Enhanced visible light photocurrent generation at surface-modified TiO2 nanotubes

Cited by 90 publications

References 74 publications

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

TiO₂‐Nanoröhren: Synthese und Anwendungen

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Enhanced visible light photocurrent generation at surface-modified TiO2 nanotubes

Cited by 90 publications

References 74 publications

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO2–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO2–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO2‐Based Nanomaterials

TiO2‐Nanoröhren: Synthese und Anwendungen

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Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

Tailoring of Morphology and Crystalline Structure of Nanoporous TiO₂–TiO–TiN Composite Films for Enhanced Capacity as Anode Materials of Lithium-Ion Batteries

(Photo)electrochemical Methods for the Determination of the Band Edge Positions of TiO₂‐Based Nanomaterials

TiO₂‐Nanoröhren: Synthese und Anwendungen