The resistive switching in TiO2 films studied by conductive atomic force microscopy and Kelvin probe force microscopy

Du, Yuanmin; Kumar, Amit; Pan, Hui; Zeng, Kaiyang; Wang, Xinbo; Yang, Ping; Wee, Andrew Thye Shen

doi:10.1063/1.4818119

Cited by 40 publications

(28 citation statements)

References 22 publications

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“…As indicated in the O 1s XPS spectrum, after OER reaction, there is a significant increase in the relative intensity of vacancy O 2− and O–C peaks (Figure f). The latter confirms the oxidation of carbon layer during OER, whereas the increased intensity of O 2− vacancies might have resulted from the positive voltage‐induced O 2− migration by extracting O 2− from the lattice . Therefore, we conclude that, despite the slight oxidation of the TiO x N y surface and carbon layer in the composite, its conductive and OV‐rich TiO 2− x (or Ti 2 O 3 ) outer surface was preserved during OER.…”

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confidence: 59%

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

Liu

et al. 2018

Advanced Materials

142

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The practical application of rechargeable zinc-air batteries requires a low-cost, efficient, and stable air electrode catalyst toward both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The most promising nonprecious bifunctional catalysts are carbon-supported transition metal hybrid materials. [1] However, carbon-supported catalysts suffer from carbon electrochemical oxidation, which causes the loss or aggregation of supported catalysts and degrades the electrocatalysis durability and performance. [2] To alleviate this problem, some strategies have been reported including coating the carbon support with corrosionresistive TiO 2 , [3] using conductive TiN as an alternative support, [4] or developing perovskite oxides as active catalysts. [5] However, both TiO 2 and perovskite oxides have an intrinsic low-conductivity drawback, and nor TiN is an optimum support material to obtain highly dispersed and active catalysts due to the nondefective surface structure. Thus, the objective of this study is to develop a conductive and oxidation-resistant support to relieve catalyst degradation, and at the same time achieve a high bifunctional catalytic activity with enhanced durability performance.Here, we propose that OV-rich, low-bandgap oxide semiconductor can be a promising support to design active and durable ultrafine metal catalysts in electrocatalysis (Figure 1a). This argument is built on our multidisciplinary understanding of OVs in semiconductor physics and heterogeneous solid-gas catalysis: i) the OVs lower the bandgap in oxide semiconductors: the higher the OV concentration, the higher the conductivity of the oxides [6] ; ii) in solid-gas catalysis, the OVs on oxide supports would provide a strong metal-support interaction (SMSI) with the supported metal catalysts and results in high metal dispersion, small metal size, high relative catalytic activity, and high stability. [7] That is, the OVs are not only beneficial for the conductivity of the oxides, but also offer an SMSI that favors the formation and stabilization of highly active ultrafine metal nanoparticles. Note that, in electrocatalysis, the role of OVs in metal oxides as active components is well reported for contributing to its enhanced catalytic activities. [8] However, the The highly oxidative operating conditions of rechargeable zinc-air batteries causes significant carbon-support corrosion of bifunctional oxygen electrocatalysts. Here, a new strategy for the catalyst support design focusing on oxygen vacancy (OV)-rich, low-bandgap semiconductor is proposed. The OVs promote the electrical conductivity of the oxide support, and at the same time offer a strong metal-support interaction (SMSI), which enables the catalysts to have small metal size, high catalytic activity, and high stability. The strategy is demonstrated by successfully synthesizing ultrafine Co-metaldecorated 3D ordered macroporous titanium oxynitride (3DOM-Co@TiO x N y ). The 3DOM-Co@TiO x N y catalyst exhibits comparable activities for oxygen reduction...

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confidence: 59%

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

Liu

et al. 2018

Advanced Materials

142

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“…8 Furthermore, such interface-modulated resistive switching has been extensively reported for other transition-metal oxides. [15][16][17][18][19][20][21][22] In these breakthroughs, electronic structures and physical properties of STO-based interfaces are important in the functionalization of oxide electronics. Hence, a deep understanding of charge transfer and interfacial band alignment is the key to further improve the performance of functional devices based on STO and other oxides.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the SrTiO₃–MoO₃ Interface Electronic Structure: An in Situ Photoelectron Spectroscopy Study

Peng

Mao

et al. 2015

ACS Appl. Mater. Interfaces

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Modifying the surface energetics, particularly the work function of advanced materials, is of critical importance for a wide range of surface- and interface-based devices. In this work, using in situ photoelectron spectroscopy, we investigated the evolution of electronic structure at the SrTiO3 surface during the growth of ultra-thin MoO3 layers. Because of the large work function difference between SrTiO3 and MoO3, the energy band alignment on the SrTiO3 surface is significantly modified. The charge transfer and dipole formation at the SrTiO3-MoO3 interface leads to a large modulation of work function and to apparent doping in SrTiO3. The measured evolutions of electronic structure and upward band bending suggest that the growth of ultra-thin MoO3 layers is a powerful tool with which to modulate the surface energetics of SrTiO3, and this surface engineering approach could be generalized to other functional oxides.

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“…61 Releasing oxygen gas which originated from oxygen ion oxidized at the anode results in oxygen vacancies in the ZnO film. According to the Kröger-Vink notation, this process can be expressed as…”

Section: Resultsmentioning

confidence: 99%

Metallic filament formation by aligned oxygen vacancies in ZnO-based resistive switches

2014

Journal of Applied Physics

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The resistive switching in TiO2 films studied by conductive atomic force microscopy and Kelvin probe force microscopy

Cited by 40 publications

References 22 publications

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

Evolution of the SrTiO₃–MoO₃ Interface Electronic Structure: An in Situ Photoelectron Spectroscopy Study

Metallic filament formation by aligned oxygen vacancies in ZnO-based resistive switches

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The resistive switching in TiO2 films studied by conductive atomic force microscopy and Kelvin probe force microscopy

Cited by 40 publications

References 22 publications

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

An Oxygen‐Vacancy‐Rich Semiconductor‐Supported Bifunctional Catalyst for Efficient and Stable Zinc–Air Batteries

Evolution of the SrTiO3–MoO3 Interface Electronic Structure: An in Situ Photoelectron Spectroscopy Study

Metallic filament formation by aligned oxygen vacancies in ZnO-based resistive switches

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Evolution of the SrTiO₃–MoO₃ Interface Electronic Structure: An in Situ Photoelectron Spectroscopy Study