Hysteretic phase transformation of two-dimensional TiO2

Yang, Jing; Gao, Meizhen; Jiang, Subin; Huo, Xuejian; Xia, Rui

doi:10.1016/j.matlet.2018.08.045

Cited by 9 publications

(4 citation statements)

References 15 publications

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“…The nature of carbonaceous residues can be further identified by temperatureprogrammed reduction (TPR). Carbonaceous residues that are easily reduced are believed to help in a decoking process that leads to CO formation; this surface carbide is denominated α-C and displays reduction temperatures of between 300 and 310 • C. β-C is reduced in the range of 580 to 600 • C and is attributed to amorphous carbon, which contributes to deactivation mechanisms [27]. Any carbonaceous residue that is reducible at higher temperatures is attributed to very stable graphitized carbon that participates in deactivation mechanisms and is classified as γ-C [28,29].…”

Section: Resultsmentioning

confidence: 99%

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

et al. 2021

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In this paper, nanowire-supported catalysts loaded with nickel are shown to be coke resistant compared to nanoparticle-supported catalysts. Specifically, Ni-loaded titania-based nanowire catalysts were tested with the dry methane reforming process in a laboratory-scale continuous packed-bed atmospheric reactor. The CO2 conversion rate stayed above 90% for over 30 h on stream under coke-promoting conditions, such as high flow rates, low temperatures, and a high ratio of CH4 to CO2. The coke (CxHy, x>>y) on the spent catalyst surface for both nanowire- and nanoparticle-supported catalysts was characterized by TGA, temperature-programmed reduction (TPR), and electron microscopy (SEM/TEM/EDS), and it was revealed that the types of carbon species present and their distribution over the morphology-enhanced materials played a major role in the deactivation. The CO2 conversion activity of Ni supported on titania nanoparticles was reduced from ~80% to less than 72% in 30 h due to the formation of a graphitic coke formation. On the other hand, Ni particles supported on nanowires exhibited cube-octahedral morphologies, with a high density of non- (111) surface sites responsible for the increased activity and reduced graphitic coke deposition, giving a sustained and stable catalytic activity during a long time-on-stream experiment.

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Section: Resultsmentioning

confidence: 99%

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

et al. 2021

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“…33 In recent years, a lot of results have been achieved in the preparation of one-dimensional TiO 2 by researchers. [34][35][36][37] There are also a lot of reports on two-dimensional TiO 2 nanomaterials, 38,39 but 3D TiO 2 and its composites with complex morphologies are almost rarely reported. 40 Inspired by the above, firstly, the unique morphology of a 3D nanorod structure of TiO 2 was prepared by combining electrospinning and hydrothermal methods.…”

Section: Introductionmentioning

confidence: 99%

A rationally designed 3DTiO₂@CdZnS heterojunction photocatalyst for effectively enhanced visible-light-driven hydrogen evolution

Li,

Ji,

Feng

et al. 2024

Dalton Trans.

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“…The law that the crystalline size of TiO 2 changes with the change of crystal phase type during the change of T a is also still under study [10]. Meanwhile, different researchers have different views on the photocatalytic activity of TiO 2 crystalline phases, and the anatase phase has the best photocatalytic activity among all TiO 2 crystalline phases because it is the most open structure of TiO 2 [11]. Tichapondwa et al showed that rutile crystalline phases do not have photocatalytic ability, but only adsorption [12].…”

Section: Introductionmentioning

confidence: 99%

Effect of annealing temperature on the structural, optical, morphological, and photocatalytic properties of TiO₂ thin films prepared by sol-gel spin-coating and electron beam physical vapor deposition

Dong,

Mamat,

Baikeli

2024

J. Phys. D: Appl. Phys.

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TiO2 thin films were prepared by sol-gel spin-coating (SGSC) and electron beam-physical vapor deposition (EB-PVD) methods and annealed at different temperatures (Ta ). X-ray diffraction spectroscopy (XRD) results show that the TiO2 films prepared by the SGSC method transformed from the anatase single phase to the coexistence of anatase and rutile with the increase of Ta . However, TiO2 films prepared by the EB-PVD method existed only in the anatase phase, and the crystalline strength was enhanced with the increase of Ta . Meanwhile, particles of TiO2 targets annealed at different Ta showed a rutile phase for TiO2 target particles in the EB-PVD method. The results indicate that the EB-PVD method hinders the nucleation growth and phase transformation of TiO2 films. Scanning electron microscopy and atomic force microscopy also show that the grain size and R ms of TiO2 thin films prepared by the SGSC method increased with the increase of Ta , and the grain size becomes inhomogeneous when the rutile phase is formed. Ultraviolet–visible results show that the forbidden bandwidth and light absorption capacity increase with increasing Ta . For the EB-PVD method, the grain size and surface roughness gradually increased when the Ta of the films was less than 800 °C, while annealing at 800 °C changed the direction of growth and nucleation, and also produced surface cracks; XRD verified the hypothesis that the EB-PVD method hinders the nucleation growth as well as the phase transition of the films. Weak differences in the optical absorption properties and bandgap values of the films also indicate that the EB-PVD method hinders the phase transformation of TiO2 films. Finally, the results of degradation of methylene blue (MB) under simulated visible light showed that the films prepared by the SGSC method gradually improved the photocatalytic performance with the enhancement of the crystalline strength of the anatase phase. The TiO2 films prepared by the EB-PVD method improved the photocatalytic performance with the increase of the active area.

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Hysteretic phase transformation of two-dimensional TiO2

Cited by 9 publications

References 15 publications

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

A rationally designed 3DTiO₂@CdZnS heterojunction photocatalyst for effectively enhanced visible-light-driven hydrogen evolution

Effect of annealing temperature on the structural, optical, morphological, and photocatalytic properties of TiO₂ thin films prepared by sol-gel spin-coating and electron beam physical vapor deposition

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Hysteretic phase transformation of two-dimensional TiO2

Cited by 9 publications

References 15 publications

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

Nanowire-Based Materials as Coke-Resistant Catalyst Supports for Dry Methane Reforming

A rationally designed 3DTiO2@CdZnS heterojunction photocatalyst for effectively enhanced visible-light-driven hydrogen evolution

Effect of annealing temperature on the structural, optical, morphological, and photocatalytic properties of TiO2 thin films prepared by sol-gel spin-coating and electron beam physical vapor deposition

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About

A rationally designed 3DTiO₂@CdZnS heterojunction photocatalyst for effectively enhanced visible-light-driven hydrogen evolution

Effect of annealing temperature on the structural, optical, morphological, and photocatalytic properties of TiO₂ thin films prepared by sol-gel spin-coating and electron beam physical vapor deposition