Oxygen vacancies and interfaces enhancing photocatalytic hydrogen production in mesoporous CNT/TiO2 hybrids

Moya, Alicia; Cherevan, Alexey; Marchesan, Silvia; Gebhardt, Paul; Prato, Maurizio; Eder, Dominik; Vilatela, Juan J.

doi:10.1016/j.apcatb.2015.05.052

Cited by 126 publications

(55 citation statements)

References 44 publications

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“…1d and e). A small fraction of rutile is also detected, which forms due to the accelerated anatase-rutile phase transformation at the interface between nanocrystals, 16 and is thus to some extent inevitable in these samples. The average anatase crystal size calculated from XRD is 11.22 nm, which matches TEM observations.…”

Section: Resultsmentioning

confidence: 99%

“…16 Briefly, a solution of sol-gel precursors and PVP is electrospun as continuous thin nanofibres. Subsequent pyrolysis and annealing in inert gas removes the polymer coating and completes the crystallisation of TiO2, resulting in a vacancy-rich oxide with high activity in photocatalytic hydrogen production 16 and CO2 reduction under UV irradiation. 17 Fig .…”

Section: Resultsmentioning

confidence: 99%

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Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres

et al. 2016

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In this work we study the optoelectronic properties of individual TiO2 fibres produced through coupled sol-gel and electrospinning, by depositing them onto pre-patterned Ti/Au electrodes on SiO2/Si substrates. Transport measurements in the dark give a conductivity above 2·10 -5 S, which increases up to 8·10 -5 S in vacuum. Photocurrent measurements under UV-irradiation show high sensitivity (responsivity of 90 A·W -1 for 375 nm wavelength) and a response time to illumination of ~ 5 s, which is superior to state-of-the-art TiO2-based UV photodetectors. Both responsivity and response speed are higher in air than in vacuum, due to oxygen adsorbed on the TiO2 surface which traps photoexcited free electrons in the conduction band, thus reducing the recombination processes. The photodetectors are sensitive to light polarization, with an anisotropy ratio of 12%. These results highlight the interesting combination of large surface area and low 1D transport resistance in electrospun TiO2 fibres. The simplicity of the sol-gel/electrospinning synthesis method, combined with a fast response and high responsivity makes them attractive candidates for UV-photodetection in ambient conditions. We anticipate their high (photo) conductance is also relevant for photocatalysis and dye-sensitized solar cells.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres

et al. 2016

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“…[25][26][27][28][29] Interestingly, with simple composites, ternary hybrid composites offer the key advantage of intimate interfaces, namely facilitation of charge/energy transfer, which causes an increased lifetime of charge carriers through spatial separation of photoexcited electron-hole pairs. 30 In the present work, Pt-TiO 2 NPs/decorated carbon nanotube (fMWCNTs, fSWCNTs) nanocomposite materials are synthesized using a new method by a sonochemical/hydrationdehydration process, and are deliberately investigated by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD), UVvis diffuse reflectance spectroscopy (DRS), photoluminescence (PL), and Raman spectroscopy. The Pt-TiO 2 /fCNTs (fMWCNTs, fSWCNTs) composite materials were investigated by measuring the photocatalytic production of H 2 from biomass-containing aqueous solutions, namely from methanol either by Pt-TiO 2 / fCNTs nanocomposites, or by testing the in situ injection addition of Pt to the binary composite TiO 2 /fCNTs during the reaction of methanol dehydrogenation as a comparative study.…”

Section: Introductionmentioning

confidence: 99%

Sonochemical/hydration—dehydration synthesis of Pt—TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

Abdulrazzak

Hussein

Alkaim

et al. 2016

Photochem Photobiol Sci

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Modified Pt-TiO 2 NPs/decorated carbon nanotubes were synthesized utilizing sonochemical/hydrationdehydration techniques. Pt was loaded on TiO 2 by a photodeposition method keeping in mind the end goal to achieve electron-hole pair separation and promote the surface reaction. The morphological and basic properties of Pt-TiO 2 /fCNTs were investigated by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and Raman spectroscopy. The selected area electron diffraction (SAED) patterns of Pt-TiO 2 /fCNTs were obtained utilizing TEM-based energy dispersive X-ray spectroscopy (EDXS) analysis. It was found that the TiO 2 nanoparticles were uniformly distributed on the fCNTs, and the Pt particles were decorated on the surface of TiO 2 /fCNTs. The photocatalytic hydrogen production activity of the Pt (0.5%) -TiO 2 /fCNTs (0.5%) nanoparticle composites was investigated using a sacrificial agent methanol solution. Pt-loaded TiO 2 demonstrated a hydrogen evolution rate around 20 times that of TiO 2 /fCNTs (0.5%) (fSWCNTs, fMWCNTs). When compared with platinized TiO 2 in methanol, which was utilized as a control material, Pt-TiO 2 /fCNTs demonstrated an almost 2-fold increment in hydrogen generation.

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“…Lately the use of carbon nanotubes (CNTs) to increase the effectiveness of surface reactions has been more frequently observed 1 13 and by electrospinning 14,15 . Nevertheless, these techniques are not easy and require specialized equipment.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Performance of TiO2-ZnO/CNT Hetero-Nanostructures Applied to Photodegradation of Organic Dye

2016

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Water pollution by organic compounds is one of the major challenges faced by industries that use dyeing processes. Thus, some methods were developed for degrading dyes in wastewaters, including heterogeneous photocatalysis by semiconductor oxides. However, these oxides have limited photocatalytic activity due to the fast recombination of photogenerated electron-hole pairs. The aim of this study is the use of a carbon nanotube (CNT) and TiO 2 -ZnO oxide junction from modified sol-gel method to promote the degradation of organic dye through the photocatalytic activity of these nanocomposites. TiO 2 -ZnO/CNT nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and photocatalytic decomposition of organic dyes. The results of photocatalysis show up to 60% the efficiency of the samples in the removal of dye.

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Oxygen vacancies and interfaces enhancing photocatalytic hydrogen production in mesoporous CNT/TiO2 hybrids

Cited by 126 publications

References 44 publications

Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres

Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres

Sonochemical/hydration—dehydration synthesis of Pt—TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

Preparation and Performance of TiO2-ZnO/CNT Hetero-Nanostructures Applied to Photodegradation of Organic Dye

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Oxygen vacancies and interfaces enhancing photocatalytic hydrogen production in mesoporous CNT/TiO2 hybrids

Cited by 126 publications

References 44 publications

Highly responsive UV-photodetectors based on single electrospun TiO2 nanofibres

Highly responsive UV-photodetectors based on single electrospun TiO2 nanofibres

Sonochemical/hydration—dehydration synthesis of Pt—TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

Preparation and Performance of TiO2-ZnO/CNT Hetero-Nanostructures Applied to Photodegradation of Organic Dye

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Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres

Highly responsive UV-photodetectors based on single electrospun TiO₂ nanofibres