Preparation and enhanced visible-light photocatalytic activity of graphitic carbon nitride/bismuth niobate heterojunctions

Zhang, Shengqu; Yang, Yuxin; Guo, Yingna; Guo, Wan; Wang, Mei; Guo, Yihang; Huo, Mingxin

doi:10.1016/j.jhazmat.2013.07.025

Cited by 108 publications

(23 citation statements)

References 57 publications

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“…Comparatively, the photocurrent intensity of the W 18 O 49 device was roughly 8 times, about 500 times, and even 1000 times larger than that of the W 19 O 55 , WO 2.90 , and WO 3 one, respectively. For the WO 3−x crystals with more oxygen vacancies, the dramatic increase in photocurrent response for the light-on/off could mainly be ascribed to the enhanced absorption efficiency of light by the WO 3−x crystals under illumination and possibly their faster separation and transportation of photogenerated e − on the surface of the working electrodes [36,39]. This result is consistent with that of the UV-vis measurement in our previous work [11].…”

Section: Electrical Propertiessupporting

confidence: 90%

Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Shen

Zhao

Wen

et al. 2018

Journal of Nanomaterials

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Tungsten oxide (WO 3−x ) crystalline nano/microrods with identical morphology but different contents of oxygen vacancies were prepared by thermally evaporating fixed amount of WO 3 powder in reductive atmosphere from different amounts of S power at 1150 ∘ C in a vacuum tube furnace, in which both sources were loaded in separate ceramic boat. With increasing amount of S powder, a series of tungsten oxides, WO 3 , WO 2.90 , W 19 O 55 (WO 2.89 ), and W 18 O 49 (WO 2.72 ), could be obtained. And devices were fabricated by screen-printing the obtained WO 3−x crystals on ceramic substrates with Ag-Pd interdigital electrodes. With increasing content of oxygen vacancies, the devices fabricated with WO 3−x crystals present a negative to positive resistance response to relative humidity. Under dry atmosphere, for the devices with increasing , the strong response to light changed from short to long wavelength; under light irradiation, the conducting ability of the devices was enhanced, due to the more efficient separation and transportation of the photogenerated carriers; and under simulated solar irradiation, the photocurrent intensity of the W 18 O 49 device was roughly 8 times, about 500 times, and even 1000 times larger than that of the W 19 O 55 , WO 2.90 , and WO 3 one, respectively. With the versatile optoelectrochemical properties, the obtained WO 3−x crystals have the great potential to prepare various humidity sensors and optoelectrical devices.

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Section: Electrical Propertiessupporting

confidence: 90%

Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Shen

Zhao

Wen

et al. 2018

Journal of Nanomaterials

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“…Indeed, after 90 min irradiation only 42% of RhB was degraded. In the presence of Na 2 EDTA, the degradation rate decreased obviously, which is consistent with the previous results but contrary to those obtained in other studies. [1b,17] Moreover, the addition of ascorbic acid (a scavenger of O 2 •− ) caused a moderate change in the photocatalytic degradation of RhB and ≈63% of RhB photodegradation was attained.…”

Section: Resultsmentioning

confidence: 99%

A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

Huy

Thao

Dao

et al. 2017

Adv Materials Inter

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Photocatalysis involves the excitation of semiconductor materials by light absorption to produce electron-hole pairs, following charge-pair separation to induce the oxidation of organic pollutants. [1b] Among various semiconductors, oxides of the elements Ti, Bi, Zn, and Sn are preferable materials for photocatalytic processes. [1a] However, most of them generally show poor efficiency in photocatalytic reactivity due to wide band gaps of the materials and relatively high recombination rates of electron-hole pairs. Various promising approaches using composite materials, morphology control, noble metal loading, and heterostructural construction have been explored to enhance photocatalytic activity of the semiconductor materials. [1a] However, these strategies often require complicated preparation procedures. Therefore, the search for simple compounds with an enhanced ability to degrade organic pollutants has been the focus in photocatalytic research area. Recently, graphitic carbon nitride (g-C 3 N 4 ) with a stacked 2D structure has received much attention as a metal-free semiconductor and is rapidly becoming a favorite in material science. With medium band gap and thermal/chemical stability in an ambient environment, g-C 3 N 4 has become one of the most promising photocatalytic materials. [2] More importantly, doping with metal ions or nonmetal ions to form active sites for optimal heterojunctions leading to modify the band gap and morphology has been achieved for efficient separation of pairs electrons and holes to enhance the photocatalytic performance of g-C 3 N 4 significantly. A number of studies on the photocatalytic performance of g-C 3 N 4 have been reported to date. [3] Layered double hydroxides (LDHs), a group of layered functional materials with a special octahedral microstructure, have the following major features: the chemical composition of the layers is adjustable, the type and number of interlayer anions is exchangeable, and the particle size distribution is controllable. [4] Recently, LDHs have received worldwide attention because of their multiple applications, such as adsorbents, [5] catalysts, and catalytic supports. [6] The general formula of LDHs is [M 1−x 2+ M x 3+ (OH) 2 ] x+ (A n− ) x/n : yH 2 O, where M 2+ and M 3+ are divalent (Ca 2+ , Mg 2+ , Zn 2+ , Ni 2+ , Cu 2+ ) and trivalent (Al 3+ , Fe 3+ , Cr 3+ ) metal Novel photocatalysts in the form of zinc oxide-zinc bismuth oxide (mixedmetal oxide [MMO]) and graphitic carbon nitride (CN) hybrid composites are developed via a co-precipitation method followed by calcination at 520 °C. The as-prepared MMO-CN hybrid composites are evaluated on the basis of their photocatalytic activities for Rhodamine B (RhB) in aqueous solutions under visible light irradiation. The strong electronic coupling between two components within the MMO-CN heterostructure, which suppresses the photogenerated recombination of electrons and holes to a remarkable extent, is revealed. The prepared composites exhibit an excellent photocatalytic activity, leading to mo...

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“…[38][39][40] Figure 10 shows the influence of various scavengers on the visible light photocatalytic activity of as-prepared heterojunction catalysts. With the addition of EDTA-2Na, the RhB degradation rate for GCN-SCN, GCN/SCN(2), and GCN/SCN(1) decreased 45 from 92%, 58% and 50% to 36%, 20% and 17%, respectively.…”

Section: Resultsmentioning

confidence: 99%

Construction of g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

et al. 2015

RSC Adv.

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In the heterojunctions catalysts, the potential difference is the main driving force for efficient charge separation and transfer. The slight difference in the electronic band structure of the isotype heterojunctions catalysts causes the poor driving force, leading to the dissatisfactory charge separation 10 efficiency. In this work, g-C 3 N 4 /S-g-C 3 N 4 metal-free isotype heterojunctions catalysts (GCN-SCN) with the enhanced charge driving force were prepared by a two step calcination method. Anoxic photocatalytic degradation of RhB under visible light was used to evaluate the performance of as-prepared g-C 3 N 4 catalysts. The results indicate that this two step calcination method can markedly promote the charge driving force of as-prepared isotype heterojunctions, leading to the more efficient charge-carrier 15 migration. GCN-SCN displays the highest reaction rate constant of 0.0228 min -1 , which is 3.5 and 2.9 times higher than that of GCN/SCN(1) and GCN/SCN(2), prepared by one step calcination method. The linear relationship is observed between VB driving force and RhB degradation rate. This paper provides a new perspective to prepare the isotype heterojunctions with promoted charge driving force and photocatalytic performance.

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Preparation and enhanced visible-light photocatalytic activity of graphitic carbon nitride/bismuth niobate heterojunctions

Cited by 108 publications

References 57 publications

Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

Construction of g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

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Preparation and enhanced visible-light photocatalytic activity of graphitic carbon nitride/bismuth niobate heterojunctions

Cited by 108 publications

References 57 publications

Role of Oxygen Vacancies in the Electrical Properties of WO3−x Nano/Microrods with Identical Morphology

Role of Oxygen Vacancies in the Electrical Properties of WO3−x Nano/Microrods with Identical Morphology

A Mixed‐Metal Oxides/Graphitic Carbon Nitride: High Visible Light Photocatalytic Activity for Efficient Mineralization of Rhodamine B

Construction of g-C3N4/S-g-C3N4 metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions

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Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Role of Oxygen Vacancies in the Electrical Properties of WO_3−x Nano/Microrods with Identical Morphology

Construction of g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions