Fabrication of ZnO, ZnS, Ag-ZnS, and Au-ZnS microspheres for photocatalytic activities, CO oxidation and 2-hydroxyterephthalic acid synthesis

Choi, Young In; Lee, Seungwon; Kim, Seog K.; Kim, Young Il; Cho, Dae Won; Khan, Mohammad Mansoob; Sohn, Youngku

doi:10.1016/j.jallcom.2016.03.070

Cited by 87 publications

(28 citation statements)

References 57 publications

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“…However, its wide band gap and high recombination rate of photo-generated charges often lead to low quantum yield in the photocatalytic reactions. To address the key issue of low quantum yield, many methods, such as noble metal deposition 7,8 , element doping 9 and semiconductor coupling 10,11 , have been extensively studied and applied in recent years 12–15 . Among these approaches, coupling with other semiconductors for forming the composites is one of the most effective ways to improve the separation efficiency of photo-generated charges, which could also take full advantage of solar spectrum, compared with the individual material 16,17 .…”

Section: Introductionmentioning

confidence: 99%

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light

Liu

et al. 2017

Sci Rep

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In this study, novel ZnS@In2S3 core@shell hollow nanospheres were fabricated by a facile refluxing method for the first time, and the formation mechanism of hollow structure with interior architecture was discussed based on ion-exchange Ostwald ripening. As the photocatalytic material for degradation of gaseous o-Dichlorobenzene (o-DCB), the as-synthesized core@shell hollow nanospheres were found to show significantly enhanced catalytic performance for effective separation of photo-generated charges. Moreover, the mechanisms of enhanced activity were elucidated by band alignment and unique configuration. Such photocatalyst would meet the demands for the control of persistent organic pollutant (POPs) in the atmospheric environment.

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Section: Introductionmentioning

confidence: 99%

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light

Liu

et al. 2017

Sci Rep

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“…Based on the plot of (αhv) 1/2 versus (hv), the calculated band gap energies of ZnS and ZnS@N-C-3 are, respectively, 3.32 eV and 3.06 eV. Due to the formation of a new mid-gap state, the conduction band (CB) of obtained ZnS with abundant sulfur vacancies is lower than that of ZnS, leading to the band gap energy of obtained ZnS being lower than that in previous works (3.2~3.6 eV) [51][52][53][54][55]. N-doped carbon can modulate the content of sulfur vacancies within the ZnS nanocrystals, leading to a reduced band gap energy of ZnS@N-C-3.…”

Section: Znsmentioning

confidence: 81%

N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

et al. 2019

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In this work, N-doped carbon-coated ZnS with a sulfur-vacancy defect (ZnS@N-C) was performed for the visible-light-driven photodegradation of tetracycline hydrochloride (TCH). The obtained ZnS@N-C exhibited enhanced photocatalytic activity compared with ZnS for TCH removal. Among these ZnS@N-C composites, ZnS@N-C-3 with N-doped content of 3.01% (100 nm) presented the best visible-light photocatalytic activity and superior long-term photocatalytic stability after five cycle times for TCH removal in the visible light region. This may be ascribed to the interface between the N-doped carbon shell and ZnS with a sulfur-vacancy defect for efficient charge transfer and the restrained recombination of charge carriers. Electron spin resonance (ESR) results indicate that the ·O 2 radical plays a crucial role in the enhanced photocatalytic activity of ZnS@N-C-3. Nanomaterials 2019, 9, 1657 2 of 13 composites between carbon and semiconductors. To further enhance the electron transfer and extend the visible light harvesting region, carbon doped with N atoms can adjust the work function of carbon and induce charge delocalization [23-26]. Hsu et al. have reported that sandwich-like hydrogenated C-doped anatase TiO 2 nanocrystals/N-doped carbon dots@layer/rutile TiO 2 nanorod arrays have exhibited efficient photoelectron-chemical activity of water oxidation [27]. This may be attributed to the N-doped carbon dots being the photosensitizer of long wavelength light-harvesting and the N-doped carbon layer being the conductive layer of charge transport toward the current collector. Wang et al. have also confirmed that N-doped carbon dots/g-C 3 N 4 can enhance visible-light photo-degradation activity for indomethacin due to the efficient charge separation and band gap narrowing of N-doped carbon dots [28]. Core-shell structured ZnO@N-doped carbon can efficiently adsorb and photodegrade methylene blue in the visible light region [29]. Electrons generated from nitrogen are transferred from the N-doped carbon surface to adsorbed oxygen, forming reactive radicals in the photocatalytic system [30-34]. In addition, surface polarity of N-doped carbon can promote dispersion in aqueous solution. However, few works have focused on the enhanced photocatalytic activity of ZnS with sulfur-vacancy defects using N-doped carbon coating. This work focuses on the synthesis of ZnS with an N-doped carbon coating (ZnS@N-C) and its sulfur-vacancy effect on visible-light photocatalytic activity for the removal of tetracycline hydrochloride (TCH). Reported photocatalysts such as CuInS 2 /Mg(OH) 2 [35], ZnIn 2 S 4 /BiPO 4 [36], AgBr/Bi 2 WO 6 [37], BiOI/g-C 3 N 4 /CeO 2 [38], and TiO 2 / BiOCl [39] are efficient heterojunctions for the visible-light-driven degradation of TCH. Differently from these compositions, N-doped carbon serves as the electron capture, facilitating the separation of electron-hole pairs. In this strategy, N-doped carbon is generated from the decomposition of cyanamide and coated on the surface of ZnS nano-particles, which are further tr...

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“…In addition, the activity of ·OH radical light catalyst plays a vital role; therefore, in addition to the active species in the experiment to prove the existence of ·OH radical, we adopt fluorescence techniques to terephthalic acid (TPA) as the probe molecule, NaOH‐TPA method to determine the content of ·OH radical, further analysis after modification charge separation behavior of solid solution. 2‐hydroxyterephthalic acid fluorescence is an effective chemical method to characterize the separation of photogenic charge . The more ·OH produced, the higher the efficiency of photogenic charge separation.…”

Section: Resultsmentioning

confidence: 99%

“…2-hydroxyterephthalic acid fluorescence is an effective chemical method to characterize the separation of photogenic charge. 10,42,54,55 The more ÁOH produced, the higher the efficiency of photogenic charge separation. The high separation efficiency of photogenic carrier will lead to the high content of hydroxyl radicals produced in the photocatalytic reaction system.…”

Section: Photocatalytic Activity Enhancement Mechanism Analysismentioning

confidence: 99%

Synthesis of “walnut‐like” BiOCl/Br solid solution photocatalyst by electrostatic self‐assembly method

et al. 2019

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Summary In this paper, under the control strategy of surface charge of BiOCl photocatalyst and the electrostatic adsorption of anions and cations in potassium bromide (KBr) and polyvinylpyrrolidone (PVP), the self‐assembly of “walnut‐like” BiOCl/Br solid solution nanophotocatalyst at a lower temperature water bath was proposed for the first time. X‐ray diffraction (XRD), Raman, scanning electron microscopy (SEM), high‐resolution transmission electron microscopy (HRTEM), energy‐dispersive system (EDS), X‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET), UV‐Vis, photoluminescence spectroscopy (PL) and Mott‐Schottky curve, transient photocurrent densities, and electrochemical impedance spectroscopy (EIS) were used to analyze the properties of materials, including its morphology, element distribution and chemical states, specific surface area, electrochemical property, and photogenic charge transfer. Based on the degradation performance of RhB dye wastewater and phenol in visible and ultraviolet light, and the band structure of BiOCl/Br solid solution, the reason for the improved photocatalytic activity was deeply discussed, and the possible degradation mechanism was also put forward. The above results show that Br− can be inserted into the crystal lattice of BiOCl under the effect of electrostatic adsorption to form solid solution by the interaction between atomic orbitals, which not only reduces the bandgap width but also improves the separation and mobility of photogenic electrons and holes, causing the absorbed light to shift red to the visible region. In addition, when the nBr−/nCl− = 0.67, “walnut‐like” BiOCl/Br solid solution was formed, and this kind of special core‐shell structure not only can increase the specific surface area, increase the number of active sites, but also can make the light reflect and refract many times in the cavity and further increase the utilization rate of light energy, and then the best photocatalytic activity was achieved. This study provides an new method to enhance the photocatalytic performance of BiOCl and be conducive to the development of modern material science.

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Fabrication of ZnO, ZnS, Ag-ZnS, and Au-ZnS microspheres for photocatalytic activities, CO oxidation and 2-hydroxyterephthalic acid synthesis

Cited by 87 publications

References 57 publications

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light

Preparation of ZnS@In2S3 Core@shell Composite for Enhanced Photocatalytic Degradation of Gaseous o-Dichlorobenzene under Visible Light

N-Doped Carbon-Coated ZnS with Sulfur-Vacancy Defect for Enhanced Photocatalytic Activity in the Visible Light Region

Synthesis of “walnut‐like” BiOCl/Br solid solution photocatalyst by electrostatic self‐assembly method

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