Photodegradation of 4-nitrophenol over B-doped TiO2 nanostructure: effect of dopant concentration, kinetics, and mechanism

Yadav, Vikas; Verma, Priyanka; Sharma, Himani; Tripathy, S.; Saini, Vipin K.

doi:10.1007/s11356-019-06674-x

Cited by 60 publications

(16 citation statements)

References 71 publications

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“…Nitroaromatic compounds such as 4-nitrophenol (4NP) are common pollutants found in several agricultural and industrial wastewater that pose a potent threat to aquatic life and ecosystems. , 4-Nitrophenol is a refractory organic compound that resists natural degradation processes owing to its high chemical and biological stability. , In addition to RhB, we studied the 4NP degradation efficiencies of the three photocatalysts, namely, CdS, CdS-MHP, and CdS-MHPINS. Figure a shows the UV–vis absorption spectrum of the dilute aqueous 4NP solution (5 ppm).…”

Section: Resultsmentioning

confidence: 99%

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires

Alam

Jensen

Kumar

et al. 2021

ACS Appl. Mater. Interfaces

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We present a potential solution to the problem of extraction of photogenerated holes from CdS nanocrystals and nanowires. The nanosheet form of C3N5 is a low-band-gap (E g = 2.03 eV), azo-linked graphenic carbon nitride framework formed by the polymerization of melem hydrazine (MHP). C3N5 nanosheets were either wrapped around CdS nanorods (NRs) following the synthesis of pristine chalcogenide or intercalated among them by an in situ synthesis protocol to form two kinds of heterostructures, CdS-MHP and CdS-MHPINS, respectively. CdS-MHP improved the photocatalytic degradation rate of 4-nitrophenol by nearly an order of magnitude in comparison to bare CdS NRs. CdS-MHP also enhanced the sunlight-driven photocatalytic activity of bare CdS NWs for the decolorization of rhodamine B (RhB) by a remarkable 300% through the improved extraction and utilization of photogenerated holes due to surface passivation. More interestingly, CdS-MHP provided reaction pathway control over RhB degradation. In the absence of scavengers, CdS-MHP degraded RhB through the N-deethylation pathway. When either hole scavenger or electron scavenger was added to the RhB solution, the photocatalytic activity of CdS-MHP remained mostly unchanged, while the degradation mechanism shifted to the chromophore cleavage (cycloreversion) pathway. We investigated the optoelectronic properties of CdS-C3N5 heterojunctions using density functional theory (DFT) simulations, finite difference time domain (FDTD) simulations, time-resolved terahertz spectroscopy (TRTS), and photoconductivity measurements. TRTS indicated high carrier mobilities >450 cm2 V–1 s–1 and carrier relaxation times >60 ps for CdS-MHP, while CdS-MHPINS exhibited much lower mobilities <150 cm2 V–1 s–1 and short carrier relaxation times <20 ps. Hysteresis in the photoconductive J–V characteristics of CdS NWs disappeared in CdS-MHP, confirming surface passivation. Dispersion-corrected DFT simulations indicated a delocalized HOMO and a LUMO localized on C3N5 in CdS-MHP. C3N5, with its extended π-conjugation and low band gap, can function as a shuttle to extract carriers and excitons in nanostructured heterojunctions, and enhance performance in optoelectronic devices. Our results demonstrate how carrier dynamics in core–shell heterostructures can be manipulated to achieve control over the reaction mechanism in photocatalysis.

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Section: Resultsmentioning

confidence: 99%

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires

Alam

Jensen

Kumar

et al. 2021

ACS Appl. Mater. Interfaces

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“…Other dopants for TiO 2 were also applied for advancing the photocatalytic process toward organic compounds that are presented in OPW, which is summarized in Table 3 . The success of the photodegradation process using the doped TiO 2 can be determined by the appearance of an intermediate as the result of organic pollutant oxidation by reactive oxygen species (ROS), such as the hydroxyl radical (•OH) as illustrated in the example for the degradation mechanism of 4-nitrophenol (4-NP) by B-doped TiO 2 in Figure 7 [ 67 ].…”

Section: Modification Approaches Of Tio 2 Photocat...mentioning

confidence: 99%

A Review of Titanium Dioxide (TiO2)-Based Photocatalyst for Oilfield-Produced Water Treatment

et al. 2022

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Oilfield produced water (OPW) has become a primary environmental concern due to the high concentration of dissolved organic pollutants that lead to bioaccumulation with high toxicity, resistance to biodegradation, carcinogenicity, and the inhibition of reproduction, endocrine, and non-endocrine systems in aquatic biota. Photodegradation using photocatalysts has been considered as a promising technology to sustainably resolve OPW pollutants due to its benefits, including not requiring additional chemicals and producing a harmless compound as the result of pollutant photodegradation. Currently, titanium dioxide (TiO2) has gained great attention as a promising photocatalyst due to its beneficial properties among the other photocatalysts, such as excellent optical and electronic properties, high chemical stability, low cost, non-toxicity, and eco-friendliness. However, the photoactivity of TiO2 is still inhibited because it has a wide band gap and a low quantum field. Hence, the modification approaches for TiO2 can improve its properties in terms of the photocatalytic ability, which would likely boost the charge carrier transfer, prevent the recombination of electrons and holes, and enhance the visible light response. In this review, we provide an overview of several routes for modifying TiO2. The as-improved photocatalytic performance of the modified TiO2 with regard to OPW treatment is reviewed. The stability of modified TiO2 was also studied. The future perspective and challenges in developing the modification of TiO2-based photocatalysts are explained.

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“…Brilliant green is used in paper printing and coloring silk, but its effects investigated on bacteria and rats alarming destruction were noted in their renal tissues and reproductive systems, so presence of these types of organic dyes in water impose threat that is why purification and detoxification of air and water are necessary to ensure safe of human and aquatic life. As listed by US-EPA, 4-nitrophenol is a cancercausing pollutant [8]. Researchers are continuously searching to find effective and ecofriendly ways to eradicate these toxic dyes and metals from water [9,10].…”

Section: Introductionmentioning

confidence: 99%

Phytogenic Synthesis and Characterization of NiO-ZnO Nanocomposite for the Photodegradation of Brilliant Green and 4-Nitrophenol

Haq

Raja

Rehman

et al. 2021

Journal of Chemistry

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The NiO-ZnO nanocomposite (NiO-ZnO NC) was synthesized by ecofriendly process by using Diospyros kaki (D. kaki) extract of leaves as reducing and capping agents. X-ray diffraction (XRD) was used for examined crystallinity, cell dimensions, and crystallite size (7.6 nm). To determine the purity of sample and weight percentage, energy dispersive X-ray (EDX) is used. The surface morphology was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By using Fourier transform infrared spectroscopy (FTIR), functional groups in samples were determined. By using diffuse reflectance data (DRS), band gap energy calculated via Tauc plot was 3.23 eV. The photocatalytic activity was checked against brilliant green (BG) and 4-nitrophenol (4-NP) and 92.5% and 69.7% of brilliant green (BG) and 4-nitrophenol (4-NP) were degraded with rate of degradation which were 0.0281 and 0.011 min−1.

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Photodegradation of 4-nitrophenol over B-doped TiO2 nanostructure: effect of dopant concentration, kinetics, and mechanism

Cited by 60 publications

References 71 publications

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires

A Review of Titanium Dioxide (TiO2)-Based Photocatalyst for Oilfield-Produced Water Treatment

Phytogenic Synthesis and Characterization of NiO-ZnO Nanocomposite for the Photodegradation of Brilliant Green and 4-Nitrophenol

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Photodegradation of 4-nitrophenol over B-doped TiO2 nanostructure: effect of dopant concentration, kinetics, and mechanism

Cited by 60 publications

References 71 publications

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C3N5 Core–Shell Nanowires

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C3N5 Core–Shell Nanowires

A Review of Titanium Dioxide (TiO2)-Based Photocatalyst for Oilfield-Produced Water Treatment

Phytogenic Synthesis and Characterization of NiO-ZnO Nanocomposite for the Photodegradation of Brilliant Green and 4-Nitrophenol

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Product

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Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires

Photocatalytic Mechanism Control and Study of Carrier Dynamics in CdS@C₃N₅ Core–Shell Nanowires