Visible light driven photocatalytic degradation of Rhodamine B and Direct Red using cobalt oxide nanoparticles

Dhas, C. Ravi; Venkatesh, R.; Jothivenkatachalam, Kandasamy; Nithya, A.; Benjamin, B. Suji; Raj, A. Moses Ezhil; Jeyadheepan, K.; Sanjeeviraja, C.

doi:10.1016/j.ceramint.2015.03.238

Cited by 128 publications

(18 citation statements)

References 46 publications

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“…Our results concur with those of other studies of the photocatalytic degradation of Rhodamine B [46,47,48] and Triphenylmethane dyes, such as Crystal Violet [39], Malachite Green [49], and Basic Violet 3 [50], that report similar N -demethylation, desulfonation, and chromophoric ring openings during dye degradation.…”

Section: Resultssupporting

confidence: 92%

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

et al. 2017

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Enzymatic degradation of organic pollutants is a new and promising remediation approach. Peroxidases are one of the most commonly used classes of enzymes to degrade organic pollutants. However, it is generally assumed that all peroxidases behave similarly and produce similar degradation products. In this study, we conducted detailed studies of the degradation of a model aromatic pollutant, Sulforhodamine B dye (SRB dye), using two peroxidases—soybean peroxidase (SBP) and chloroperoxidase (CPO). Our results show that these two related enzymes had different optimum conditions (pH, temperature, H2O2 concentration, etc.) for efficiently degrading SRB dye. High-performance liquid chromatography and liquid chromatography –mass spectrometry analyses confirmed that both SBP and CPO transformed the SRB dye into low molecular weight intermediates. While most of the intermediates produced by the two enzymes were the same, the CPO treatment produced at least one different intermediate. Furthermore, toxicological evaluation using lettuce (Lactuca sativa) seeds demonstrated that the SBP-based treatment was able to eliminate the phytotoxicity of SRB dye, but the CPO-based treatment did not. Our results show, for the first time, that while both of these related enzymes can be used to efficiently degrade organic pollutants, they have different optimum reaction conditions and may not be equally efficient in detoxification of organic pollutants.

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Section: Resultssupporting

confidence: 92%

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

et al. 2017

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“…A shoulder between 350 and 400 nm can also be observed, especially for those with higher Co(II) concentrations (0.5 and 1%). This absorption shoulder could have originated from the band gap excitation of CoO species estimated at ∼3.4 eV or more likely due to an interfacial charge transfer (IFCT) from the hexaniobate valence band to Co(II) centered orbitals due to the strong interaction of the metal ions with the hexaniobate surface, which will be discussed below through vibrational spectroscopic data. IFCT bands have been previously reported for grafted TiO 2 with several metals. ,, …”

Section: Resultsmentioning

confidence: 99%

Photoinduced H₂ Evolution by Hexaniobate Sheets Grafted with Metal Ions: The Fate of Photogenerated Carriers

Nunes

Bahnemann

Patrocínio

2021

ACS Appl. Energy Mater.

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Layered niobates are well-known photocatalysts for H2 evolution with a rich surface chemistry. Their photoactivity, however, is limited by their wide band gap energy (∼3.5 eV) and partial deactivation due to surface poisoning by photogenerated H2O2. In this way, a surface modification method able to induce novel electronic processes without changing the bulk properties can improve their performance. In this work, the surface of exfoliated hexaniobate (K4–x H x Nb6O17) layers was modified by grafting with metal ions such as Co(II) and Fe(III) and their photocatalytic properties were fully investigated. Morphological characterization showed that grafting ions are attached to the niobate surface forming amorphous clusters. These species induce an additional absorption feature in the UV-A region, which is attributed to an interfacial charge transfer from the niobate valence band to the metal ion centers. Enhanced UV-driven photoactivity was observed for 0.1% grafted samples, especially for those modified with Co(II) ions, while smaller H2 evolution rates are observed as the concentration of the grafting ions increases. When Pt was added to the photocatalyst, the H2 evolution rate for the 0.1% Co-grafted sample in plain water was 70% higher than that observed for the nongrafted Pt-hexaniobate. Full characterization by electron paramagnetic resonance, transient absorption spectroscopy, and photoelectrochemical measurements reveals that grafted ions can work as both electron and hole acceptors. In the presence of Pt as a preferential electron acceptor, Co(II) ions act as hole acceptors forming Co(III) centers, favoring the formation of OH• radicals from water and avoiding surface poisoning. At higher Co(II) concentrations and in the absence of Pt clusters, electrons are trapped at the Co centers, decreasing the H2 evolution rate. Thus, grafted Co(II) ions act as active redox shuttles in the hexaniobate sheets, contributing to more efficient charge separation.

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“…The energy bands between the different energy states in the bulk matter are actually generated by combining a group of nearby energy levels of many atoms. 14 The overlapping of neighboring energy levels decreases as the particle size approaches the nanoscale dimension, and the length of the energy band widens and as a result, the particle size decreases. The calculated band gap of Cu–Co 3 O 4 rises and this blue shift from 370 to 320 nm may be attributed to the Burstein–Moss effect caused by an increase in carrier concentration.…”

Section: Resultsmentioning

confidence: 99%

“…In recent years, metal oxide semiconductors have attracted special attention in modern scientific areas, because of a large variety of structural geometries with electronic properties that could exhibit metallic, semiconductor, or insulator characteristics, which endow them with diverse physical and chemical properties. 12 The controllable dimension and structural characteristics of metal oxides have been intensively studied for many applications due to their variable oxidation state and because of their application in various fields such as heterogeneous catalysis, 13 solar energy absorbers, 14 solid-state sensors, 15 and energy storage. 16 Over the past decades, inexpensive and environmentally friendly, relatively reproducible, and more stable large-scale synthetic routes have been sought.…”

Section: Introductionmentioning

confidence: 99%

“…Co 3 O 4 is a technologically important material with a wide range of applications in lithium-ion batteries, 12 heterogeneous catalysis, 13 gas sensing, 22 ceramic pigments, 38 electrochemical devices, and high temperature solar selective absorbers. 14 When reduced to the nanometer scale, Co 3 O 4 was found to have interesting optical properties having an indirect band gap of 1.5 eV. 39 Therefore, based on energy conservation concerns, there is a need to develop complete visible-light-driven photocatalysts with enhanced efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic insight into the photocatalytic degradation of organic pollutants and electrochemical behavior of modified MWCNTs/Cu–Co₃O₄ nanocomposites

et al. 2022

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Visible light driven photocatalytic degradation of Rhodamine B and Direct Red using cobalt oxide nanoparticles

Cited by 128 publications

References 46 publications

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

Photoinduced H₂ Evolution by Hexaniobate Sheets Grafted with Metal Ions: The Fate of Photogenerated Carriers

Mechanistic insight into the photocatalytic degradation of organic pollutants and electrochemical behavior of modified MWCNTs/Cu–Co₃O₄ nanocomposites

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Visible light driven photocatalytic degradation of Rhodamine B and Direct Red using cobalt oxide nanoparticles

Cited by 128 publications

References 46 publications

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

Differential Degradation and Detoxification of an Aromatic Pollutant by Two Different Peroxidases

Photoinduced H2 Evolution by Hexaniobate Sheets Grafted with Metal Ions: The Fate of Photogenerated Carriers

Mechanistic insight into the photocatalytic degradation of organic pollutants and electrochemical behavior of modified MWCNTs/Cu–Co3O4 nanocomposites

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Product

Resources

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Photoinduced H₂ Evolution by Hexaniobate Sheets Grafted with Metal Ions: The Fate of Photogenerated Carriers

Mechanistic insight into the photocatalytic degradation of organic pollutants and electrochemical behavior of modified MWCNTs/Cu–Co₃O₄ nanocomposites