Band edge positions as a key parameter to a systematic design of heterogeneous photocatalyst

Abdullah, Eshraq Ahmed

doi:10.5155/eurjchem.10.1.82-94.1809

Cited by 21 publications

(8 citation statements)

References 73 publications

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“…Band edge positions play an essential role in determining the utility and performance of semiconducting materials for photocatalytic applications. 8,9 Generally, the degree and type of alignment of a material's band edge energies with the energy levels of species interacting with its surfaces can strongly influence the transfer of photo-generated charge carriers for reduction/oxidation reactions. For photocatalytic water splitting, for example, the band edges of the system in question should lie above and below the redox potentials for H 2 and O 2 respectively.…”

Section: Introductionmentioning

confidence: 99%

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Recio-Poo,

Morales-García,

Illas

et al. 2024

Nanoscale

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Section: Introductionmentioning

confidence: 99%

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Recio-Poo,

Morales-García,

Illas

et al. 2024

Nanoscale

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“…In general, there are two primary factors that impact potential photoreactivity of semiconductor materials at the nanoscale: ( i ) band-edge redox potentials and ( ii ) surface chemistry. The band-edge redox potentials define the limits of the thermodynamic driving force for a targeted redox process . Although wide-band-gap materials exhibit deficient light absorption, having a large band gap enhances their redox driving force.…”

Section: Introductionmentioning

confidence: 99%

Surface Adsorption and Photoinduced Degradation: A Study of Spinel Ferrite Nanomaterials for Removal of a Model Organic Pollutant from Water

Sanchez-Lievanos,

Sun,

Gendrich

et al. 2024

Chem. Mater.

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Spinel oxide nanocrystals are attractive materials for photoinduced advanced oxidation processes that degrade organic pollutants in water due to their chemical stability and tunability, visible light absorption, and magnetic recoverability. However, a systematic understanding of the structural and chemical factors that control the reactivity of specific spinel oxide nanocrystal materials toward photoinduced degradation processes is lacking. This Perspective illustrates these knowledge gaps through an investigation into the impacts of surface chemistry and composition of spinel ferrite nanocrystals of formula MFe 2 O 4 (M = Mg, Fe, Co, Ni, Cu, Zn) on their ability to remove a model organic pollutant (methyl orange (MO)) from water. We identify two mechanisms by which the nanocrystals remove MO from water: (i) surface adsorption and (ii) photoinduced degradation under visible light irradiation in the presence of hydrogen peroxide via the photo-Fenton reaction. Nanocrystals that do not contain any surface ligands are more effective at removing MO from water than nanocrystals that contain surface ligands, despite our observation that the ligand-less nanocrystals do not form stable colloidal dispersions in water, while ligand-coated nanocrystals are colloidally stable. For many of the spinel ferrite compositions studied here, the fraction of methyl orange removal via adsorption to the nanocrystal surface in the absence of photoexcitation is larger than the fraction removed under irradiation. Our data indicate that the composition-dependent surface charge of the nanocrystals controls the degree of surface adsorption of the charged MO molecule. Overall, these results demonstrate that careful consideration of the impacts of surface chemistry on the behavior of spinel ferrite nanocrystals is required to accurately assess and subsequently understand their activity toward the photoinduced degradation of organic molecules.

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“…From the insights into the typical photocatalytic process, the band edge potential primarily matters in achieving the required reduction and oxidation process . For instance, in a certain context, it is proposed that if the conduction band edge potential is more negative (on NHE scale at zero pH), it could happen to be an efficient H 2 evolution photocatalyst, while if the valence band edge lies in more positive potential, it could be efficient toward O 2 evolution reactions. , Notably, these suitable potentials of the band edges fundamentally ensure the appropriate energy of the charge carriers in the respective bands toward achieving the required reduction and oxidation reactions .…”

Section: Introductionmentioning

confidence: 99%

Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe₃O₄@TiO₂ Ternary Nanocomposites for Dye Degradation and H₂ Production under Light and Dark Conditions

et al. 2022

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This study explores the preparation of Ag plasmons-sensitized magnetic-Fe 3 O 4 integrated TiO 2 (Ag−Fe 3 O 4 @TiO 2 ) ternary nanocomposites and their defectinduced electron storage properties to exploit their photocatalytic memory effect toward dye degradation and H 2 generation under light and dark conditions. The crystalline phase formation and elemental states of the individual materials and elements in the nanocomposite are analyzed using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The existence of Ti and Fe ions with dual oxidation states of Ti 4+/3+ and Fe 3+/2+ , respectively, is observed by XPS, which revealed the presence of defects in the system. The observed red shift along with a distinct plasmonic band (corresponding to metallic Ag nanoparticles) in the UV−visible absorption spectrum and the observed modified radiative recombination emission in the PL spectrum confirmed the plasmon-driven visible light activity along with the improved carrier separation and transfer characteristics in the synthesized ternary composite. Accordingly, the Ag− Fe 3 O 4 @TiO 2 photocatalyst degraded almost 100% of MB (methylene blue) and RhB (rhodamine B) dyes under simulated solar light in 90 min, while it is found to be around 42% and 36% in 60 min under dark conditions, respectively (which is preirradiated for 60 min). Further, it produced H 2 at the rate of 911 μmol g −1 h −1 under light conditions and is decreased to ∼96 μmol g −1 h −1 under dark conditions which is preirradiated for 1 h. However, when the composite is preirradiated for 3 h, it showed a maximum H 2 evolution of 144 μmol g −1 h −1 under dark. Further, the photocurrent and electrochemical impedance under light and dark conditions suggested the mechanism of photocatalytic charge storage and transfer process in the composite. Although the photocatalytic memory effect of the composite is meager toward H 2 production due to the insufficient potential of the stored−released electrons to reduce the protons (2H + ) to H 2 under dark conditions, their degradation efficiency is considerably good.

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Band edge positions as a key parameter to a systematic design of heterogeneous photocatalyst

Cited by 21 publications

References 73 publications

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Surface Adsorption and Photoinduced Degradation: A Study of Spinel Ferrite Nanomaterials for Removal of a Model Organic Pollutant from Water

Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe₃O₄@TiO₂ Ternary Nanocomposites for Dye Degradation and H₂ Production under Light and Dark Conditions

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Band edge positions as a key parameter to a systematic design of heterogeneous photocatalyst

Cited by 21 publications

References 73 publications

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Tuning electronic levels in photoactive hydroxylated titania nanosystems: combining the ligand dipole effect and quantum confinement

Surface Adsorption and Photoinduced Degradation: A Study of Spinel Ferrite Nanomaterials for Removal of a Model Organic Pollutant from Water

Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe3O4@TiO2 Ternary Nanocomposites for Dye Degradation and H2 Production under Light and Dark Conditions

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Insights into the Photocatalytic Memory Effect of Magneto-Plasmonic Ag–Fe₃O₄@TiO₂ Ternary Nanocomposites for Dye Degradation and H₂ Production under Light and Dark Conditions