A review on visible light active perovskite-based photocatalysts

Exceptional Visible-Light Activities of TiO2-Coupled N-Doped Porous Perovskite LaFeO3 for 2,4-Dichlorophenol Decomposition and CO2 Conversion

In this work, TiO₂-coupled N-doped porous perovskite-type LaFeO₃ nanocomposites as highly efficient, cheap, stable, and visible-light photocatalysts have successfully been prepared via wet chemical processes. It is shown that the amount-optimized nanocomposite exhibits exceptional visible-light photocatalytic activities for 2,4-dichlorophenol (2,4-DCP) degradation by ∼3-time enhancement and for CO₂ conversion to fuels by ∼4-time enhancement, compared to the resulting porous LaFeO₃ with rather high photoactivity due to its large surface area. It is clearly demonstrated, by means of various experimental data, especially for the ·OH amount evaluation, that the obviously enhanced photoactivities are attributed to the increased specific surface area by introducing pores, to the extended visible-light absorption by doping N to create surface states, and to the promoted charge transfer and separation by coupling TiO₂. Moreover, it is confirmed from radical trapping experiments that the photogenerated holes are the predominant oxidants in the photocatalytic degradation of 2,4-DCP. Furthermore, a possible photocatalytic degradation mechanism for 2,4-DCP is proposed mainly based on the resultant crucial intermediate, 2-chlorosuccinic acid with m/z = 153, that readily transform into CO₂ and H₂O. This work opens up a new feasible route to synthesize visible-light-responsive high-activity perovskite-type nanophotocatalysts for efficient environmental remediation and energy production.

Synthesis of Photoactive Materials by Sonication: Application in Photocatalysis and Solar Cells

In recent years, a good number of methods have become available for the preparation of an important group of photoactive materials for applications in photocatalysis and solar cells. Nevertheless, the benefits derived from preparing those materials through unconventional approaches are very attractive from the green chemistry point of view. This critical review work is focused on sonication as one of these promising new synthetic procedures that allow control over size, morphology, nanostructure and tuning of catalytic properties. Ultrasound-based procedures offer a facile, versatile synthetic tool for the preparation of light-activated materials often inaccessible through conventional methods.

A Visible-Light-Active Heterojunction with Enhanced Photocatalytic Hydrogen Generation

A visible-light-active carbon nitride (CN)/strontium pyroniobate (SNO) heterojunction photocatalyst was fabricated by deposition of CN over hydrothermally synthesized SNO nanoplates by a simple thermal decomposition process. The microscopic study revealed that nanosheets of CN were anchored to the surface of SNO resulting in an intimate contact between the two semiconductors. Diffuse reflectance UV/Vis spectra show that the resulting CN/SNO heterojunction possesses intense absorption in the visible region. The structural and spectral properties endowed the CN/SNO heterojunction with remarkably enhanced photocatalytic activity. Specifically, the photocatalytic hydrogen evolution rate per mole of CN was found to be 11 times higher for the CN/SNO composite compared to pristine CN. The results clearly show that the composite photocatalyst not only extends the light absorption range of SNO but also restricts photogenerated charge-carrier recombination, resulting in significant enhancement in photocatalytic activity compared to pristine CN. The relative band positions of the composite allow the photogenerated electrons in the conduction band of CN to migrate to that of SNO. This kind of charge migration and separation leads to the reduction in the overall recombination rate of photogenerated charge carriers, which is regarded as one of the key factors for the enhanced activity. A plausible mechanism for the enhanced photocatalytic activity of the heterostructured composite is proposed based on observed activity, photoluminescence, time-resolved fluorescence emission decay, electrochemical impedance spectroscopy, and band position calculations.

Enhanced photoredox chemistry in surface-modified Mg2TiO4 nano-powders with bidentate benzene derivatives

The absorption of Mg₂TiO₄ nano-powder was extended to visible spectral region upon surface modification with salicylate-and catecholate-type of ligands. Degradation of crystal violet over synthesized powders indicated their photocatalytic ability.

Low-temperature synthesis of mesoporous ZnTiO3–graphene composite for the removal of norfloxacin in aqueous solution

A novel mesoporous perovskite-type ZnTiO₃–graphene (MZT–GR) material was successfully fabricated via a two-step process in this paper.

Inorganic perovskite photocatalysts for solar energy utilization

This review specifically summarizes the recent development of perovskite photocatalysts and their applications in water splitting and environmental remediation.

Antimony sulphoiodide (SbSI), a narrow band-gap non-oxide ternary semiconductor with efficient photocatalytic activity

A highly crystalline 3D urchin-shaped SbSI with an ns² cationic electronic configuration displays very high and efficient photocatalytic degradation of organic pollutants.

A review of metal oxynitrides for photocatalysis

This review highlights the recent progress in the production of hydrogen using a metal oxynitride photocatalyst under visible light irradiation.

Visible light assisted photocatalytic hydrogen generation by Ta2O5/Bi2O3, TaON/Bi2O3, and Ta3N5/Bi2O3 composites

Bi₂O₃/TaON or Ta₃N₅ heterojunctions show significant enhancement in photocatalytic H₂ production under visible light irradiation compared to individual components.

Perovskite-type KTaO3–reduced graphene oxide hybrid with improved visible light photocatalytic activity

Novel rGO–KTaO₃ composites with various graphene content were successfully synthesized using a facile solvothermal method which allowed both the reduction of graphene oxide and loading of KTaO₃ nanocubes on the graphene sheets.

Fabrication of novel perovskite-type Sr2Ta(Fe1−xGax)O6nanoparticles with high visible-light photocatalytic activity

Novel Sr₂Ta(Fe_1−xGa_x)O₆perovskite photocatalysts with the excellent photocatalytic activity were successfully synthesized by a simple one-step sol–gel method.