Construction of Eu₂O₃/g‐C₃N₄ Redox Heterojunctions Containing Eu³⁺/Eu²⁺ Self‐Redox Centers for Boosted Visible‐Light Photocatalytic Activity

Abstract

The in-built self-redox couple in a heterojunction can indeed boost its photocatalytic activity. Herein, to obtain highly efficient visible-light photocatalysis, a new Eu 2 O 3 /g-C 3 N 4 redox heterojunction is designed and fabricated by a facile in situ growth strategy. Compared with pure g-C 3 N 4 , the as-prepared Eu 2 O 3 /g-C 3 N 4 redox heterojunction shows extremely enhanced photocatalytic performance for the decontamination of organic contaminants under visible-light irradiation. The presence of the Eu 3+ /Eu 2+ self-redox couple is identified by X-ray photoelectron spectroscopy spectra analysis, before and after photoreaction. The boosted photocatalytic mechanism is explored systematically through UV/Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and photocurrent measure- [a]

Photocatalytic Composite Sr2MgSi2O7:(Eu, Dy)/g-C3N4: A Z-Scheme Heterojunction Material Formed by Long-Afterglow Phosphors and Photocatalysts on Round-the-Clock Photocatalytic Degradation of Methylene Blue

“…However, in combination with the radical trapping experiments and ESR tests, it does appear that OH – is produced. Therefore, these OH – are most likely from the reaction of ·O 2 – with H + or H 2 O. , The possible reaction pathways have been drawn in Figure c.…”

“…Therefore, these OH − are most likely from the reaction of •O 2 − with H + or H 2 O. 2,26 The possible reaction pathways have been drawn in Figure 10c.…”

“…Semiconductor-based photocatalysis consumes a low amount of energy, has easy operation, and produces no secondary pollution. Photocatalytic techniques can use solar energy to solve environmental and energy problems, and they have become a new treatment technology for environmental issues and have broad application prospects. − The technology is widely used in water purification, air purification, self-purification, sterilization and deodorization, anti-fouling, anti-fog, etc. − At present, photocatalysts are only active under excitation by an external light source, and this means that they are not photocatalytically active under harsh conditions (e.g., conditions with no light or with high concentrations of pollutants). Therefore, how to overcome this limitation and how to obtain efficient, green, and round-the-clock photocatalytic materials are important to promote the practical application of photocatalysis.…”

Enhanced Photocatalytic Degradation of Rhodamine B Dye by Iron-Doped Europium Oxide Nanoparticles

“…Among these wide-bandgap semiconductors, rare-earth oxide Eu 2 O 3 exhibited potential capacity in photocatalytic applications. − Nevertheless, due to europium’s unique 4f electron shell with split energy levels, the electric dipole transition could lead to photogenerated charge carrier recombination that is not favored in the photocatalytic degradation process. , Besides, the low light utilization caused by the wide bandgap of Eu 2 O 3 restrained its photocatalytic capacity. Up to now, most Eu 2 O 3 and europium cations-related photocatalytic studies are mainly about their auxiliary effect for enhancing other materials’ photocatalytic performances. − For Eu 2 O 3 itself as a photocatalyst, how to improve the material’s photocatalytic degradation efficiency is an interesting topic to be explored. There are several ways for improving a photocatalyst’s degradation capacity, such as to increase the active reaction sites, to enhance the light absorption, to inhibit/enhance the recombination/separation of photogenerated electrons and holes, and so forth.…”

Boosted visible-light photocatalytic activity and retarded carrier recombination of Eu3+-doped Nb3O7F nanomaterials prepared by hydrothermal method

“…Generally, the charge transfer and electron/ hole recombination play an important role in carrier separation efficiency and photocatalytic activity. Owing to the special 4f electron configurations, rare-earth ions are known for their ability to interact with f-orbital functional groups [10,11]. Moreover, rare-earth ions can also improve the separation efficiency of photogenerated electron-hole pairs by trapping electrons, increasing electron transfer, and retarding the carrier recombination [12][13][14].…”