Cu²⁺ Modified g-C₃N₄ Photocatalysts for Visible Light Photocatalytic Properties

Abstract

Photocatalytic technology can effectively solve the problem of increasingly serious water pollution, the core of which is the design and synthesis of highly efficient photocatalytic materials. Semiconductor photocatalysts are currently the most widely used photocatalysts. Among these is graphitic carbon nitride (g-C3N4), which has great potential in environment management and the development of new energy owing to its low cost, easy availability, unique band structure, and good thermal stability. However, the photocatalytic activity of g-C3N4 remains low because of problems such as wide bandgap, weakly absorb visible light, and the high recombination rate of photogenerated carriers. Among various modification strategies, doping modification is an effective and simple method used to improve the photocatalytic performance of materials. In this work, Cu/g-C3N4 photocatalysts were successfully prepared by incorporating Cu 2+ into g-C3N4 to further optimize photocatalytic performance. At the same time, the structure, morphology, and optical and photoelectric properties of Cu/g-C3N4 photocatalysts were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy (DRS), and photoelectric tests. XRD and XPS were used to ensure that the prepared photocatalysts were Cu/g-C3N4 and the valence state of Cu was in the form of Cu 2+ . Under visible light irradiation, the photocatalytic activity of Cu/g-C3N4 and pure g-C3N4 photocatalysts were investigated in terms of the degradation of RhB and CIP by comparing the amount of introduced copper ions. The experimental results showed that the degradation ability of Cu/g-C3N4 photocatalysts was stronger than that of pure g-C3N4. The N2 adsorption-desorption isotherms of g-C3N4 and Cu/g-C3N4 demonstrated that the introduction of copper had little effect on the microstructure of g-C3N4. The small difference in specific surface area indicates that the enhanced photocatalytic activity may be attributed to the effective separation of photogenerated carriers. Therefore, the enhanced photocatalytic degradation of RhB and CIP over Cu/g-C3N4 may be due to the reduction of carrier recombination rate by copper. The photoelectric test showed that the incorporation of Cu 2+ into g-C3N4 could reduce the electron-hole recombination rate of g-C3N4 and accelerate the separation of electron-hole pairs, thus enhancing the photocatalytic activity of Cu/g-C3N4. Free radical trapping experiments and electron spin resonance indicated that the synergistic effect of superoxide radicals (O2 •− ), hydroxyl radicals (•OH) and holes could increase the photocatalytic activity of Cu/g-C3N4 materials.

Template-Free Synthesis of One-Dimensional g-C3N4 Chain Nanostructures for Efficient Photocatalytic Hydrogen Evolution

“…The key factor of photocatalytic reaction is the effective generation and rapid separation of photoexcited carriers (Huang et al, 2020a;Li X. et al, 2020;Wang L. et al, 2020;Wang et al, 2020b;Zhang et al, 2020c). The optical performances of the samples were measured by photoluminescence (PL).…”

Facile regeneration of oxidized porous carbon nitride rods by the de-aromatization of the heptazine network in bulk g-C3N4

“…The excellent photocatalytic activity of PCNRs was closely associated with one-dimensional rods with porous morphology as well as increased interfacial area. 52 Specifically, the 1D rod nanoarchitecture promotes the charge separation and mass transfer of carbon nitride semiconductors, 40,53,54 enabling them to act as more efficient photocatalysts for rhodamine B degradation than the pristine carbon nitride polymers. The PCNRs exhibit a unique optical absorbance and photoredox activity for rhodamine B degradation.…”

2D/2D FeNi-LDH/g-C₃N₄ Hybrid Photocatalyst for Enhanced CO₂ Photoreduction

“…The peak at 398.4 eV corresponds to the sp 2hybridized nitrogen atom bonded to two carbon atoms 33,34 . While the peak at 399.7 eV corresponds to the nitrogen atom connected to three carbon atoms 35,36 . The weak peak at 400.7 eV assigned to the C＝N-H group 37,38 .…”