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

Abstract

The long-afterglow luminescent material Sr 2 MgSi 2 O 7 :(Eu, Dy) was combined with the photocatalytic material g-C 3 N 4 to construct a type of Sr 2 MgSi 2 O 7 : (Eu, Dy)/g-C 3 N 4 self-luminous photocatalytic composite. This overcomes the limitation that photocatalytic experiments can only be carried out under an external light source, and it provides a more flexible way to use photocatalytic technology in environmental purification. The morphology, structure, luminescence, and photocatalytic properties of the samples were investigated using a variety of advanced characterization techniques. The results show that the significant improvement in the photocatalytic performance is attributed to the formation of a Z-scheme heterojunction between the luminescent and photocatalytic materials and the promotion of the photocatalytic reaction by the properties of the long-afterglow luminescent material itself. A possible mechanism for the photocatalytic process of the composite is proposed, and it is speculated that the reason for the increased photocatalytic activity is internal electron transfer and electron−hole pair separation based on tests such as X-ray photoelectron spectroscopy and density functional theory calculations. This study provides a strategy for enhancing the photocatalytic activity of photocatalysts and achieving round-the-clock degradation of pollutants.

Tuning the catalytic performance of CaSnO3 by developing an S-scheme p–n heterojunction through Ag6Si2O7 doping

“…A lower fluorescence emission intensity indicates a reduced electron–hole recombination rate, which correlates with enhanced photocatalytic activity. 56…”

“…A lower fluorescence emission intensity indicates a reduced electron-hole recombination rate, which correlates with enhanced photocatalytic activity. 56 From Fig. 6(b), it is evident that CaSnO 3 and Ag 6 Si 2 O 7 exhibit emission peaks positioned at the highest wavelength.…”

Unveiling the Bifunctional Photo/Electrocatalytic Activity of In Situ Grown CdSe QDs on g-C3N4 Nanosheet Z-Scheme Heterostructures for Efficient Hydrogen Generation

“…The ESR signal of the CdSe QDs/CN heterostructure sample was stronger for • O 2 − (superoxide radicals) than that of the pure g-C 3 N 4 sample, indicating that under the same circumstances, CdSe QDs/CN can produce more superoxide radicals than pure g-C 3 N 4 (see Figure 5d). 50 In contrast, CdSe QDs produced more •O 2 − since its CB bottom is higher to the potential of O 2 /•O 2 − (−0.33 V vs NHE). The small •OH signal originates from the oxidation of •O 2 − to •OOH, which is further oxidized to •OH.…”

“…After 15 min of illumination, all samples with the exception of CdSe QDs showed ESR signals of hydroxyl radicals, indicating that no holes had been produced in the CdSe QDs (see Figure c). The ESR signal of the CdSe QDs/CN heterostructure sample was stronger for · O 2 – (superoxide radicals) than that of the pure g-C 3 N 4 sample, indicating that under the same circumstances, CdSe QDs/CN can produce more superoxide radicals than pure g-C 3 N 4 (see Figure d) . In contrast, CdSe QDs produced more ·O 2 – since its CB bottom is higher to the potential of O 2 /·O 2 – (−0.33 V vs NHE).…”