Phosphor-Enhanced, Visible-Light-Storing g-C₃N₄/Ag₃PO₄/SrAl₂O₄:Eu²⁺,Dy³⁺ Photocatalyst Immobilized on Fractal 3D-Printed Supports

Abstract

The combination of a phosphor with semiconductor photocatalysts can provide photoactivity in the dark. Indeed, the phosphor acts as a “light battery”, harvesting photons during irradiation and later re-emitting light that can be used by the catalytic phase when in conditions of total darkness. This allows for continued activity of the composite catalyst, even in conditions of unstable light stimulation. In this study, we assess the use of a heterojunction, namely graphitic-C3N4/Ag3PO4, that enables efficient photoactivity specifically under visible light stimulation, in combination with a phosphor that exhibits green–blue phosphorescence (510 nm), that is SrAl2O4:Eu2+,Dy3+. Our findings showed that this combination was particularly interesting, noticeably displaying significant photoactivity in darkness, after short periods of activation by visible light. After finding the right combination and optimal ratios for maximum efficiency, the resulting catalyst composite was immobilized on resin supports with a fractal surface, printed by LCD-SLA 3D printing. The immobilization was effectuated via an aqueous-phase plasma-aided grafting (APPAG) process, using cold plasma discharge (CPD) and using vinylphosphonic acid (VPA) as a coupling agent. Whereas the colloidal photocatalyst displayed a serious problem of partial physical separation between the catalytic phase, g-C3N4/Ag3PO4, and the phosphor, the immobilization of the composite catalyst on polymer supports allowed solving this issue. Photodegradation assessments confirmed that the hybrid supported phosphor-enhanced catalyst was active, notably in dark conditions, as well as fairly photostable. This study offers new prospects for the fabrication of polymer-based panels for water purification, with round-the-clock activity and that are, in addition, extremely easy to recover and reuse, by comparison with colloidal catalysts.

Dual fluorescence properties and enhanced thermal stability of SrSi2O2N2:Eu2+ phosphors by coupling with g-C3N4

“…33 The diffraction peak at 13.0°is assigned to the intraplanar stacking of tri-s-triazine unit structures, while the major diffraction peak at 27.54°belongs to the interplanar packing of the conjugated aromatic systems of g-C 3 N 4 . 32 It can be clearly found from Fig. 1 that the diffraction peaks of SSON/CN composites are wellindexed to the SrSi 2 O 2 N 2 crystal (JCPDS no.…”

“…In Fig.1, the intense peaks at 13.0°and 27.54°can be clearly observed for the diffraction of pristine g-C 3 N 4 , which is attributed to the (100) and (002) plane of the graphitic structure, respectively 33. The diffraction peak at 13.0°is assigned to the intraplanar stacking of tri-s-triazine unit structures, while the major diffraction peak at 27.54°belongs to the interplanar packing of the conjugated aromatic systems of g-C 3 N 4 32. It can be clearly found from Fig.1that the diffraction peaks of SSON/CN composites are wellindexed to the SrSi 2 O 2 N 2 crystal (JCPDS no.…”

“…Some researchers have combined g-C 3 N 4 with long-aerglow phosphors, such as SrAl 2 O 4 , CaAl 2 O 4 , and Sr 2 MgSi 2 O 7 , to achieve the photocatalytic activity in the dark environment and realize the purication of pollutants around the clock. [30][31][32][33][34][35] The combination of Ag 3 PO 4 /g-C 3 N 4 /SrAl 2 O 4 :Eu 2+ , Dy 3+ prepared by Lei et al shows high photoactivity both under visible light irradiation and in complete darkness, which simultaneously enhances the photocatalytic activity for the phosphor-enriched composite when compared to pure g-C 3 N 4 . 32 There are two types of strategies to obtain composite phosphors based on g-C 3 N 4 .…”

“…[30][31][32][33][34][35] The combination of Ag 3 PO 4 /g-C 3 N 4 /SrAl 2 O 4 :Eu 2+ , Dy 3+ prepared by Lei et al shows high photoactivity both under visible light irradiation and in complete darkness, which simultaneously enhances the photocatalytic activity for the phosphor-enriched composite when compared to pure g-C 3 N 4 . 32 There are two types of strategies to obtain composite phosphors based on g-C 3 N 4 . One of the strategies intends to improve the photoluminescence performance of the phosphor by compounding the phosphor with g-C 3 N 4 .…”

Development of Photoluminescent and Photochromic Polyester Nanocomposite Reinforced with Electrospun Glass Nanofibers

“…The benefits of alkaline earth aluminates include their lack of toxicity and radioactivity, which makes them an attractive option. LAs have been recommended for several applications [ 32 , 33 , 34 ] due to their photochromic and persistent phosphorescence characteristics. It has been observed that a change in the concentration of LAs can alter the photochromic and persistent phosphorescence properties of a bulk polyester resin.…”