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.