Photocatalytic H2O2 production with perylene(bis-imide)-doped periodic mesoporous silica using micropollutants as sacrificial donors

Abstract

A perylene-doped mesoporous silica material, PDI-SiO₂, is used as a heterogeneous photocatalyst for the light-driven production of H₂O₂ from polluted water samples. The photocatalyst operating principle is based on a reductive quenching mechanism where aqueous micropollutants act as sacrificial donors. The resulting reduced photocatalyst transfers electrons to aqueous O₂, leading to superoxide O₂˙⁻, which evolves into H₂O₂. Using a set of representative micropollutants (diclofenac, bisphenol-A and ofloxacin), appreciable amounts of H₂O₂ have been photoproduced (from 0.2 to 1.7 mM over 8 hours of irradiation) from concentrated samples (1 mM). Less concentrated samples (10 μM) were efficiently decontaminated when treated with PDI-SiO₂ in the presence of Fenton catalysts. We evidence that the efficiency of H₂O₂ photoproduction is related to the extent of the interactions between micropollutants and PDI-SiO₂.