Enhanced photocatalytic production of hydrogen peroxide via two-channel pathway using modified graphitic carbon nitride photocatalyst: Doping K+ and combining WO3

Abstract Photo-catalytic technology is an environmentally friendly and sustainable method for producing hydrogen peroxide (H2O2) and has got increasing attention. In the work, we prepared K+-doped g-C3N4 (KCN) by thermal copolymerization, and combined it with WO3 nanoparticles by a facile deposition method to obtain the final photocatalytic composite KCN/WO3. XRD, FT-IR, XPS, TEM, SEM, UV-Vis and EIS were used to characterize the obtained samples. The results of EIS, UV-Vis and XPS valence band spectrum indicated the K+ doping effectively promoted charge separation of g-C3N4 and the valence band position of the KCN/WO3 composite obviously shifted higher potential, which greatly enhanced photocatalytic production of H2O2 and made the composite can produce H2O2 at the level of mmol/L without bubbling O2. The KCN10/WO3 (10%) composite showed the maximum photocatalytic activity. The decomposition behavior of H2O2 and recycled stability of KCN10/WO3 (10%) were also investigated. Furthermore, a plausible mechanism of photocatalytic production of H2O2 for KCN10/WO3 (10%) was also proposed based on reactive radicals trapped experiment and quantitatively determined experiment of superoxide radicals ( O2-) and hydroxyl radicals ( OH).