Enhancing Light-Driven Production of Hydrogen Peroxide by Anchoring Au onto C3N4 Catalysts

Light-driven production of hydrogen peroxide (H2O2) is a green and sustainable way to achieve solar-to-chemical energy conversion. During such a conversion, both the high activity and the stability of catalysts were critical. We prepared an Au-supported C3N4catalyst—i.e., Au/C3N4-500(N2)—by strongly anchoring Au nanoparticles (~5 nm) onto a C3N4matrix—which simultaneously enhanced the activity towards the photosynthesis of H2O2and the stability when it was reused. The yield of H2O2reached 1320 μmol L−1on Au/C3N4-500(N2) after 4 h of light irradiation in an acidic solution (pH 3), which was higher than that (1067 μmol L−1) of the control sample Au/C3N4-500(Air) and 2.3 times higher than that of the pristine C3N4. Particularly, the catalyst Au/C3N4-500(N2) retained a much higher stability. The yield of H2O2had a marginal decrease on the spent catalyst—i.e., 98% yield was kept. In comparison, only 70% yield was obtained from the spent control catalyst. The robust anchoring of Au onto C3N4improved their interaction, which remarkably decreased the Au leaching when it was used and avoided the aggregation and aging of Au particles. Minimal Au leaching was detected on the spent catalyst. The kinetic analyses indicated that the highest formation rate of H2O2was achieved on the Au/C3N4-500(N2) catalyst. The decomposition tests and kinetic behaviors of H2O2were also carried out. These findings suggested that the formation rate of H2O2could be a determining factor for efficient production of H2O2.Keywords:hydrogen peroxide;Au catalyst;photosynthesis;carbon nitride