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

Abstract

Light-driven production of hydrogen peroxide (H 2 O 2 ) 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 C 3 N 4 catalyst-i.e., Au/C 3 N 4 -500(N 2 )-by strongly anchoring Au nanoparticles (~5 nm) onto a C 3 N 4 matrix-which simultaneously enhanced the activity towards the photosynthesis of H 2 O 2 and the stability when it was reused. The yield of H 2 O 2 reached 1320 µmol L −1 on Au/C 3 N 4 -500(N 2 ) 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/C 3 N 4 -500(Air) and 2.3 times higher than that of the pristine C 3 N 4 . Particularly, the catalyst Au/C 3 N 4 -500(N 2 ) retained a much higher stability. The yield of H 2 O 2 had 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 C 3 N 4 improved 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 H 2 O 2 was achieved on the Au/C 3 N 4 -500(N 2 ) catalyst. The decomposition tests and kinetic behaviors of H 2 O 2 were also carried out. These findings suggested that the formation rate of H 2 O 2 could be a determining factor for efficient production of H 2 O 2 .

Production of Hydrogen Peroxide by Photocatalytic Processes

“…[44] However,t wo recent studies found that Au NPs could be outstanding cocatalysts to improve the photocatalytic activity of g-C 3 N 4 for the synthesis of H 2 O 2 . [60] In one study reported by Chang et al, [60a] ac arbon-layer-stabilized method was adopted to load Au nanoparticles onto the C 3 N 4 matrix. They ield of H 2 O 2 with the fabricated Au/g-C 3 N 4 photocatalyst reached 1320 mmol L À1 after irradiation with light for 240 min;t his yield is 2.3-times higher than that of the pristine g-C 3 N 4 .Inthe other study,Zuo et al [60b] observed asimilar improvement in the production of H 2 O 2 production with aA u/C 3 N 4 photocatalyst.…”

A comparative perspective of electrochemical and photochemical approaches for catalytic H2O2 production

“…For instance, loading Au nanoparticles on the surface of g-C 3 N 4 resulted in highly efficient and stable H 2 O 2 production because of the favorable two-electron ORR and the inert nature for catalyzing the decomposition of the produced H 2 O 2 over the hybrid catalyst. 144,145 As a noble-metalfree co-catalyst, CoP has also been loaded on the surface of g-C 3 N 4 to improve the photocatalytic H 2 O 2 production efficiency under visible-light illumination by extending the light absorption range and promoting charge separation and electron transfer. 146 Last but not least, a new type of photoelectrochemical (PEC) system without an external bias has also been developed to simultaneously achieve the generation of H 2 O 2 and electricity in recent years.…”

Atomic-Level Understanding for the Enhanced Generation of Hydrogen Peroxide by the Introduction of an Aryl Amino Group in Polymeric Carbon Nitrides

“…In addition to all of the abovementioned catalysts, PCNs were also used to produce H 2 O 2 from mixtures of water and alcohols (Table ). More specifically, PCNs in conjunction with transition-metal catalysts, nitrogen vacancies, mesoporous morphologies, oxygen enrichment, or alkali metal dopants, have shown excellent reactivity. − Notwithstanding all of these excellent photocatalysts, a high-power light source (at least >150 W) was essential to achieve high reactivity, and a higher production rate of the generated H 2 O 2 was only possible with at least 250 W light power (very expensive lamps). From all of these data, it is clear that a robust catalyst is essential to reduce cost and increase production.…”