Giant enhanced photocatalytic H2O2 production over hollow hexagonal prisms carbon nitride

Background: H2O2, as a green and environmentally friendly oxidant, has been widely used in our daily life and industrial production. It is of epoch-making significance to develop highly efficient photocatalysts for producing H2O2. In recent years, g-C3N4 has received much attention due to its high chemical stability, environmental friendliness and suitable energy band structure. However, some shortcomings including the fast recombination of photogenerated electron-hole pairs and small specific surface area in traditional 2D g-C3N4 seriously impede its photocatalytic performance for the production of H2O2. Methods: 1D hollow nanostructures possess intriguing physicochemical properties and are adopted to overcome the intrinsic shortcomings of g-C3N4. Herein, g-C3N4 with a hollow hexagonal prism structure (CN--HP) is prepared to produce H2O2. It is characterized by XRD, XPS, SEM, HRTEM, ESR and DRS. BET, PL spectra, photocurrent and EIS are used to explain the enhanced photocatalytic performance. Significant findings: Compared with traditional 2D g-C3N4, the specific surface area of CN--HP increases to 41.513 m2/g, providing more active sites. Meanwhile, its hollow tubular structure can enhance the migration of photogenerated electrons to the catalyst surface, and electrons with a longer lifetime can participate in photocatalytic reactions to achieve high efficiency. The yield of H2O2 production can up to 4.08 mmol over CN--HP in 40 min, which is about 7 times higher than that of traditional 2D g-C3N4, and the apparent quantum efficiency (AQE) of H2O2 production at 420 nm is 2.41%. This research provides a valuable reference for the development of green materials for efficient photocatalytic production of H2O2. (c) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Automated summary

A g-C3N4 catalyst with a hollow hexagonal prism structure (CN--HP) was prepared, which showed larger specific surface area, improved electron migration, and higher photocatalytic efficiency compared to traditional 2D g-C3N4. The production yield and apparent quantum efficiency of H2O2 were significantly enhanced over CN--HP.