Enhanced cocatalyst-support interaction and promoted electron transfer of 3D porous g-C3N4/GO-M (Au, Pd, Pt) composite catalysts for hydrogen evolution

Photocatalytic hydrogen production is regarded as an ideal strategy to solve energy issues. Graphene phase carbon nitrogen compound (g-C3N4) is commonly used to prepare improved photocatalysts due to its typical structural advantages. However, it generally presents low photostability of functional cocatalysts (e.g. precious metals) for simple 2D-layered structure of 2D g-C3N4. Herein, graphene oxide (GO) is applied to construct 3D porous g-C3N4/GO (p-CNG) skeleton via a thermal treatment aiding by template technique. Then, precious-metal (Au, Pd, Pt) cocatalysts were respectively immobilized to the 3D p-CNG skeleton to construct the 3D p-CNG-M (Au, Pd, Pt) composite catalysts. The typical 3D porous structure and bonding interaction between g-C3N4 and GO increase the specific surface area and improve the anchoring stability of cocatalysts. Meanwhile, precious-metal cocatalysts acted as the electron acceptors remarkably increase the active sites and promote the electron-hole separation. Thereby, the resultant 3D p-CNG-M composite catalysts present remarkably enhanced hydrogen evolution reaction (HER) activities under simulated solar light (SSL), and the optimal 3D p-CNG-Pt composite catalyst possesses the prominent HER activity (2565.81 mu mol g(-1) h(-1)) at pH = 10.5 for the stronger cocatalyst-support interaction, which is about 136-fold greater of 3D p-CNG skeleton (18.93 mu mol g(-1) h(-1)). Furthermore, its AQY is about 21.6 % under illumination (lambda = 420 nm). Especially, the excellent durability and reproducibility were achieved during long time photoinduction and multi-recycling. This study provides a potential strategy for enhancing the photostability and improving the SSL-induced HER performance of precious-metal modified photocatalyst.

Automated summary

The construction of a 3D porous g-C3N4/GO skeleton aided by graphene oxide, with the immobilization of precious-metal cocatalysts, significantly enhances the photocatalytic hydrogen production under simulated solar light. The improved anchoring stability of cocatalysts and increased active sites due to electron acceptors contribute to the enhanced performance of the resulting 3D p-CNG-M composite catalysts.