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.