Efficient photocatalytic hydrogen production by employing a graphdiyne/NH₂-MIL-88B(Fe) composite

The electron transfer rate in photocatalysts is one of the factors determining their hydrogen production activity. In this work, NH₂-MIL-88B(Fe) (NFM) was synthesized using a one-step hydrothermal synthesis method and NFM/GDY-25 (NFMG-25) was successfully synthesized by loading graphdiyne (GDY) onto the surface of NFM. The hydrogen production performance and the mechanism of the prepared photocatalysts were systematically investigated using XRD, SEM, FT-IR, XPS, UV-Vis, PL and photoelectrochemical tests. The results showed that the hydrogen production of NFMG-25 reached 61.7 μmol in 5 hours. Photoelectrochemical and Mott-Schottky tests demonstrated that the composite catalyst exhibited high photogenerated carrier separation efficiency and single catalysts were n-type semiconductors. The conduction bands of NFM and GDY were -0.36 V and -0.56 V, respectively, while the valence bands were 1.90 V and 1.12 V. NFM acted as an electron acceptor and donor, which accelerated the transfer of the electrons, and enhanced the photocatalytic hydrogen production efficiency of the composite system. This study provides an effective method for using NFM in photocatalytic hydrogen production.