Construction of graphdiyne-layered bimetallic hydroxide-derived oxide composite photocatalyst for hydrogen evolution

Metal oxides have excellent photocatalytic properties. In this work, LDHs are used as precursors to prepare metal oxides (Cu 0.04 Zn 0.47 Co 2.49 O 4 ). Synthesis of graphdiyne (GDY) by mechanochemical method using calcium carbide as raw material. It is complexed with Cu 0.04 Zn 0.47 Co 2.49 O 4 to explore the hydrogen evolution performance of the composite catalyst CZC (Cu 0.04 Zn 0.47 Co 2.49 O 4 )/G (GDY) in water splitting under visible light and its possible hydrogen evolution mechanism. The results show that the composite catalyst CZC/G-11 has good hydrogen evolution activity, and its photocatalytic hydrogen evolution activity could reach up to 17.7 μmol h −1 at pH = 9. The four hydrogen evolution cycle stability tests show that CZC/G-11 maintains a relatively smooth level of hydrogen evolution. The photoelectrochemical and fluorescence test results show that the incorporation of GDY can effectively improve the charge separation efficiency of the composite catalyst CZC/G-11. Both CZC and GDY are n-type semiconductors, as shown by the Mott-Schottky test results. The catalysts are also tested by UPS and the energy band structure is analyzed, with conduction band values of −0.54 V and −0.58 V and valence band values of 1.41 V and 0.83 V for CZC and GDY, respectively. Combined with the electron transfer direction of each catalyst, the possible mechanism of photocatalytic hydrogen evolution between CZC and GDY is analyzed, and it is speculated that Z-scheme heterojunction is formed between CZC and GDY to promote the hydrogen evolution reaction.