Enhanced Hydrogen Production via Photocatalysis Using g-C3N4/ZIF-67 Hybrid Composites

This research reports the development of photocatalytic active composites for hydrogen evolution obtained through high-energy mechanical milling of a mixture of the organic semiconductor g-C3N4 (CN) and the metal–organic framework ZIF-67. These composites, called CNZ-x (X = mass proportion of ZIF-67), were characterized using powder XRD, which showed that the crystalline phases of both the g-C3N4 and ZIF-67 precursors are present in the composites. SEM was used to determine the morphology, revealing that the ZIF-67 octahedral particles adhere to the surface of the CN sheets due to the intimate interfacial contact induced by high-energy mechanical grinding. The results of the photocatalytic evolution of H2 indicate that the CNZ-50 composite produced 261 μmol g−1 of H2, which is higher than the 229.5 and 124 μmol g−1 produced by the precursors ZIF-67 and CN, respectively. The higher efficiency in H2 evolution is due to the composite having better electron-hole separation than the precursor materials.