ZIF-67 derived Co@NC/g-C₃N₄ as a photocatalyst for enhanced water splitting H₂ evolution

Graphitic carbon nitride (g-C₃N₄), as the one of the most promising photocatalysts, usually relies on noble metal co-catalysts in the photocatalytic water splitting H₂ evolution process, which greatly increases the use cost. Here, a zeolite imidazole framework (ZIF-67) derived Co@NC/g-C₃N₄ composite was constructed through facile thermal condensation of ZIF-67 and melamine. The obtained Co@NC/g-C₃N₄ composites can drive water splitting H₂ evolution without any noble metal co-catalyst under simulated sunlight. The optimal sample exhibits the highest H₂ evolution rate of 161 μmol g^-1·h^-1, which is 6 times of pure g-C₃N₄. The N doped carbon in carbonized ZIF-67 can not only quickly capture separated electrons from g-C₃N_4, but also serve as the co-catalyst. The well dispersed cobalt intermediate on carbonized ZIF-67 also play a role in promoting electron conversion. The formation of junction between carbonized ZIF-67 and g-C₃N₄ could promote quick charge carrier separation and transfer. This work provides a new idea for photocatalytic H₂ evolution without noble metal co-catalysis.