Probing charge transfer of NiCo2O4/g-C3N4 photocatalyst for hydrogen production

Quantum dots/two-dimensional (0D/2D) semiconductor photocatalysts demonstrate wide solar light absorption region and high charge transfer efficiency. However, the relation between the interfacial electric field and the charge transfer during the photocatalytic hydrogen production process is still unclear. Here, we construct NiCo 2 O 4 quantum dots (QDs) and NiCo 2 O 4 nanoparticles (NPs) anchored with 2D g-C 3 N 4 (CN) to form NiCo 2 O 4 -QDs/CN and NiCo 2 O 4 -NPs/CN heterojunctions. The hydrogen production rate of CN loaded with NiCo 2 O 4 QDs is about 3 times higher than that of CN loaded with NiCo 2 O 4 NPs. The electric field intensity at the NiCo 2 O 4 -QDs/CN interface is calculated to be about 15,600 V cm −2 , about 9 times higher than that of NiCo 2 O 4 -NPs/CN, which could effectively drive the electrons of CN to flow toward NiCo 2 O 4 QDs, promoting photocarriers separation and hence greatly improving the photocatalytic performance. This work provides a method to understand the relationship between interfacial electric field strength and photogenerated charges of heterostructure photocatalysts.