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

Abstract

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 NiCo2O4 quantum dots (QDs) and NiCo2O4 nanoparticles (NPs) anchored with 2D g-C3N4 (CN) to form NiCo2O4-QDs/CN and NiCo2O4-NPs/CN heterojunctions. The hydrogen production rate of CN loaded with NiCo2O4-QDs is about 3 times higher than that of CN loaded with NiCo2O4-nanoparticles. The electric field intensity at the NiCo2O4-QDs/CN interface is calculated to be about 15600 V cm−2, about 9 times higher than that of NiCo2O4-NPs/CN, which could effectively drive the electrons of CN to flow toward NiCo2O4 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.