Weak Interaction between Nickel Thiolate and g-C<sub>3</sub>N<sub>4</sub> Improving Electron–Hole Separation for Photocatalysis
Fan Tian, Xiaofei Huang, Wangxuan Li, Yixuan An, Guangfang Li, Rong Chen
Abstract
Developing strategies to accelerate the electron–hole pair separation and understanding the mechanism are important for improving the activity of photocatalysts. Herein, constructing a weak interaction between nickel thiolate cluster (i.e., Ni 12 (SPhCH 3 ) 24 ) and graphitic carbon nitride (g-C 3 N 4 ) is revealed as an effective strategy to regulate electron–hole pair separation. The π–π interaction between the triazine rings in g-C 3 N 4 and the phenyl rings in Ni 12 (SPhCH 3 ) 24 offers a primary pathway for photogenerated electrons transfer from nickel cluster to g-C 3 N 4 . The photocatalytic hydrogen evolution rate of Ni 12 (SPhCH 3 ) 24 /C 3 N 4 achieves ∼3000 μmol g –1 h –1, which is about 230 times higher than that of pure g-C 3 N 4 . Theoretical analysis and femtosecond transient absorption spectroscopy show that the photogenerated electrons on the phenyl groups contribute to the unoccupied molecular orbitals (i.e., LUMOs+1) of Ni 12 (SPhCH 3 ) 24 and then transfer to the conduction band of g-C 3 N 4 via the π–π interaction, which eventually results in the spatial electron–hole pair separation and improves the hydrogen evolution activity of the catalyst.