Abstract
The unidirectional electrons transfer from TCN to NiS and charge density difference of C3N4/NiS (001).
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•Explained the mechanism of Schottky junction based on the experiment and DFT data.•Given a detailed explanation about how and why the energy band of TCN was bent.•Clearly distinguished the two different charge transfer process from TCN to NiS.
Despite plenty of works involve in Schottky junction to optimizing charge kinetics have been researched, some issues still bother us. For example, why photo-excited electrons transfer from semiconductor to metal in Schottky junction, and can we realize the formation of Schottky junction is the nature property of materials and unrelated to light, etc. To analyze the mechanism of Schottky junction, a novel 3D weed g-C3N4/flowerlike NiS composite (TCN/NiS) was designed. The existence of Schottky junction was proved by DFT calculations. The high charge separation efficiency in TCN/NiS was reflected in the photo-electrochemical characterization, and was also verified by the photocatalytic degradation of a representative organophosphorus pesticides chlorpyrifos with a high degradation efficiency of 86 %. Especially, about how and why the energy band of TCN bending, and why photo-excited electrons transfer from TCN to NiS were explained elaborated. The deep understanding of Schottky junction helps to construct high efficiency photocatalysts.