In situ fabrication of two-dimensional g-C3N4/Ba5Ta4O15 nanosheet heterostructures with efficient charge separations and photocatalytic hydrogen evolution under visible light illumination

Abstract

Separation of photo-generated electron–hole pairs plays a crucial role in determining the practical performance of semiconductor photocatalysts. Here we have successfully fabricated two dimensional g-C₃N₄/Ba₅Ta₄O₁₅ nanosheet heterostructures through an in situ urea degradation method. The so-formed nanosheet heterostructures demonstrate superior photocatalytic activities in H₂ evolution reactions over individual component. Further analysis using photoelectrochemical measurements suggests efficient charge separations at the interfaces of these heterostructures which contribute to a prolonged lifetime of photo-generated charges as well as the much enhanced photocatalytic activities. The in situ fabrication method adopted in this work ensures a firm anchorage of g-C₃N₄ onto Ba₅Ta₄O₁₅ nanosheets and a face-to-face contact between these two semiconductors. Such a peculiar microstructure is critical to the high photocatalytic activity and apparently outweighs the conventional ones that involve only physical mixtures of two semiconductors and a point-to-point contact.