W18O49/crystalline g-C3N4 layered heterostructures with full solar energy harvesting towards efficient H2O2 generation and NO conversion

Abstract

The photocatalytic performance of graphitic carbon nitride (g-C3N4) heterostructures related to the charge carrier separation and transport efficiency is often governed by the interfaces. Herein, in-situ growth of W18O49 nanobelts is attained on amorphous and crystalline g-C3N4 nanosheets to study the effects of the interfaces on photocatalytic oxidation activities. The horizontal growth of W18O49 on g-C3N4 nanosheets is the key in formation of two dimensional (2D)/2D W18O49/g-C3N4 heterostructures. The growth of W18O49 nanobelts on crystalline g-C3N4 nanosheets shows well-developed interfaces (sample W18O49-CCN) in comparison with heterostructures constructed using amorphous g-C3N4 base (sample W18O49-ACN). Characterizations on the structure, components, and properties of the samples demonstrate that these heterostructures reveal extended photo-absorption in visible to near infrared region, with sample W18O49-CCN showing much higher photogenerated charge carrier separation and transport efficiency. A H2O2 evolution rate of 5550 µMg−1h−1 is observed for sample W18O49-CCN under full solar-spectrum illumination (and 398 µMg−1h−1 observed for pristine crystalline g-C3N4), which is ∼ 2.4 times of that of sample W18O49-ACN prepared using amorphous g-C3N4. In addition, a NO removal rate of 72.1% is observed for sample W18O49-CCN with a NO2 selectivity of 6.2%. These results provide inspiration for construction of g-C3N4 homojunctions for practical photo-redox reaction applications.