Study on Ag2WO4/g-C3N4 Nanotubes as an Efficient Photocatalyst for Degradation of Rhodamine B

Ag 2 WO 4 is a typically noble metal based photocatalyst with highly efficient photocatalytic activity. However, due to photocorrosion, the pristine Ag 2 WO 4 is prone to inactivation during illumination. Constructing composite photocatalyst may be a useful method to promote the stability of Ag 2 WO 4 . In this work, Ag 2 WO 4 /graphitic carbon nitride nanotubes (g-C 3 N 4 NTs) composite photocatalyst was prepared by adopting an in-situ composite strategy. The photocatalytic performance of the samples was discussed by the degradation of rhodamine B under visible light, and the catalytic mechanism was also analyzed. The characterization results show that the photocatalytic efficiency of the as-prepared Ag 2 WO 4 /g-C 3 N 4 NTs composite increases firstly and then decreases along with the increase of the Ag 2 WO 4 content. When the theoretical molar ratio of Ag 2 WO 4 :g-C 3 N 4 NTs reaches 3:2, the photocatalytic degradation efficiency achieves the optimal value, that is 92.4% within 20 min, which obviously exceeds 2.8% of pure Ag 2 WO 4  and 48.9% of pure g-C 3 N 4 NTs. Moreover, the separation and migration efficiency of photoelectron–hole pairs of the composites can be accelerated in comparison with pure samples. In addition, superoxide radicals and hydroxyl radicals play major roles in the photocatalytic degradation process.