Horizontally growth of WS2/WO3 heterostructures on crystalline g-C3N4 nanosheets towards enhanced photo/electrochemical performance

Two-dimensional carbon-based material is attracting considerable attention in exploiting photocatalyst under visible light for photocatalytic energy conversion and storage field, e.g., photocatalytic H-2 production, and photodegradation. Here, WS2/WO3 composites are grown on crystalline graphitic carbon nitride (g-C3N4) nanosheets to form heterostructures using a hydrothermal treatment method. While the composition of WS2/WO3 depends on the preparation conditions, the ratio of WS2/WO3 affects the photocatalytic performance of samples. WS2/g-C3N4 heterostructures prepared with addition of ascorbic acid reveal enhanced photocatalytic activity due to efficient separation of photogenerated charge carriers. In contrast, sample with relatively low-WS2 proportion reveals high-H-2 generation performance under visible-light irradiation. Under full solar spectrum irradiation, the average H-2 evolution rate of sample is increased by 5.7 times comparing with that under visible-light test condition. The electrochemical performance of WS2/WO3/g-C3N4 heterostructures was studied using g-C3N4 with different crystallinity for comparison. With fixed WS2/WO3/g-C3N4 ratio, crystalline g-C3N4 leads to improved photocatalytic activity of WS2/WO3/g-C3N4 heterostructures. Sample using g-C3N4 with the highest crystallinity (prepared at 750 celcius) has the highest photodegradation rate and photocurrent response rate comparing with the samples prepared using low-crystalline g-C3N4 substrate.

Automated summary

The study investigates the photocatalytic capabilities of WS2/WO3/g-C3N4 heterostructures, revealing the significant impact of WS2/WO3 ratio and efficient separation of photogenerated charge carriers on photocatalytic performance, with crystalline g-C3N4 aiding in enhancing photocatalytic activity.