WS2 quantum dots seeding in Bi2S3 nanotubes: A novel Vis-NIR light sensitive photocatalyst with low-resistance junction interface for CO2 reduction

Abstract Efficient photocatalysts sensitive to visible and near infrared lights have attracted increased concerns owing to the high utilization efficiency of solar energy. Herein, WS2 quantum dots (WS2 QDs) doped Bi2S3 nanotubes with smooth surface were constructed by seed-mediated strategy with WS2 QDs as seeds, which show sensitive response to Vis-NIR lights. In WS2@Bi2S3 structure, exposed S atoms in WS2 QDs combined Bi3+ ions to form Bi-S bonds, and enabled the S-sharing between WS2 and Bi2S3 unit cells. The perfect junction interface between WS2 and Bi2S3 is straight and smooth without any disordered atoms, endowing low resistance for fast electron transfer on the interface and efficient separation of electron-hole pairs. Compared with pristine Bi2S3 nanotubes, the WS2@Bi2S3 nanotubes display enhanced photocatalytic activity in CO2 reduction, with 38.2 μmol g−1 of methanol and 27.8 μmol g−1 of ethanol achieved at optimal WS2 loading content (4 wt%) under Vis-NIR light irradiation for 4 h. It is proposed that the low-resistance interface between WS2@Bi2S3 heterojunction and the regulated electron pathway along Bi2S3 nanotubes account for the high photocatalytic activity, which enables WS2@Bi2S3 a promising and unique photocatalyst, and indicates a new direction for light harvest.