N-doped carbon dots/CdS hybrid photocatalyst that responds to visible/near-infrared light irradiation for enhanced photocatalytic hydrogen production

The development of photocatalysts that harvest broad range of wavelengths from visible (Vis) to near-infrared (NIR) light region remains a high-priority target yet great challenge. In this work, a wide spectrum N-doped carbon dots (N-CDs)/CdS composite with low-cost, high efficiency and stability was rationally designed and fabricated by a simply solvothermal method. The result reveals that the introduction of N-CDs does improve the photocatalytic H-2 production of CdS. Especially, the N-CDs/CdS-5 (with a content of 5 wt%N-CDs) exhibited the highest H-2 production rates of around 58.9 and 20.1 mmol g(-1) h(-1) under irradiation of Vis and NIR light, respectively. Additionally, N-CDs/CdS composite also exhibited excellent durability for the photocatalyst activity over 160 h. The corresponding NIR photocatalytic activity of N-CDs/CdS mainly came from the up-converted photoluminescence (PL) property of N-CDs, which can upconvert NIR to Vis light for further exciting CdS nanoparticles to form photo-induced charges during the target reaction. The strategy used here thus opens up a new avenue to greatly tune both the Vis/NIR light absorption and charge separation to construct the effectively broad spectrum-driven photocatalysts.