Decorating red-light-emissive, N-doped carbon dots on bismuth sulfide to promote the photocatalytic activity

Searching for photocatalysts with wide absorption range and high efficiency to solve the growing pollution issues such as organic pollutant degradation is vitally necessary for the upcoming clean and renewable energy systems. In this work, we employed one-step hydrothermal reaction to prepare bismuth sulfide (Bi2S3) incorporated with N-doped, red-light-emissive carbon dots (r-CDs) which manifest effective interface contact and excellent photocatalytic performance. The introducing of the r-CDs, which could be excited by long wavelength lights, efficiently widens the range of light absorption of the hybrid material and improves the ability of electron transfer, accounting for the remarkably higher photocatalytic efficiency of the hybrid material toward the degradation of methylene blue. A possible mechanism behind the efficient photocatalytic activity of the r-CDs/Bi2S3 is proposed where electrons transfer from Bi2S3 to the r-CDs for accelerating the separation of photo-generated electron/hole pairs. During the photocatalytic reaction, h+, •OH and •O2− simultaneously participated, as demonstrated by active species trapping experiments. This work provides a pace for designing high-performance photocatalysts based on the introducing of r-CDs with long wavelength emission, which is promising for catalytic and new energy applications.