0D NiS2 quantum dots modified 2D g-C3N4 for efficient photocatalytic CO2 reduction

Photoreduction carbon dioxide to hydrocarbons has been recognized as one of the most promising and sustainable solutions to realize solar-to-chemical energy conversion and alleviate environmental pollution. Herein, we prepared g-C3N4 photocatalyst modified by NiS2 quantum dots as co-catalyst based on a seed-mediated hydrothermal process. The composite showed superior activity and stability in photocatalytic CO2 reduction. The highest CO evolution rate of 10.68 μmol h−1 g−1 was obtained on NSQD/CN-25 catalyst, which was 3.88-fold as high as unadulterated g-C3N4, and its apparent quantum efficiency (AQE) was 2.03% at 420 nm. During the photoconversion process, the possible intermediate products (such as COO-, CO2- and HCO3-) were detected by in situ FTIR analysis. Notably, the electron transfer from g-C3N4 to NiS2 QDs could effectively accelerate the separation of photoexcited electron–hole pairs. This work paves a new strategy toward designing cost-effective photocatalyst with high performance for photocatalytic CO2 reduction.