Molybdenum diselenide/polymeric carbon nitride dual-homojunction photocatalyst with multi-step charge transfer for...

Due to the high dissociation energy of carbon dioxide (CO₂) and sluggish charge transfer dynamics, photocatalytic CO₂ reduction with high performance remains a huge challenge. Herein, we report a novel dual-homojunction photocatalyst comprising of cyano/cyanamide groups co-modified carbon nitride (CN-TH) intramolecular homojunction and 1 T/2H-MoSe₂ homojunction (denoted as 1 T/2H-MoSe₂/CN-TH) for enhanced photocatalytic CO₂ reduction. In this dual-homojunction photocatalyst, the intramolecular CN-TH homojunction could promote the intralayer charge separation and transfer owing to the strong electron-withdrawing capabilities of the two-type cyanamide, while the 1 T/2H-MoSe₂ homojunction mainly contributes to a promote interlayer charge transport of CN-TH. This could consequently induce a tandem multi-step charge transfer and accelerate the charge transfer dynamics, resulting in enhanced CO₂ reduction activities. Thanks to this tandem multi-step charge transfer, the optimized 1 T/2H-MoSe₂/CN-TH dual-homojunction photocatalyst presented a high CO yield of 27.36 μmol·g^-1·h^-1, which is 3.58 and 2.87 times higher than those of 1 T/2H-MoSe₂/CN and 2H-MoSe₂/CN-TH single homojunctions, respectively. This work provides a novel strategy for efficient CO₂ reduction via achieving a tandem multi-step charge transfer through designing dual-homojunction photocatalyst.