Electron acceptor design for 2D/2D iodinene/carbon nitride heterojunction boosting charge transfer and CO2 photoreduction

Harvesting value-added products by CO 2 reduction through photocatalysis is a sustainable approach. Against halogen-doping treatment, few-layer iodinene (FLI 2 ) was used innovatively to construct 2D/2D van der Waals heterojunction with carbon nitride nanosheets (CNNS) for CO 2 reduction under visible light irradiation. The photocatalyst achieved an enhanced CO production rate of 34.22 μmol g -1 h −1 , which was 7.76 times as pristine CNNS. Improved activity was attributed to FLI 2 /CNNS maintained tri-s-triazine crystal structure and polymeric framework of CNNS. FLI 2 /CNNS formed a contact interface by van der Waals force, where FLI 2 served as an electron acceptor and CNNS acted as an electron donor, beneficial for electron transfer. This carrier migration tendency in FLI 2 /CNNS was confirmed by the DFT calculation of Fermi level and electron density distribution, which led to increased charge separation and decreased charge recombination. This work proposes the novel 2D/2D FLI 2 /CNNS and highlights the potential of metal-free heterojunction for efficient photocatalysis.