Highly Selective CO2 Capture and Its Direct Photochemical Conversion on Ordered 2D/1D Heterojunctions

Polymeric carbon nitrides (CNs) are regarded as the most sustainable materials for solar energy conversion via photocatalytic processes. However, the first-generation CNs suffered from imperfect charge separation and insufficient CO2 adsorption. Herein, the construction of a heterojunction material involving highly crystalline CN-nanorods with ordered alignment on graphene is delineated, which improves light harvesting, CO2 capture, and interface charge transfer. The graphene-supported 1D nano-arrays of crystalline CNs show a comparably high selectivity of CO2/N2 up to 44, with an isosteric heat of adsorption of 55.2 kJ/mol for CO2. The heterojunction material also drives the simple and efficient CO2 photoreduction in the gas phase, without the addition of any cocatalyst or sacrificial agent, even at the more relevant case of low concentrations of CO2. These findings provide a robust way for tailoring the performance of CN materials, with the aim of a practicable technological application for CO2 capture and photoreduction.