One-step supramolecular pre-organizational synthesis of copper-doped porous carbon nitride for high photocatalytic nitrogen fixation

Solar-driven reduction of nitrogen to ammonia is a promising green approach and is considered as a sustainable alternative to the Haber-Bosch process. Carbon nitride (g-C3N4) is an ideal non-metallic semiconductor photocatalyst for photocatalytic N-2 reduction reaction (p-NRR). In this work, we designed a simple supramolecular self-assembly method to prepare copper-doped porous graphitic nitride (Cu@pg-C3N4) photocatalysts. The synergistic semiconductor and metal interactions enabled the obtained Cu@pg-C3N4 to achieve larger specific surface area, more efficient photo-generated carrier separation, and stronger photoreduction ability. The specific surface area of Cu@pg-C3N4 increased from 5.69 to 75.76 mu mol/L, exposing more active sites compared to bulk g-C3N4. The NH4+ production rate of the obtained Cu@pg-C3N4 was 150.47 mu mol/L, which is 20 times higher than that of the bulk carbon nitride, exhibiting excellent N-2 photofixation ability. These findings highlight the significant progress that can be achieved by metal supramolecular network modification strategies in harnessing the potential of carbon nitride for photocatalytic reduction applications.