Metal-free brush-like 3D carbon nitride delivers efficient red-light-driven photocatalysis

In this study, melamine and cyanuric acid were used as precursors to form supramolecular crystals via hydrogen-bond-assisted self-assembly followed by hydrothermal treatment. Subsequent high-temperature calcination yielded a novel brush-like three-dimensional carbon nitride. The brush-like 3D architecture was found to expose more accessible active sites, markedly accelerate electron transfer, and suppress the recombination of photogenerated charge carriers. The resulting superoxide (${\mathrm{O}}_2^{- \bullet} $) and hydroxyl ($^{ \bullet} {\mathrm{OH}} $) radicals generated via electron reduction were identified as the key reactive species in the photocatalytic process. Moreover, the surface of the brush-like structure is enriched with nitrogen vacancies, which enhance the catalyst’s ability to harvest visible light. The photocatalytic performance of the brush-like CNS-650 catalyst was evaluated for rhodamine B (RhB) degradation. Under red-light irradiation (660 nm), its degradation rate was 7.4 times higher than that of bulk CN. This work provides valuable insights into the design and application of efficient metal-free 3D photocatalysts.