Amide-Bonded 2,4,6-Tris(carboxyphenyl)-1,3,5-triazine with B-Doped Carbon Nitride Z-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Production

Graphitic carbon nitride (g-C₃N₄, termed as CN) has emerged as a suitable photocatalyst strategy for hydrogen production from water splitting. However, it suffers from fast recombination of photogenerated carriers, poor visible light absorption, and low photocatalytic performance. Herein, we employ urea and NaBH₄ as precursors for boron-doped CN (BCN) and then graft with 2,4,6-tris(carboxyphenyl)-1,3,5-triazine (TPT) named as BCN/TPT nanocomposites via the solvothermal method. Several characterization techniques, such as X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, and Raman spectra, have thoroughly examined the BCN/TPT heterostructure’s construction, photophysical characteristics, and charge transfer. The covalent interactions in BCN and TPT facilitate the extension of the π-conjugated system and spatial separation of electrons and holes, which in turn augments photocatalytic hydrogen production from water splitting under visible light (λ ≥ 420 nm). The optimal BCN/TPT-15 composite shows the highest H₂ evolution rate of 193.67 μmol h^–1, which is nearly 6 and 17 times greater than BCN (30.33 μmol h^–1) and CN (11.33 μmol h^–1). In addition, the optimal sample achieves an apparent quantum yield (AQY) of 7.93% at λ = 420 nm with an excellent photocatalytic stability of 16 h. This study presents an amide-bonded strategy for developing high-performance Z-scheme heterojunction photocatalysts for efficient solar-driven H₂ production.