Tube-shaped g-C 3 N 4 for enhanced piezocatalytic H 2 evolution

Tube-shaped g-C₃N₄ was synthesized via a combined hydrothermal and thermal polymerization strategy using melamine and urea as co-precursors. Owing to morphology-enhanced piezoelectric polarization and improved charge separation, the tubular catalyst exhibits a high piezocatalytic H₂ evolution rate of 2014.7 µmol g^-1 h^-1 under ultrasonic stimulation, corresponding to a 2.7-fold enhancement over intrinsic two-dimensional g-C₃N₄ nanosheets.