Enhanced piezo-photocatalytic degradation of organic pollutants by cambered wall lamellar structure of porous tubular g-C3N4

The piezoelectric polarization electric field induced by the non-centrosymmetric triangular holes of g-C3N4 was beneficial to promote the separation and transport of photogenerated carrier. The porous structure of porous tubular g-C3N4 (PTCN) facilitated the absorption of visible light, and its thin and highly extended cambered tube wall lamellae and large specific surface area per unit cross-sectional area facilitated the response of mechanical vibration, thus improving the piezo-photocatalytic performance. The piezo-photocatalytic degradation rates of tetracycline hydrochloride (TCH), ciprofloxacin (CIP), rhodamine B (RhB) and methylene blue (MB) by PTCN were 89%, 51%, 100% and 100% within 30 min, respectively. The yield of H2O2 reached 196.6 μM within 120 min. Photocurrent intensity, finite element simulation, DFT calculation, PFM and free radical quantification experiments were conducted to explain the reason for the high piezoelectric performance of PTCN, and the reason for the higher piezoelectric properties of the tubular structure than the bulk structure was also analyzed in depth. This work filled the research gap of tubular g-C3N4 in piezo-photocatalysis and made up the research gap of the influence of material morphology structure on piezoelectric properties, which provided a new reference and incentive for future piezoelectric photocatalysis research.