Nano-cubic SrTiO3 on poly(heptazine imide) (PHI) composite for enhancing photodegradation efficiency†

Photocatalytic degradation effectively removes organic pollutants from wastewater, ensuring environmental safety. The current study successfully generated SrTiO₃ NCs/PHI nanohybrids by a simple sonication method and used them for photocatalytic degradation of organic pollutants. The obtained samples were characterized by XRD, SEM, TEM, XPS, FT-IR, and UV-vis DRS. The results clearly indicated that SrTiO₃ nanocubes are effectively spread within the layers of PHI. The catalysts were tested for photocatalytic degradation of crystal violet (CV), methylene blue (MB), rhodamine B (RhB), and Congo red (CR) under UV-visible irradiation. In comparison with other catalysts, SrTiO₃ NCs/PHI exhibited exceptional decolorization of all four dyes, and pseudo-first-order kinetics were revealed. The nanocomposite activity exceeded those of SrTiO₃ NCs and PHI in increasing charge carrier production, separation, and transport, as validated by PL, EIS, and photocurrent methods. The results of trapping tests showed that ˙OH, ˙O₂⁻, and h⁺ species are crucial to the degradation process. The type-I heterojunction mechanism was suggested based on the results and Mott–Schottky plots, which were more consistent with the real conditions of the photocatalytic process. This research aims to establish a substantial strategy for enhancing the band structure of SrTiO₃ with PHI to improve its photocatalytic efficacy.