Highly efficient visible photocatalytic disinfection and degradation performances of microtubular nanoporous g-C3N4 via hierarchical construction and defects engineering

Herein, microtubular nanoporous g-C3N4 (TPCN) with hierarchical structure and nitrogen defects was prepared via a facile self-templating approach. On one hand, the hexagonal tubular structure can facilitate the light reflection/scattering, provide internal/external active sites, and endow the electron with oriented transfer channels. The well-developed nanoporosity can result in large specific surface area and abundant accessible channels for charge migration. On the other hand, the existence of nitrogen vacancies can improve the light harvesting (λ > 450 nm) and prompt charge separation by acting as the shallow charge traps. More NHx groups in g-C3N4 framework can promote the interlayer charge transport by generating hydrogen-bonding interaction between C3N4 layers. Therefore, TPCN possessed highly efficient visible photocatalytic performances to effectively inactivate Escherichia coli (E. coli) cells and thoroughly mineralize organic pollutants. TPCN with the optimum bactericidal efficiency can completely inactivated 5 × 106 cfu mL−1 of E. coli cells after 4 h of irradiation treatment, while about 74.4 % of E. coli cells were killed by bulk g-C3N4 (BCN). Meanwhile, the photodegradation rate of TPCN towards methylene blue, amaranth, and bisphenol A were almost 3.1, 2.5 and 1.6 times as fast as those of BCN. Furthermore, h+ and •O2− were the reactive species in the photocatalytic process of TPCN system.