Green approach and ease synthesis of C/N-codoped TiO₂ nanocrystals for photodegradation of endocrine

Carbon species and nitrogen–codoped anatase TiO₂ (C/N-codoped TiO₂) nanocrystals with uniform particle size and high crystallinity were synthesized, employing hexamethylenetetramine (HMTA) as a nitrogen and carbon source throughout solvothermal reaction of TiCl₄ and HMTA at different contents (0.5 g, 1 g, 1.5 g, and 2 g HMTA). The synthesized photocatalysts were assessed by photocatalytic degradation of resorcinol as a probe of potent endocrine-disrupting chemicals (EDCs) compared with commercial P-25 photocatalyst. Raman spectra and XRD results confirmed that the obtained C/N-codoped TiO₂ is anatase TiO₂ phase with 10–20 nm nanocrystallite sizes. For resorcinol photo-oxidation in aerated aqueous solution, C/N-codoped TiO₂ nanocrystals synthesized at 0.5 g HMTA (H0.5) showed the superior photocatalytic efficiency among all synthesized photocatalysts. H0.5 photocatalyst exhibited the outstanding photocatalytic performance, which is 1.2 and 2 times greater than that of commercial P-25 and pure TiO₂. In addition, the rate constant of the H0.5 sample was enhanced 7.5 and 3 times than that of commercial P-25 and pure TiO₂, respectively. The C/N-codoped TiO₂ nanocrystals achieved high photocatalytic efficiency of up to 96% within 90 min. In contrast, the photocatalytic efficiency based on the commercial P-25 was 54%. The photocatalytic efficiency of C/N-codoped TiO₂ was considerably enhanced, owing to its increase of photogenerated charge separation rate, smaller crystal size, narrower bandgap energy, and stronger light harvesting in wide visible region. Detailed mechanistic and kinetic studies through photodegradation of resorcinol in water were addressed.