Carbon nanotubes loaded N,S-codoped TiO₂: Heterojunction assembly for enhanced integrated adsorptive-photocatalytic performance

A visible-light active N,S-codoped TiO₂ incorporated with carbon nanotubes (CNTs) was synthesized by a multicomponent heterojunction scheme. The synthesized photocatalysts was examined by several analysis techniques. The conventional TiO₂, N-doped TiO₂, TiO₂/CNT and N,S-codoped TiO₂ were also synthesized, characterized, and integrated adsorptive-photocatalytic degradation rates were subsequently compared and assessed, for comparative purposes as reference photocatalysts. The parametric study was also carried out to investigate the effect of various operational factors, such as solution pH, the photocatalyst loading and initial concentration of dye solution, on the adsorptive-photocatalytic performance. The best activity performance was attained with the N,S-TiO₂/CNTs nanocomposite due to the synergistic effect of ternary components caused by the incorporation of dopants and CNTs in TiO₂ lattice, providing a high number of adsorption sites and facilitating the effective separation of photogenerated charge carriers and minimal recombination rates. N,S-TiO₂/CNTs exhibited around three times higher photocatalytic performance than that of the binary composites, i.e., N-TiO₂, TiO₂/CNTs, N,S-TiO₂, and about four times higher than the conventional TiO₂. Furthermore, the superior nanocomposites were also investigated for their recyclability for five consecutive cycles.