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

Abstract

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.