One-pot synthesis of SnO₂ nanoparticles decorated multi-walled carbon nanotubes using pulsed laser ablation for photocatalytic applications

This work reports the synthesis and characterization of SnO₂/CNT nanocomposites and their photocatalytic performance. The nanocomposite catalysts were assembled via a pulsed laser ablation technique. Characterization was then undertaken by employing transmission electron microscopy (TEM), scanning electron microscopy (SEM), powder X-ray diffraction (XRD), and ultraviolet–visible spectroscopy. The photocatalytic activities of the SnO₂/CNT nanocomposite variants were studied based on the photodegradation of the methylene blue dye (MB). In this, the kinetics and mechanisms of the photocatalytic reactions were evaluated. The results from the various analyses were all correlated in confirming the composition, the incorporation of the dopant species and the structure of the nanocomposite catalysts. In particular, the crystallite sizes in the SnO₂ and the fabricated SnO₂-CNT 5 % and SnO₂-CNT 10 % materials were confirmed as 26.40 nm, 30.90 nm, and 28.69 nm, respectively. The UV light-induced photocatalytic reactions were rapid, leading to 94 % removal of the MB dye in 60 min and 120 min of UV irradiation, in the presence of the SnO₂-CNT 10 % and the SnO₂-CNT 5 %, respectively. The overall reactions follow pseudo-first order kinetics, yielding rate constants of 2.82 × 10⁻² min⁻¹ and 4.24 × 10⁻² min⁻¹, for the SnO₂-CNT 5 % and the SnO₂-CNT 10 % photocatalyzed reactions, respectively. The overall findings of this work demonstrate the effectiveness of laser-based synthesized SnO₂-CNT nanocomposites in the UV light-induced degradation of the MB dye pollutant and show a potential application for the removal of a wide range of other dyes from wastewater.