Precursor-driven synthesis of Cu2SnS3 nanoparticles for the photocatalytic degradation of Rhodamine B under visible light irradiation

Abstract

Copper tin sulfide (Cu 2 SnS 3 ) is a non-toxic, earth-abundant ternary chalcogenide that has attracted significant attention as a visible-light-responsive photocatalyst for environmental remediation. Despite its rich chemistry, the influence of precursor type on the photocatalytic behaviour remains insufficiently explored. In the present study, we report on the synthesis of Cu 2 SnS 3 nanoparticles via the thermal decomposition of Cu(II) and Sn(IV) dithiocarbamate complexes as single-source molecular precursors in oleylamine at 260 °C. The crystalline and morphological properties of the as-prepared Cu 2 SnS 3 nanoparticles were investigated using XRD, SEM/EDX and TEM techniques. UV–vis-NIR and photoluminescence spectroscopy were employed to analyse the optical behaviour, while Raman and XPS spectroscopy were used to explore the surface chemistry. These analyses confirmed the formation of phase-pure, cubic Cu 2 SnS 3 with tunable crystallite size and lattice strain, as well as optical band gaps spanning 2.00–2.50 eV. Band-edge positions estimated from the optical data indicated favourable conduction and valence band potentials for the visible-light-induced generation of reactive oxygen species. The photocatalytic performance was evaluated by measuring the degradation of Rhodamine B under visible light. The catalyst’s performance was also assessed under various reaction conditions, including solution pH (5–11), initial dye concentration (10–25 mg/L), and catalyst type. Cu 2 SnS 3 derived from N-phenyl-substituted precursors exhibited superior activity, achieving over 95% RhB removal within 120 min at pH 5 using 20 mg of catalyst in a 100 mL solution of 10 ppm RhB, while retaining appreciable efficiency at higher pH values. Kinetic studies revealed pseudo-first-order behaviour with larger rate constants and correlation coefficients close to one.