Synthesis, characterization, computational studies, and photocatalytic properties of Cu doped Bi2S3 nanorods

Copper-doped Bi2S3 nanorods were synthesized by the solvothermal method, and the effect of the Cu ions on the structural, microstructural, optical, and photocatalytic properties of Bi2S3 nanorods were evaluated. XRD profile analysis was used to study the influence of Cu doping on the crystallite size as well as the strain within the Bi2S3. Theoretical and experimental analysis of the electronic properties of the doped Bi2S3 was carried out using first principle calculation and absorption spectroscopy. The morphology of the materials was studied using electron microscopy, while the photocatalytic activity was studied using methyl orange as a test pollutant. The structural analysis of the nanorods using the Scherrer equation and Williamson-Hall analysis showed a direct correlation between the dopant concentration and crystallite size, which was 23.49–34.16 nm (Scherrer’s) and 27.19–35.92 nm (Williamson-Hall’s). The crystalline strain also correlates directly with the dopant’s concentration with a range of 0.11–2.66, while the dislocation density varied inversely with dopant’s concentration with a range of 0.78–1.35. Electron microscopy studies showed the materials were significantly aggregated nanorods, with an aspect ratio of 2.95–7.70. First principle calculation and absorption studies showed Cu-doping impacted a red-shift on the bandgap of the Bi2S3, with a band gap in the range 1.35–1.78 eV. The materials showed efficient photocatalytic degradation of methyl orange, and an increment in the photocatalytic efficiency of pristine Bi2S3 from 88% to 98% by Cu ion doping. Radical scavenging experiments confirmed •OH radical as the most significant active specie in the degradation process. With improved photocatalytic activity, doping of Bi2S3 with Cu2+ could be a potential technique for developing effective materials with enhanced photocatalytic activity for the degradation of methyl orange from water.