Cost-effective and eco-friendly synthesis of thermally stable Sr2+ doped Bi2S3 nanoflowers for efficient adsorption and visible-light-driven photocatalytic degradation of Rhodamine-B pollutant

Background: Rhodamine-B is a hazardous pollutant used in textile industries that has adverse effects on humans and aquatic life. So, there is need to develop cost-effective and efficient photocatalysts. Methods: Sr<inf>x</inf>Bi<inf>2-x</inf>S<inf>3</inf> nanoflowers with varying Sr contents have been synthesized using hydrothermal method and have been studied by TGA, XRD, Rietveld refinement, UV-DRS, FESEM with EDX, PL and Zeta potential. The photocatalytic performance has been estimated by degrading RhB pollutants under visible light illumination. Significant Findings: The morphology of the prepared Sr<inf>x</inf>Bi<inf>2-x</inf>S<inf>3</inf> nanoparticles has been observed to be flower-like. They are stable up to 645 °C as assessed by TGA. Their Rietveld refinement revealed the orthorhombic crystal structure. E<inf>g</inf> determined using DRS falls in the range of 1.45 eV to 1.37 eV, while PL studies corroborate decreased e⁻-h⁺ pairs recombination in Sr doped samples compared to pure. The negative value of surface potential ascertained using zeta potential makes them suitable for cationic dye. The impact of dopant concentration on RhB under visible light exposure reveals x = 0.06 exhibits the highest degradation efficiency (η ∼ 92 %) in 240 min utilizing 5 mg/100 ml solution of 10 ppm dye concentration. The adsorption kinetic model is of 1st order, while photodegradation kinetics is governed by Zero^th order model.