RETRACTED ARTICLE: Designing an eco-friendly Co/MnS/S-g-C₃N₄ nanocomposites: revolutionizing photocatalytic dye degradation and antibacterial efficiency

This study utilized an eco-friendly, simple, and cost-effectiveco-precipitation method to synthesize pure MnS and a series of Co/MnS nanoparticles(NPs) with varying cobalt contents (2%, 4%, 6%, 8%, and 10%). Thiourea was calcinedat 552 °C to prepareS-g-C₃N₄ (SCN) nanosheets. Theoptimal doped NPs were combined withS-g-C₃N₄ to create a series ofnanocomposites (10%, 30%, 50%, 70%, and 90%). The materials band gap (Eg) valueswere determined using Tauc plots. Photodegradation of MB dye was conducted with aUV-Vis spectrophotometer. According to the best of our knowledge, Sulfur-dopedgraphitic carbon nitride (S-g-C₃N₄) has been used for the first timein combination with cobalt and manganese sulfide nanoparticles to synergisticallyenhance visible-light photocatalytic activity, enabling efficient degradation of atoxic organic dye methylene blue. Besides photocatalytic treatment, theantibacterial results reveal that (Co /MnS/ S-g-C₃N₄) effectivelydestroyed bacteria with a synergy effect among cobalt elements, MnS andS-g-C₃N₄. Results indicated that doping 6% cobalt into the MnSlattice enhanced photocatalytic oxidation/reduction. The highest photodegradationperformance was observed in 6% Co/MnS@10% SCN nanocomposites, attributed to improvedcharge separation and reduced charge recombination. The synthesized nano-catalystsmaintained significant degradation percentages even after three cycles. Thestructural morphologies of pure MnS, 6% Co/MnS,S-g-C₃N₄, and 6% Co/MnS@ 10% SCNnanocomposites were analyzed using XRD and FTIR. Kinetic studies of the preparednanomaterials were conducted to determine their rate constants. The antibacterialperformance of the best photocatalysts was tested against Bacillus subtilis andEscherichia coli. The results suggest that composite synthesis and doping enhancedthe antibacterial activity of MnS, with the trend for antimicrobial activity beingMnS < 6% Co/MnS < 6% Co/MnS@10% SCN.