Efficient dark catalytic degradation of hazardous cationic dyes using a magnetic Fe3O4/rGO/CdS nanocomposite

In this study, Fe 3 O 4 /rGO/CdS magnetic nanocomposites were synthesized and evaluated as dark catalysts for the removal of synthetic hazardous dyes from water. Their catalytic performance toward both cationic and anionic dyes was investigated, revealing remarkable degradation efficiency for cationic dyes. The results showed that Fe 3 O 4 /rGO/CdS nanocomposites removed methylene blue and crystal violet cationic dyes entirely within 5 min from water. Also, rhodamine B dye was removed at about 91.8% after 15 min from the degradation process. The synthesized nanocomposites were characterized by TEM, FESEM, EDS, elemental mapping, Raman spectroscopy, XRD, VSM, FT-IR, cyclic voltammetry, electrochemical impedance spectroscopy, and zeta potential analysis. Structural and morphological analyses confirmed the successful fabrication of the Fe 3 O 4 /rGO/CdS nanocomposite, whereas electrochemical measurements demonstrated enhanced charge-transfer characteristics and improved interfacial electron transport. Zeta potential analysis revealed a negative surface charge (− 22.2 mV), which is expected to promote the adsorption of cationic dye molecules under the experimental conditions. Overall, the Fe 3 O 4 /rGO/CdS nanocomposite exhibited excellent dark catalytic performance for the rapid degradation of hazardous cationic dyes, demonstrating its potential as an efficient magnetically recoverable catalyst for water treatment.