Enhanced photocatalytic water-splitting performance of Fe/CdS nanomaterials: Structural, optical, and electrochemical insights

Photocatalytic water splitting using semiconductors for sustainable hydrogen production is a promising technology. Fe/CdS photocatalysts with varying Fe doping levels were synthesized and systematically characterized. The samples prepared via hydrothermal synthesis were then subjected to comprehensive structural, optical, electrochemical, and photocatalytic analyses. Fe doping induced slight shifts in X-ray diffraction (XRD) peak without altering the CdS crystal structure. The bandgap was reduced from 2.35 eV to 2.19 eV by increasing the Fe doping, enhancing visible-light absorption. X-ray photoelectron spectroscopy confirmed the incorporation of Fe into the CdS lattice. Electrochemical studies showed improved charge-transfer kinetics and redox peaks in cyclic voltammograms. Fe/CdS (0.20:1) achieved the highest hydrogen evolution rate at 54.75 mmol/g/h under visible light, outperforming pristine CdS (30.01 mmol/g/h) and FeS₂ (34.19 mmol/g/h). Stability tests over multiple hydrogen evolution cycles revealed structural integrity and activity retention, which were confirmed by XRD. Fe/CdS photocatalysts are promising for efficient water splitting because of their enhanced optical properties, charge-separation efficiency, and electrochemical activities. Optimization of Fe doping is crucial for maintaining a high photocatalytic efficiency and advancing renewable energy technologies toward greener systems.