Green synthesis of Cd and Cd/Zr-dual doped CeO2 nanoparticles for enhanced photocatalysis and latent fingerprint applications

Cd-doped and Zr/Cd co-doped CeO ₂ nanomaterials were synthesized using an eco-friendly solution combustion method with Lobularia maritima seed extract acting as a green fuel and reducing agent. The structural, morphological, elemental, and optical characteristics of the synthesized nanoparticles were thoroughly investigated using p-XRD, FT-IR, FE-SEM, EDX, UV-DRS, and PL spectroscopy. UV-DRS results indicated a systematic narrowing of the band gap with increasing co-doping (3.14 eV for Cd-CeO ₂ , 3.02 eV for Zr _0.05 -Cd _0.05 -CeO ₂ , and 2.88 eV for Zr _0.1 -Cd _0.1 -CeO ₂ ), confirming enhanced visible-light absorption due to dopant incorporation. p-XRD analysis revealed a reduction in crystallite size from ~ 23.4 nm to ~ 21 nm, suggesting that co-doping effectively influences crystal growth. Among the samples, Zr _0.05 -Cd _0.05 -CeO ₂ demonstrated the highest photocatalytic efficiency, achieving ~ 90% degradation of Rose Bengal under UV irradiation within 180 min through reactive oxygen species. Phytotoxicity studies verified the treated water’s environmental safety, while successful latent fingerprint visualization on rigid surfaces highlighted the nanoparticles multifunctional potential in environmental remediation and forensic science.