Green Fuel Combustion Synthesis of CeO ₂ and Ag/CeO ₂ Nanoparticles for Photocatalytic and Antibacterial Applications

ABSTRACT Silver‐doped cerium oxide nanoparticles (Ag/CeO 2 NPs) were synthesized using Ricinus communis seed extract as a bio‐derived fuel in a solution combustion method. The combustion reaction, carried out at 450°C with AgNO 3 and (NH 4 ) 2 [Ce (NO 3 ) 6 ] as metal precursors, produced CeO 2 and Ag/CeO 2 NPs. Their structure and morphology were estimated by P‐XRD and TEM, which confirmed the formation of cerianite with cubic fluorite CeO 2 crystal structure, while SEM revealed a porous morphology characteristic of combustion‐driven gas evolution. EDS revealed the presence of Ce, O, and Ag in the Ag/CeO 2 NPs. Optical studies, including UV–Vis and PL, showed that Ag incorporation narrowed the band gap and improved charge‐carrier separation, contributing to enhanced visible‐light activity. XPS analysis verified the successful incorporation of Ag species into the CeO 2 lattice. Among the investigated NPs, the 0.3 wt% Ag/CeO 2 sample exhibited the lowest PL intensity, indicating improved charge‐carrier separation, which was further supported by its high quantum yield (0.789). These results correlate with its enhanced photocatalytic activity. The nanomaterials were evaluated for dye degradation, Cr (VI) reduction, photocatalytic H 2 evolution, and antibacterial activity. The influences of pH, catalyst dosage, dye concentration, light intensity, radical scavengers, and recyclability were also systematically assessed. Overall, the study presents a sustainable synthesis approach for high‐performance Ag/CeO 2 NPs with broad potential in environmental remediation and antimicrobial applications.