Tailoring Metal Oxide Nanomaterials via Metal‐Ion Doping for Efficient Wastewater Remediation

Metal oxide nanomaterials (MONMs) have emerged as highly efficient, sustainable, and versatile materials for water treatment due to their unique physicochemical properties, large surface area, and strong catalytic activity. In recent years, metal‐ion doping has gained significant attention as an effective strategy to enhance and tailor the structural, optical, magnetic, and catalytic characteristics of metal oxides, thereby improving their performance in removing a wide range of water pollutants. This review provides a comprehensive overview of metal ion–doped metal oxides, including TiO 2 , ZnO, Fe 2 O 3 /Fe 3 O 4 , SnO 2 , CeO 2 , WO 3 , and BiVO 4 highlighting doping mechanisms and the resulting modifications in band structure, charge‐carrier dynamics, and surface reactivity. The enhanced capabilities of doped nanomaterials in photocatalysis, heavy metal removal, and antimicrobial activity are critically discussed. Additionally, the review addresses key challenges, including particle aggregation, stability, dopant leaching, and environmental safety, as well as recent advances in immobilization techniques and nanocomposite integration to improve applicability. Future perspectives emphasize the need for scalable synthesis, toxicity assessment, and the development of multifunctional, selective, and reusable nanomaterials. Overall, metal ion–doped MONMs represent a promising class of next‐generation materials for efficient and sustainable water purification technologies.