Interface‐Driven Charge Dynamics in Biogenic Ag@g‐C ₃ N ₄ for Efficient Reductive Degradation of Toxic Nitroaromatics and Low‐Energy X‐Ray Attenuation

Silver nanoparticle (Ag NP)‐decorated graphitic carbon nitride (Ag@g‐C ₃ N ₄ ) nanocomposites were synthesized via chemical and biogenic routes and evaluated for reductive degradation of toxic nitroaromatic compounds and low‐energy X‐ray attenuation. Structural and spectroscopic analyses (XRD, FTIR, FESEM, TEM, XPS, DRS) confirmed uniform Ag NP incorporation and bandgap narrowing from 2.69 to 2.33 eV. Under visible light and in the presence of NaBH ₄ , biogenic Ag@g‐C ₃ N ₄ exhibited superior catalytic activity, achieving >95% degradation of p‐nitrophenol, dinitrophenol, picric acid, and dinitrophenylhydrazine within 5 min at pH 7, following pseudo‐first‐order kinetics. Mechanistic studies revealed that enhanced interfacial charge separation and Ag‐mediated electron transfer dominate the hydride‐driven reduction process, with minimal involvement of reactive oxygen species. In addition, Ag@g‐C ₃ N ₄ showed significantly improved X‐ray shielding performance, with higher mass attenuation coefficients and effective atomic numbers and reduced tenth value layers compared to pristine g‐C ₃ N ₄ in the 30–150 keV range. These results demonstrate that biogenic Ag@g‐C ₃ N ₄ is a sustainable, multifunctional material for efficient environmental remediation and lightweight radiation shielding applications.