Facile fabrication of novel Ag₂S-ZnO/GO nanocomposite with its enhanced photocatalytic and biological applications

Progression in nanotechnology enormously influence on the synthesis of highly proficient photo materials, which can be used for a number of applications in diverse fields. Herein, a novel heterostructured Ag₂S-ZnO/GO nanocomposite was fabricated via a simple sol-gel/ultrasound method and was used to study photocatalytic degradation of organic dye solution under UV/visible light irradiation. The physicochemical characteristics of prepared nanocomposite signify that it exhibits remarkable morphology, high surface area and homogenized particle distribution. The average crystallite size of ZnO, Ag₂S-ZnO and Ag₂S-ZnO/GO was calculated to be 21.2, 24.5 and 26.4 nm, respectively. Prepared nanocomposite are found to be exceptionally efficient for photocatalytic degradation of methyl orange (MO) as compared to other materials. The photodegradation of MO was achieved up to 98.1% under UV and 66.8% under visible light irradiation within 50 min. However, the characteristic features of graphene including storage and transferring of electrons and establishment of heterojunction between Ag₂S and ZnO are responsible for enhanced efficiency towards separation of photoinduced electron/hole pairs as well as increased charge transferring due to lowering of bandgap. More importantly, the Ag₂S-ZnO/GO nanocomposite displays superior antibacterial, antifungal and antioxidant activities. The further investigations of antibacterial and antifungal properties of as-synthesized nanocomposite revealed that by adding Ag₂S-ZnO/GO to bacterial and fungal media, a clear zone of inhibition for both bacteria and fungi medium was observed. It can be concluded from the results that Ag₂S-ZnO/GO nanocomposite having remarkable structure reliability are excellent candidate for both photocatalytic and biomedical applications. Moreover, the possible degradation mechanism of photocatalyst was also predicted.