Preparation of AgBr decorated ZnO/ZnS nanocomposite for photocatalytic and antibacterial applications

Abstract

The first synthesis of AgBr decorated ZnO/ZnS heterostructure for powerful photocatalytic and antibacterial purposes is reported. The analytical results showed that the introduction of AgBr into the ZnO/ZnS matrix resulted in an increase in the specific surface area and a decrease in the optical energy gap of the sample. Moreover, various reactive species such as •O2−, •OH, Ag°, Br°, photogenerated holes and electrons were formed on the surface of the ZnO/ZnS/AgBr nanocomposites upon exposure to light. These factors played a crucial role in enhancing electron-hole pair separation and improving the photocatalytic efficiency and antibacterial activity of the material. The nanocomposites were investigated for photocatalytic degradation of synthetic dye solution under UVA-visible light irradiation. The results showed that the superior first-order kinetic rate constants (kapp) for the degradation of methylene blue and methyl orange of the as-prepared ternary composite under UVA irradiation were significantly improved to 0.109 and 0.030 min−1, respectively; which was more than twice the values of the sample without AgBr addition. Moreover, the results of inhibition of Gram-positive and Gram-negative bacteria on cotton fabric substrate showed that both the ZnO/ZnS and ZnO/ZnS/AgBr nanocomposites exhibited excellent antimicrobial efficacy of more than 99.95% under natural light.