Photoinhibition and photocatalytic response of surfactant mediated Pt/ZnO nanocomposite

Abstract

Water pollution and bacterial resistance are universal problems. Drugs and protocols have been employed to deal with involved microbes and pollutants but these customary chemicals have many limitations. It is essential to produce new methods and materials to deal with these deleterious microbes. In the present contribution, highly efficient and stable nanocomposite of platinum activated zinc oxide was synthesized by a new plant extract and surfactant assisted protocol. The cetylpyridinium chloride was applied as surfactant to obtain high dispersion of spherical ZnO. The platinum ions were reduced on the ZnO surface by the use of Rhazya stricta plant extract. The prepared nanomaterial was used for photoinactivation of multidrug resistant bacterium Escherichia coli (E. coli). The synthesized nanomaterial showed strong E. coli inhibition efficiency in the presence of light and the observed diameter of zone of inhibition was 21 ±0.4. The effect of light on the inhibition of E.coli was studied by measuring the activated oxygen radicals inside the bacterium cell. The surface morphology of E.coli before and after treatment with Pt/ZnO was studied by SEM. Such effect was not observed in dark. The toxicity of the synthesized nanomaterials was also studied through haemolytic activity and the result shows that the nanomaterial prepared by the said method has very low toxicity. The photocatalytic degradation of methylene blue (MB) was also investigated in the presence of the synthesized nanomaterials. Effect of different parameters such as concentration of Pt/ZnO, Irradiation time and dye concentrations were also studied. An incredible photocatalytic deprivation of MB (98 %) was observed for Pt/ZnO nanocomposite as compared to individual Pt (48%) and ZnO (71%) nanoparticles after 5 minutes of irradiations. Further research is required to investigate the applications of Pt/ZnO nanocomposite.