Facile preparation of surfactant or support material free CdS nanoparticles with enhanced photocatalytic activity

Abstract

Herein, we have described the production of CdS nanoparticles that are free from organic surfactant molecules or support material and an efficient photocatalytic activity of CdS nanoparticles having free surfaces for the reduction of toxic Cr(VI) to Cr(III). These template free CdS nanoparticles were synthesized by adopting the solution phase hexamethyldisilazane (HMDS)-assisted chemical synthetic method using CdCl2 and thiourea as the precursors. The nanoparticles were characterized by powder X-ray diffraction (PXRD), field emission-scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). As-prepared CdS nanoparticles exhibited an excellent photocatalytic performance for the reduction of Cr(VI) to Cr(III) at acidic pH under visible light illumination. The enhanced catalytic activity of CdS nanoparticles was explained by the availability of clean surfaces that are created by the absence of insulating organic molecules as a surfactant or stabilizing agent. This situation encouraged the efficient separation of photoexcited electron-hole pairs, which reflected as a stable transient photocurrent response during transient studies. Separation of electron-hole pairs was supported further by the observation of less resistance to the interfacial charges in the electrochemical impedance spectra (EIS). Since the catalyst also showed good photocatalytic stability and reusability, it can be an excellent candidate for treating wastewater.