Fabrication of CdS/Ag/LPTNSs heterojunctions for visible light driven photocatalytic degradation of organic pollutant

Abstract

Ternary CdS/Ag/LPTNSs heterojunctions were prepared by a two-step method. The prepared photocatalysts were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), specific surface area analyzer (BET), photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) measurement. The results showed that the prepared LPTNSs had lamellar multilayer structure and uniformly distributed silver particles and CdS on their surface. The PEC and PL results show that the formation of ternary heterojunction structure can improve the efficiency of photogenerated electron and hole separation. Under visible light irradiation, the photodegradation of methylene blue (MB) in the presence of various photocatalysts showed that photocatalytic performance of CdS/Ag/LPTNSs was better than that of P25, LPTNSs, CdS, Ag/LPTNSs and CdS/LPTNSs. A maximum removal efficiency of MB reached 84% within 90 min over CdS/Ag/LPTNSs. Moreover, the kinetic constant of CdS/Ag/LPTNSs is 11.8, 10.4, 4.3, 2.4 and 1.7 times as much as that of P25, LPTNSs, CdS, Ag/LPTNSs and CdS/LPTNSs, respectively. In addition, the repeated photodegradation study showed that CdS/Ag/LPTNSs exhibited good stability, and the removal rate still reached 83% after 4 cycles. This work provides a simple and low-cost method for the synthesis of ternary CdS/Ag/LPTNSs nanocomposite to photocatalytic degradation of organic pollution.