Anchoring Plasmonic Ag@AgCl Nanocrystals onto ZnCo2O4 Microspheres with Enhanced Visible Photocatalytic Activity

Abstract

Abstract In this work, a comprehensive investigation of the composite Ag@AgCl/ZnCo2O4 microspheres photocatalyst, prepared by a facile two-step method, is presented, and using complementary characterization tools such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X ray spectroscopy (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), UV-Vis diffuse reflectance spectroscopy (DRS), and Brunauer-Emmett-Teller (BET). Results show that the composite Ag@AgCl/ZnCo2O4 photocatalyst has good microspheres morphology and high crystalline and its absorption intensity in the whole spectrum range is higher than that of pure ZnCo2O4. It is observed that the specific surface area of the composite Ag@AgCl/ZnCo2O4 photocatalyst and the adsorption efficiency of rhodamine B (RhB) increase as a result of deposition of Ag@AgCl. In the Ag@AgCl/ZnCo2O4 degradation system of RhB, the photocatalytic degradation rate of 0.2Ag@AgCl/ZnCo2O4 becomes 99.4% within 120 min, and RhB is almost completely degraded. The reaction rate constant of composite 0.2Ag@AgCl/ZnCo2O4 photocatalyst is found to be 0.01063 min−1, which is 1.6 times that of Ag@AgCl and 10 times of the minimum value of ZnCo2O4. In addition, the radical capture experiment indicates that, in the reaction system of Ag@AgCl/ZnCo2O4, the main oxidative species of Ag@AgCl/ZnCo2O4 photocatalyst are superoxide anion (O· − 2 − 2) and hole (h+) and not hydroxyl radical (·OH). Based on the results, a Z-scheme plasmon photocatalytic mechanism of Ag@AgCl/ZnCo2O4 composite system is proposed, to elucidate the RhB degradation.

Keywords

• Composite
• Microspheres
• Plasmonic
• Photocatalytic degradation