دانلود رایگان مقاله ساخت عمودی طرح-Z نوع WO3 فتوکاتالیست کامپوزیت Ag3PO4

Abstract

A direct Z-scheme type photocatalyst WO3/Ag3PO4 composite (molar ration 1:1, 1W/1Ag) was prepared by hydrothermal method. The 1W/1Ag was characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), UV–vis diffuse reflection spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence emission spectroscopy (PL) etc. technologies. The photocatalytic performances were evaluated by degradation of methylene blue (MB) and methyl orange (MO), and their removal rates were up to 95% after 60 min and 90% after 180 min, respectively. The prepared 1W/1Ag exhibits a much higher photocatalytic activity than pure Ag3PO4 and pure WO3 under visible light irradiation. The apparent rate constants of MB and MO degradation on 1W/1Ag are about 2.4 and 2.5 times that of pure Ag3PO4, respectively. The enhanced performance of the 1W/1Ag is attributed to a synergistic effect including relatively high surface area, strong light absorption, matched energy band structure, and the improved separation of photogenerated charge carriers between the two components. A reasonable Z-scheme mechanism referring to directed migration of photoinduced carriers was proposed. Thus, it can be suggested that the 1W/1Ag can serve as a promising photocatalyst for environmental purification and clean energy utilization.

4. Conclusions

In this work, a novel 1W/1Ag composite was successfully synthesized using hydrothermal method with two steps and employed in degrading two kinds of organic dye contaminant under visible light. Compared with pure Ag3PO4 and WO3, 1W/1Ag exhibited notably enhanced photocatalytic efficiency. The degradation of MB and MO obeyed the pseudo-first-order kinetics. The enhanced photocatalytic performance and stability were attributed to the direct Z-scheme heterojunction structure and synergic effect of Ag3PO4 and WO3, which could be benefit to efficient electron–hole separation and enhanced light energy conversion efficiency. Under visible light illumination, the photoexcited electrons in the conduction band of WO3 and retained holes in the valence band of Ag3PO4 are quickly combined. Meanwhile, the photogenerated holes in the valence band of WO3 played a major role in oxidation reactions. Undoubtedly, the developing of 1W/1Ag not only improves the reaction activity, but also effectively reduces the cost of the Ag3PO4 based photocatalyst, which would be a desired alternative as a simple, efficient, and promising photocatalyst material for wastewater remediation.