关键词: 氧化钨/
氧化银/
光催化/
半导体异质结构
English Abstract
Photocatalytic activity of tungsten trioxide/silver oxide composite under visible light irradiation for methylene blue degradation
Shao Zi-Qiao,Bi Heng-Chang,
Xie Xiao,
Wan Neng,
Sun Li-Tao
1.FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing 210096, China
Fund Project:Project supported by the National Science Fund for Distinguished Young Scholars of China (Grant No. 11525415), the National Key R&D Program of China (Grant No. 2016YFA0501602), the National Natural Science Foundation of China (Grant No. 11674053), the Funds for International Cooperation and Exchange of the National Natural Science Foundation of China (Grant No. 51420105003), and the China Postdoctoral Science Foundation (Grant No. 2017M611653).Received Date:11 April 2018
Accepted Date:19 May 2018
Published Online:20 August 2019
Abstract:Dye pollution,one of the most serious problems in water pollution,has attracted the attention of scientists.There are many methods,such as chemical oxidation,physical adsorption,biodegradation,photocatalysis,etc.,that have been adopted to handle the crisis of dye polultion. Compared with other strategies,photocatalysis has its unique advantages including low energy consumption,environment amicableness and high efficiency.Tungsten trioxide (WO3),a semiconductor with a band gap of 2.8 eV,has unique physical and chemical properties,and it has been applied to the area of photocatalysis to solve the problem of water pollution in recent years.However,the photocatalytic efficiency of bulk tungsten oxide fails to reach the expected.In this paper,a one-dimensional complex of tungstun trioxide and silver oxide (WO3/Ag2O) is synthesized via a simple hydrothermal method for photocatalytic degradation of methylene blue.The crystal structure,morphology and photocatalytic degradation ability towards methylene blue are characterized and analyzed via X-ray diffraction,scanning electron microscopy,transmission electron microscope,X-ray photoelectron spectroscopy,and UV-Vis spectrophotometer.Silver oxide (Ag2O),with a band gap of 1.2 eV,is found to be sensitive to visible light.The combination of tungsten trioxide and silver oxide promotes its photocatalytic efficiency dramatically under visible light illumination. Results show that WO3 nanorods in the composite possess a one-dimensional,hexagonal structure with an average length of 4μm and a diameter of 200 nm.The Ag2O attached to WO3 nanorods forms hexagonal nanoparticles and their average diameter reaches 20 nm.It is observed that WO3/Ag2O composite displays a loose structure and a high specific surface area,which provides more reactive sites.Comparing with single component,UV-Vis spectrophotometry shows that the composite has a highabsorbance in the range of visible light.The combination of tungsten trioxide and silver oxide can change the band gap of the photocatalyst whereas the photocatalytic efficiency of the composite reaches 98% in 60 min under visible light.Therefore,the synergistic effect of WO3 and Ag2O plays a vital role in enhancing the photocatalytic performance.Moreover,the stability of photocatalyst is one of the most important indicators of its recycling and long-term effectiveness,and the present WO3/Ag2O composite has good catalytic and chemical stability.This investigation proves that the combination of wide bandgap photocatalysts with visible-light sensitive metal oxide with large specific area will improve photocatalytic activity efficiently under visible light.
Keywords: tungsten oxide/
silver oxide/
photocatalytic/
semiconductor heterostructure
