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Kai Yang School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China; and State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002, Fujian, China

Lihua Zhu, Wanqin Zhou, and Renyue Liu School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi, China (Received 5 May 2016; accepted 20 July 2016)

A series of Ag2S/Ag2WO4 composite microrods with different Ag2S contents (10–50 wt%) were synthesized via a facile successive precipitation route. The texture and optical properties of the pure Ag2S, Ag2WO4, and Ag2S/Ag2WO4 composites were intensively characterized by some physicochemical characterizations like N2 physical adsorption, x-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Ultraviolet–visible spectroscopy, x‐ray photoelectron spectroscopy, photoluminescence spectroscopy, and photocurrent measurements. Under visible light irradiation, different organic dyes, e.g., methylene blue and methyl orange dye were applied to evaluate the photocatalytic performances by their photocatalytic degradation reactions. The Ag2S/Ag2WO4 composite microrods exhibited superior photocatalytic activity and stability. The high crystallinity of Ag2WO4 and improved texture properties of Ag2S/Ag2WO4 resulted in their enhanced photocatalytic property. More importantly, the Ag2S/Ag2WO4 heterojunctions with matching electronic band structures obviously enhanced the separation of photo‐ generated electrons and holes, further promoting the photocatalytic reaction. I. INTRODUCTION

Currently, human being is confronted with the problems of energy shortage and environment pollution. How to deal with these problems is an important issue for the scientist. Photocatalysis technology has promising application prospect in environmental remediation and green energy production.1–9 Under light irradiation, photocatalysis can decompose most of the organic pollutants in water and air without selectivity, ideally producing CO2 and H2O as end products. Moreover, photocatalysts can effectively convert solar energy to chemical energy in the form of clean and renewable hydrogen fuel or solar fuels.10–12 In recent years, tungstate-based photocatalytic materials have attracted intensive attention due to their wide light range absorption.13–20 In numerous tungstates, Ag2WO4 possesses unique physical and chemical properties because of its special spatial structure and the characteristics of the spontaneous polarization. However, as photocatalyst,

Contributing Editor: Xiaobo Chen a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.284

Ag2WO4 can only absorb UV light due to its large band gap (;3.5 eV). Another problem for Ag2WO4 is its poor stability because under light illumination photocorrosion readily takes place over Ag-based semiconductors if no sacrificial reagent is present.21 Therefore, how to promote the photoca