Ag/AgBr coupled low crystalline Nb 2 O 5 as an effective photocatalyst for the degradation of rhodamine B
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Ag/AgBr coupled low crystalline Nb2O5 as an effective photocatalyst for the degradation of rhodamine B Peng Zhang1,2 , Xiaojuan Jian3, Jianhong Tan4,a), Yuanming Ran1, Guoqing Zhang4 1
College of Materials Science and Engineering, Yangtze Normal University, Chongqing 408100, China Helmholtz-Zentrum Berlin for Materials and Energy, Institute of Applied Materials, Berlin 14109, Germany 3 College of Materials Science and Engineering, University of Science & Technology Beijing, Beijing 100083, China 4 College of Chemistry and Chemical Engineering, Yangtze Normal University, Chongqing 408100, China a) Address all correspondence to this author. e-mail: [email protected] 2
Received: 20 March 2020; accepted: 15 May 2020
A novel Ag/AgBr/Nb2O5 heterojunction photocatalyst was successfully developed via a facile solvothermal method combined with deposition–precipitation. The morphology and composition of the Ag/AgBr/Nb2O5 photocatalyst were investigated by transmission electron microscopy and X-ray energy-dispersive spectrometry, respectively. The results showed that metallic Ag was formed on the surface of the AgBr by an in situ photoreaction. The low crystalline Nb2O5 (L-Nb2O5) substrate provides the photocatalyst with a high specific area and numerous active sites for catalysis, while the combination of the Ag/AgBr with L-Nb2O5 effectively facilitates the separation of photo-generated charge carriers. The photocatalytic activities of the samples were measured using the degradation of an aqueous solution of rhodamine B under different LEDs with UV (365 nm), yellow (595 nm), and white (400 nm ≤ λ ≤ 800 nm) light. The Ag/AgBr/L-Nb2O5 photocatalyst displayed a much higher photocatalytic activity than bare L-Nb2O5 under UV and visible-light irradiation.
INTRODUCTION Nb2O5, a typical n-type transition metal oxide, exists in several crystal polymorphs depending on the heating temperature and the synthesis procedures, including the most common pseudo-hexagonal (TT-Nb2O5) phase and the orthorhombic (T-Nb2O5) phase [1]. Significant efforts have been devoted to adjusting its crystal structures [2] and morphology [3, 4, 5] to improve its performance in certain fields, such as energy storage and photocatalysis. In addition to solid-state synthesis, Nb2O5 is commonly synthesized using a solvothermal method [6, 7]. However, the synthesis is usually performed at a relatively high temperature, and it is difficult to control the synthesis to obtain Nb2O5 with a specific crystalline structure. In our previous study [7], L-Nb2O5 was successfully prepared via a facile solvothermal method at a relatively low temperature. L-Nb2O5 has the advantages of a large surface area and ultrafine particle size, which are responsible for its stable visiblelight photocatalytic activity. Due to its band gap, which is similar to that of resting TiO2, in a relatively wide range from about 2.8 to 3.8 eV [8, 9, 10], Nb2O5 has attracted increasing attention for its potential utility in photocatalysis, especially for the photocatalytic degradation of organ
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