Construction of 2D-2D TiO_2 nanosheet/layered WS_2 heterojunctions with enhanced visible-light-responsive photocatalytic activity  

构建2D-2D TiO_2纳米片/层状WS_2异质结用以增强可见光响应光催化活性（英文）

作　　者：Yongchuan Wu Zhongmin liu Yaru Li Jitao Chen Xixi Zhu Ping Na 吴勇川;刘中敏;李亚茹;陈继涛;主曦曦;那平(天津大学化工学院,天津300350;德州大学化学与化学工程学院,山东德州253023;山东科技大学化学与环境工程学院,山东青岛266590)

机构地区：[1]School of Chemical Engineering and Technology,Tianjin University,Tianjin 300350,China [2]College of Chemistry and Chemical Engineering,Dezhou University,Dezhou 253023,Shandong,China [3]College of Chemistry and Environmental Engineering,Shandong University of Science and Technology,Qingdao 266590,Shandong,China

出　　处：《Chinese Journal of Catalysis》2019年第1期60-69,共10页催化学报（英文）

基　　金：supported by the National High Technology Research and Development Program of China(863 Program,2012AA063504);the National Natural Science Foundation of China(U1407116,21511130020,21276193);the Tianjin Municipal Natural Science Foundation(13JCZDJC35600)~~

摘　　要：Constructing nanocomposites that combine the advantages of composite materials,nanomaterials,and interfaces has been regarded as an important strategy to improve the photocatalytic activity of TiO2.In this study,2D‐2D TiO2 nanosheet/layered WS2(TNS/WS2)heterojunctions were prepared via a hydrothermal method.The structure and morphology of the photocatalysts were systematically characterized.Layered WS2(~4 layers)was wrapped on the surface of TiO2 nanosheets with a plate‐to‐plate stacked structure and connected with each other by W=O bonds.The as‐prepared TNS/WS2 heterojunctions showed higher photocatalytic activity for the degradation of RhB under visible‐light irradiation,than pristine TiO2 nanosheets and layered WS2.The improvement of photocatalytic activity was primarily attributed to enhanced charge separation efficiency,which originated from the perfect 2D‐2D nanointerfaces and intimate interfacial contacts between TiO2 nanosheets and layered WS2.Based on experimental results,a double‐transfer photocatalytic mechanism for the TNS/WS2 heterojunctions was proposed and discussed.This work provides new insights for synthesizing highly efficient and environmentally stable photocatalysts by engineering the surface heterojunctions.自Fujishima等首次报道以来, TiO_2作为一种重要的光催化剂引起了人们的广泛关注.迄今为止,研究人员已经开发出了各种形貌的具有不同晶型结构的TiO_2,并用于光催化降解有机污染物.然而, TiO_2的宽禁带(3.2 eV)使其难以被可见光激活,导致对太阳光的利用效率低下.而且,在光催化反应中,低的量子效率无法满足实际应用.因此,开发具有可见光响应的高催化活性的TiO_2基催化剂具有重要意义.集成复合材料、纳米材料和界面的优势构建纳米复合材料已成为提高TiO_2光催化活性的重要策略. WS_2具有典型的类石墨烯层状结构和窄的带隙(1.35 eV),且其导带高于TiO_2的导带,适合作为助催化剂修饰TiO_2,使其具备可见光响应光催化活性.本文采用一步水热法,以二维(2D)TiO_2纳米片作基质材料,直接在其表面原位生长WS_2层,制得了2D-2D TiO_2纳米片/层状WS_2(TNS/WS_2)异质结. XRD及Raman结果表明,层状WS_2与TiO_2纳米片紧密结合在一起,且两者之间形成了W=O键.TEM结果显示,层状WS_2以面-面堆叠方式均匀地包覆在TiO_2纳米片表面,包覆层数约为4层.光催化性能测试结果表明,可见光照射下, TNS/WS_2异质结对RhB的光催化降解能力高于原始TiO_2纳米片和层状WS_2,光催化活性得到明显增强.紫外可见光谱试验结果显示,层状WS_2的引入极大地增强了异质结的光吸收性能. PL光谱测试表明, TNS/WS_2异质结具有更高效的载流子分离效率.为了进一步证实是光吸收性能的提升还是载流子分离效率的增强对光催化性能提起其主要作用,本文还研究了3D-2D TiO_2空心微球/层状WS_2(THS/WS_2)复合材料.结果表明, TNS/WS_2异质结比THS/WS_2复合材料具有更高效的光生电子和空穴的分离能力.从而证明了TiO_2纳米片与层状WS_2之间完美的2D-2D纳米界面和紧密的界面结合,显著增加了载流子分离效率,因此光催化活性得到明显提高.为了研究TN

关 键 词：WS2 TiO2 NANOSHEET Heterojunction Photocatalysis Visible‐light responsive 

分 类 号：TQ426[化学工程] TB383.1[一般工业技术—材料科学与工程]