二维层状WS_(2)/ZnO范德华异质结光催化剂的设计与理论研究  

Design and Theoretical Study of Two-Dimensional Layered WS_(2)/ZnO Van der Waals Heterostructure Photocatalyst

作　　者：赵婷婷 姚曼[1,2] 王旭东[1,2] ZHAO Tingting;YAO Man;WANG Xudong(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,China;Key Laboratory of Solidification Control and Digital Preparation Technology,Dalian University of Technology,Dalian 116024,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024 [2]大连理工大学/凝固控制与数字化制备技术重点实验室,辽宁大连116024

出　　处：《材料研究与应用》2023年第2期205-212,共8页Materials Research and Application

基　　金：国家自然科学基金项目(21233010)。

摘　　要：范德华异质结(vdWH)的构建是一种提高二维材料性能的有效途径,借助第一性原理计算方法系统地研究了WS_(2)/ZnO vdWH的晶体结构及其电子、光催化和光学性质。计算结果表明,二维WS_(2)/ZnO vdWH具有II型能带排列特征,能有效分离光生载流子,提升载流子分离效率。由于电子会自发从WS_(2)转移到ZnO单层,WS_(2)/ZnO vdWH层间会形成内建电场,有效抑制光激发载流子的复合。与WS_(2)和ZnO两个单层相比,WS_(2)/ZnO vdWH的光学吸收系数在可见光区明显提高,数量级可达104 cm-1,具有增强的太阳能利用效率。通过能带排列计算发现,酸性条件比中性或碱性条件更利于WS_(2)/ZnO vdWH的光催化水解反应。此外,还探究了机械应变对WS_(2)/ZnO vdWH电子和光催化性质的影响规律,发现施加双轴拉伸应变可以调控WS_(2)/ZnO vdWH的II型异质结转变为I型异质结,有望应用于光电器件领域。上述结果表明,WS_(2)/ZnO vdWH是一种极具应用潜力的分解水光催化剂,计算结果可以为WS_(2)/ZnO vdWH的设计和制备提供理论指导和科学依据。The construction of van der Waals heterostructure(vdWH)is an effective channel to improve the performance of two-dimensional materials.In this paper,the crystal structure of WS_(2)/ZnO vdWH and its electronic,photocatalytic,and optical properties are systematically investigated based on the first-principles calculation.The calculation results show that the two-dimensional WS_(2)/ZnO vdWH possesses type-Ⅱband alignment,which can effectively separate photogenerated carriers and improve carrier separation efficiency.Due to the spontaneous transfer of electrons from WS_(2) to the ZnO monolayer,a built-in electric field will be formed between the WS_(2)/ZnO vdWH layers,which can effectively inhibit photoexcited carrier recombination.Compared with the two monolayers of WS_(2) and ZnO,the optical absorption coefficient of WS_(2)/ZnO vdWH is significantly improved in the visible light range,with an order of magnitude of 104 cm-1,showing that the heterostructure has enhanced solar energy utilization efficiency.According to the energy band alignment calculation,the acidic condition is more favorable for the photocatalytic hydrolysis of WS_(2)/ZnO vdWH than neutral or alkaline conditions.Additionally,the effect of mechanical strain on the electronic and photocatalytic properties of WS_(2)/ZnO vdWH is also explored.It is found that the application of biaxial tensile strain can regulate the transformation of type II heterojunction of WS_(2)/ZnO vdWH into type I heterojunction,which is expected to be applied in the field of optoelectronic devices.The above results show that WS_(2)/ZnO vdWH is a photocatalyst with great application potential for water splitting.The calculation results in this paper can provide theoretical guidance and a scientific basis for the design and preparation of WS_(2)/ZnO vdWH.

关 键 词：二维材料 范德华异质结 第一性原理 光催化 分解水 

分 类 号：TB34[一般工业技术—材料科学与工程] O469[理学—凝聚态物理]