摘要
二维材料因其独特的物理性质在光催化领域备受关注,通过构建异质结是提高二维材料光催化性能的有效策略。基于密度泛函理论,采用第一性原理方法系统研究了g-C_(6)N_(6)/GaTe范德华异质结的光催化性质。计算结果表明:g-C_(6)N_(6)/GaTe的晶格失配率为0.6%,形成能为−486 eV,异质结构稳定;异质结是带隙值为1.45 eV的间接带隙材料,形成稳定的能带交错排列,价带和导带的能带偏置分别为0.56和1.54 eV,同时在界面处生成由g-C_(6)N_(6)指向GaTe的内置电场,构成典型的Ⅱ型异质结构。在内置电场和带偏作用下,有利于光生电子-空穴对的有效分离,提高异质结的光催化性能。异质结在可见光范围内的光吸收系数高达约7×104 cm^(−1),制氢转换效率为16.48%,有利于光解水反应。最后,尝试对异质结施加载荷,在拉伸应力作用下异质结有明显的红移显现。g-C_(6)N_(6)/GaTe异质结是一种具有应用前景的光催化剂,该研究结果为g-C_(6)N_(6)/GaTe异质结的设计和制备提供了理论基础。
Two-dimensional materials have attracted much attention in the field of photocatalysis due to their unique physical properties,and constructing heterojunctions is an effective strategy to improve the photocatalytic performance of two-dimensional materials.The photocatalytic properties of g-C_(6)N_(6)/GaTe van der Waals heterojunctions have been systematically investigated based on density functional theory.The calculated results show that the lattice mismatch ratio of g-C_(6)N_(6)/GaTe is 0.6%,the formation energy is−486 eV and the heterostructure is stable.The heterojunction is an indirect band gap material with a band gap value of 1.45 eV,forming a stable interlaced arrangement of energy bands with an energy band bias of 0.56 eV and 1.54 eV in the valence and conduction bands,respectively.The built-in electric field pointing to GaTe constitutes a typical type Ⅱ heterostructure.Under the action of the built-in electric field and band polarization,it is conducive to the effective separation of photogenerated electron-hole pairs and improves the photocatalytic performance of the heterojunction.The light absorption coefficient of the heterojunction in the visible light range is as high as 7×104 cm^(−1),and conversion efficiency of the hydrogen production is 16.48%,which is favorable for the photolysis of water.Finally,an attempt was made to apply a load to the heterojunction,the heterojunction shows a clear red shift under tensile stress.g-C_(6)N_(6)/GaTe Heterojunction is a promising photocatalyst,and the results of this study provide a theoretical basis for the design and preparation of g-C_(6)N_(6)/GaTe heterojunction.
作者
董洪阳
任山令
黄欣
杨志红
王允辉
DONG Hongyang;REN Shanling;HUANG Xin;YANG Zhihong;WANG Yunhui(School of Electronic and Optical Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;Information Physics Research Center,School of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;New Energy Engineering Technology Laboratory of Jiangsu Province,Nanjing 210023,China)
出处
《材料研究与应用》
CAS
2022年第4期584-591,共8页
Materials Research and Application
关键词
Ⅱ型异质结
第一性原理
光催化
电子结构
type Ⅱ heterojunctions
first principles
photocatalysis
electronic structure
