CAJ | 학술논문

采用基于密度泛函理论的平面波赝势方法,对Na_(0.2)TiO_2的能带结构、电子态密度和电荷密度进行了分析计算.结果表明,Na_(0.2)TiO_2属于一种间接带隙半导体,禁带宽度为2.81 eV;其电子态密度主要由Ti的3d层电子和O的2p层电子的能态密度决定;该材料对紫外线有较强的宽频吸收,拓展了光谱响应范围,提高太阳能利用转化率和光催化效率;Ti-O键比Na-O键结合的更紧密,Na原子与O原子形成的是离子性较强而共价键较弱的混合键,Ti-O键的共价作用要强于Na-O键.因此,可以通过阳离子交换来调变钛酸钠的键特性及稳定性.
채용기우밀도범함이론적평면파안세방법,대Na_(0.2)TiO_2적능대결구、전자태밀도화전하밀도진행료분석계산.결과표명,Na_(0.2)TiO_2속우일충간접대극반도체,금대관도위2.81 eV;기전자태밀도주요유Ti적3d층전자화O적2p층전자적능태밀도결정;해재료대자외선유교강적관빈흡수,탁전료광보향응범위,제고태양능이용전화솔화광최화효솔;Ti-O건비Na-O건결합적경긴밀,Na원자여O원자형성적시리자성교강이공개건교약적혼합건,Ti-O건적공개작용요강우Na-O건.인차,가이통과양리자교환래조변태산납적건특성급은정성.
The band gap,density of states,electron density of monoclinic Na_(0.2)TiO_2 were simulated by using the plane wave pseudo potentials (PWPP) based on the density functional theory (DFT).Calculated results show that Na_(0.2)TiO_2 is an indirect semiconductor with the band gap of 2.81 eV.The density of states is mainly made up of Ti 3d and O 2p.The material has strong broadband UV absorption,extends the range of spectral response and increases utilization rate of solar energy and photocatalytic efficiency.While the Na and O atoms is connected by a strong ionic and weak covalent mixed bond, the Ti-O bond is shorter and has more covlent component than Na-O bond.This work may provides a theoretical guid for the molecular design and applications of Na_(0.2)TiO_2 and related materials.Therefore,the bond characteristics and stability of sodium titanate can be changed by cation-exchange.