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采用电负性原理,构建合理的红外光谱模型,对TiO_2红外光谱的振动频率与元素电负性之间的各种经验关系进行探究。采用溶胶-凝胶法制备(Fe,N)共掺杂TiO_2,利用X-射线衍射(XRD)、傅里叶红外光谱(FTIR)对样品的物相和红外光谱进行了表征。XRD物相分析表明当煅烧温度为600℃时,TiO_2样品中的无定形结构己基本转化为锐钛矿型结构。随着煅烧温度升高,TiO_2的X射线衍射峰逐渐由宽变窄,衍射强度由弱变强。当煅烧温度为700℃时,锐钛矿型的衍射峰基本消失,取而代之的是金红石相的衍射峰,但TiO_2的主晶相并没有发生改变。红外光谱分析表明(Fe,N)共掺杂TiO_2在650~500cm-1区间有一个较宽的吸收峰。电负性模拟计算了(Fe,N)共掺杂TiO_2红外光谱的伸缩振动频率,获得了Fe、N掺杂的位置、分子结构和键价特征:首先计算出约化质量μ,然后按照经典力学伸缩力常数k与频率ν之间满足的关系,结合力常数与电负性关系、键级的计算方法,计算了基本单元都是氧八面体的掺杂金红石、锐钛矿TiO_2的分子振动频率。结果表明:通过电负性理论计算的(Fe,N)共掺杂的TiO_2的红外光谱与实验测量的红外光谱的伸缩振动频率比较吻合。
Based on the principle of electronegativity, a reasonable model of infrared spectroscopy was constructed, and the empirical relationship between the vibration frequency of TiO_2 and the electronegativity of elements was explored. The (Fe, N) co-doped TiO 2 was prepared by sol-gel method. The phase and the infrared spectra of the samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) XRD phase analysis shows that the amorphous structure in TiO 2 has been transformed into anatase structure at 600 ℃. With the calcination temperature increasing, the X-ray diffraction peak of TiO_2 gradually narrowed from wide to narrow, and the diffraction intensity changed from weak to strong. When the calcination temperature is 700 ℃, the diffraction peaks of anatase disappear completely, and the diffraction peak of rutile phase is replaced by the diffraction peak of rutile phase. However, the main crystalline phase of TiO 2 has not changed. Infrared spectrum analysis shows that (Fe, N) co-doped TiO 2 has a broad absorption peak in the region of 650 ~ 500 cm -1. The electronegativity simulation was used to calculate the stretching vibration frequency of (Fe, N) co-doped TiO_2 infrared spectra. The position, molecular structure and bond price characteristics of Fe and N doping were obtained. First, the reduced mass μ was calculated, The relationship between the mechanical constant k and the frequency ν, the relationship between the force constant and the electronegativity, the bond-level calculation method, the molecular vibrations of anatase TiO_2 doped with anatase TiO_2 frequency. The results show that the infrared spectra of (Fe, N) co-doped TiO 2 calculated by the electronegativity theory are in good agreement with the experimental ones.