Qingzhen Han

At present, a large number of compounds of known structure lack basic physical property data and thermodynamic data. In order to promote data integrity and usability in chemistry database, the study calculates the structure of about 200,000 compounds using Gaussian03 software programs based on compounds structure data and compounds profiles. Meanwhile, the study performs geometric structure optimization, thermodynamic data analysis, and spectrum analysis. Then, compound species, together with their thermodynamic parameters and spectrum data, are extracted from quantum calculation results according to international standards, including infrared absorption spectrum, dipole moment, absolute polarizability, turning temperature and constant, zero-point vibrational energy, zero-point correction, molecular internal energy, molecular kinetic energy, enthalpy, free energy, heat capacity at constant volume, and entropy. A second processing (i.e., data analysis, mining and duplicate checking) results in quantum chemical calculation data of 18000 compounds (including spectrum data of 5321 compounds). To improve data reusability, all the resulted data have been standardized and processed for easier reuse.

Exploring new types of photocatalysts and modifying the photocatalytic activity have attracted more and more extensive attention in many research fields. Anatase TiO2, a promising photocatalyst widely studied, can only absorb the ultraviolet light and thus only make little use of the power in visible light. Therefore, it is an urgent task to make theoretical and experimental investigations on the photocatalytic mechanism in anatase TiO2 and then improve its visible light response so as to utilize more visible light. Now, in the present paper, we carry out a systematic theoretical investigation on modifying the photocatalytic properties of the anatase TiO2 (101) surface via doping transition metal neutral atoms such as Fe, Ni, Pd, Pt, Cu, Ag, and Au by using the plane wave ultrasoft pseudopotential method of the density functional theory. The dependence of the macroscopic catalytic activity on electronic structure and optoelectronic property is uncovered by making a comparative analysis of the geometric structures, the electronic structures, and the optical properties of the undoped and doped anatase TiO2 (101) surfaces. Our numerical results show that doping certain transition metals can suppress the band gap or induce extra impurity energy levels, which is beneficial to improving the visible light response of the TiO2 (101) surface in different ways. In most cases, the new impurity energy levels will appear in the original band gap, which comes from the contribution of the d electronic states in the transition metal atoms. Moreover, the photocatalytic activity of the TiO2 (101) surface can be changed differently by doping different transition metal atoms, which is closely dependent on the bandgap width, Fermi energy, the impurity energy level, and the electron configuration of the outermost shell of the dopants. This research should be an instructive reference for designing TiO2 (101) photocatalyst and improving its capability, and also helpful for understanding doping transition metal atoms in other materials.