Due to the unique structures, photoelectric properties, good catalytic activity, and broad potential applications, gold nanoclusters (Au ${}_n$ ) received extensive attention in catalysis, bioengineering, environmental engineering, and so on. In the present work, the structures and properties of Au ${}_n$ adsorbed on the MgO(001) and TiO ${}_2$ (101) surfaces were investigated by density functional theory. The results showed that the catalytic properties of Au ${}_n$ will be enhanced when Au ${}_n$ is adsorbed on certain supports. Because the difference of the outer electronic structure of metals in supports, the direction of the charge transfer was different, thus inducing the different charge distribution on Au ${}_n$ . When Au ${}_n$ was adsorbed on MgO(001) [TiO ${}_2$ (101)] surface, Au ${}_n$ will have negative [positive] charges and thus higher catalytic activity in oxidation [reduction] reaction. The variation of surface charges caused by the support makes Au ${}_n$ possess different catalytic activity in different systems. Moreover, the electronic structure of the support will make an obvious influence on the s and d density of states of Au ${}_n$ , which should be the intrinsic reason that induces the variations of its structure and properties. These results should be an important theoretical reference for designing Au ${}_n$ as the photocatalyst applied to the different oxidation and reduction reactions.

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.

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.