| Cite this article as: Tu Chun-Yun,Huang Wei-Jiang,Wang Kui. Theoretical study of the geometric structures and spectral properties of completely protonated clusters of Keggin-type hetero-niobium phosphomolybdic polyanions (Hn+3[PMo12-nNbnO40], n=1-4) [J]. J. At. Mol. Phys.(原子与分子物理学报), 2026, 43: 052002 (in Chinese) |
| Theoretical study of the geometric structures and spectral properties of completely protonated clusters of Keggin-type hetero-niobium phosphomolybdic polyanions (Hn+3[PMo12-nNbnO40], n=1-4) |
| Hits 193 Download times 3 Received:February 20, 2025 Revised:May 23, 2025 |
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| DOI
10.19855/j.1000-0364.2026.052002 |
| Key Words
Keggin-type Heteropolyanions Protonated Structure Spectroscopic Property Density Functional Theory Genetic Algorithm |
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| Abstract
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| Keggin-type heteropoly acids play an important role in the field of energy catalytic conversion as efficient photocatalysts. Although it is easy to realize photocatalytic reactions by using them experimentally, it is still difficult to study the related photocatalytic reaction mechanism in detail at the atomic level, in which it is very important to obtain a relatively reasonable catalyst cluster model. In this paper, the stable geometric structures and spectral properties of Keggin-type hetero-niobium polyanions completely protonated cluster (Hn+3[PMo12-nNbnO40], n=1-4) have been investigated by using a self-developed genetic algorithm program combined with density functional theory. By observing the effect of niobium-heteroatom substitution molybdenum at the surface of clusters and occupation of protons on the geometric structures and spectral properties of the systems, we expect to provide useful information for the molecular design of photocatalyst based on these clusters and the investigation of photocatalytic reaction mechanism. Based on the calculated data, we find: in the optimized cluster geometries, with the increase of the number of Nb-heteroatoms, their distribution on the cluster skeleton can exhibit a certain rule (tends to be discrete distribution or to form an equilateral triangle via shared O-bridges), and protons tend to form a single bond with the terminal-O associated with Nb-heteroatoms (or its neighbors). The dipole moment of cluster systems starts from the maximum value to the lowest value and then increases gradually. This can be attributed to the relatively small electronegativity difference between the Nb-heteroatom and the substituted Mo atom, as well as the difference in the substitution position patterns. The Infrared (or Raman) absorption of the studied systems are mainly distributed in two wavenumber intervals (0-1500 cm-1) and (3600-4000 cm-1). The former corresponds to the vibration modes between heavy atoms (bridge-O-Mo, O-Nb, etc.) or the related local cluster skeletons, while the latter corresponds to the vibration modes of the O-H single bonds of the terminal groups. At the same time, they exhibit distinguishable Infrared absorption distribution in the 1200-1500 cm-1 wavenumber interval, and can show intensity difference for Raman absorption in the high wavenumber interval. |
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