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Phase diagram of Ti 8 O n in oxygen atmosphere. The spin distribution (spin up:yellow; spin down:l ight blue) of the corresponding clusters is shown in the phase diagram.
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Using the evolutionary algorithm USPEX and DFT+U calculations, we predicted a high‐symmetry geometric structure of the bare Ti8O12 cluster composed of 8 Ti atoms forming a cube, in which O atoms are at midpoints of all of its edges, in excellent agreement with experimental results. Using natural bond orbital analysis, adaptive natural density parti...
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... hase diagram as af unction of temperature and partial oxygen pressure is shown in Figure 2; it is clear that Ti 8 O 12 has aw ide stability field. Spin density distribution for stable Ti 8 O n (n = 10, 12, 13, 14, 16) clusters is also shown in Figure 2. ...
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... hase diagram as af unction of temperature and partial oxygen pressure is shown in Figure 2; it is clear that Ti 8 O 12 has aw ide stability field. Spin density distribution for stable Ti 8 O n (n = 10, 12, 13, 14, 16) clusters is also shown in Figure 2. Then, the second energy difference was used to determine stable clusters of Ti 8 O n ;itisd efined as: ...
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... the stepwise oxygen binding energy (Figure 3), we see that the binding of up to sixteen oxygen atoms on the Ti 8 cluster is particularly favorable thermodynamically,a nd the averaged oxygen binding energy shows that binding of all eighteen oxygen atoms to the Ti 8 cluster is still thermodynamically feasible. 12 (on which we focus here) also has ah ighly symmetric atomic structure (O h symmetry), in contrast to all other Ti 8 O n (n = 1-18) clusters with lower point group symmetries (Supporting Information, Figure S2). Ti 8 O 12 complexes play an important role in crystallization of ...
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... For instance, using the USPEX, a high-symmetry geometric structure of Ti8O12 cluster was predicted which was in excellent agreement with experimental results. [49] Mikhailova et al. predicted the ground state structures of CunAum nanoclusters (n + m ≤ 15) using the USPEX and DFT calculations and proposed that Cu7Au6 cluster is an excellent catalyst for CO oxidation. [50] By USPEX, a stable and ferromagnetic Fe17O10cluster with an accordion-like structure was predicted, which well explains the prominent mass abundance of Fe17O10in the experiment. ...
Clusters, an aggregation of several to thousands of atoms, molecules, or ions, are the building blocks of novel functional materials by atomic manufacturing and exhibit excellent applications in catalysis, quantum information, and nanomedicine. The evolution of cluster structures has been studied for many years. Many effective structural search methods, such as genetic algorithm, basin‐hopping, and so on, have been developed. However, the efficient execution of these methods relies on precise energy calculators, such as density functional theory (DFT) calculations. Up to now, limited by computational methods and capabilities, the researches mainly focus on free‐standing clusters, which are different from clusters in practical applications. Recently, the rapid development of big data‐driven machine learning is expected to replace DFT for high‐precision large‐scale computing. In this review, the present cluster search methods and challenges currently faced have been summarized. It is proposed that the development of artificial intelligence has the potential to solve some practical problems including the structural and properties evolution of clusters in complex environment, causing revolutionary developments in the fields of catalysis, quantum information, and nanomedicine based on clusters.
... [51][52][53], cubic Fe 13 O 8 and cage Fe 12 O 12 clusters [54][55][56][57][58][59][60][61] . However, the antiferromagnetic states were often found to be much more stable than the ferromagnetic counterparts 61,62 . There seems an incompatible contradiction for iron oxide clusters to bear high stability and strong ferromagnetism. ...
Isolated clusters are ideal systems for tailoring molecule-based magnets and investigating the evolution of magnetic order from microscopic to macroscopic regime. We have prepared pure Fen– (n = 7-31) clusters and observed their gas-collisional reactions with oxygen in a flow tube reactor. Interestingly, only the larger Fen– (n ≥ 15) clusters support the observation of O2-intake, while the smaller clusters Fen– (n = 7-14) are nearly nonreactive. What is more interesting is that Fe17O10– shows up with prominent abundance in the mass spectra indicative of its distinct inertness. In combination with DFT calculations, we unveil the stability of Fe17O10– within an interesting acordion-like structure and elucidate the spin accommodation in such a strongly ferromagnetic iron cluster oxide.
Due to challenges in preparing pure metal clusters and in controlling reactions, the oxides produced by metal clusters reacting with oxygen are often different from traditional ion-molecule products in the gas phase and their reactivity pattern is also largely unveiled yet. In this work, utilizing a customized Re-TOFMS having a home-made cluster source and a flow tube reactor, we have observed the gaseous reactions of Nin± clusters with oxygen and found magic clusters of Ni13O8± that dominate the mass distributions. By quantum chemistry calculations, we find that both Ni13O8− and Ni13O8+ clusters bear a regular cubic structure with 8 oxygen anchoring the eight angles, however, they have rather different spin accommodations. The Ni13O8− clusters have 15 unpaired spin-up electrons exhibiting cubic aromaticity and decent ferromagnetism, while the Ni13O8+ clusters take a lower-spin ground state (11 unpaired electrons), with spin-down population on the central Ni atom pertaining to ferrimagnetism. This is a class of metalloxocube clusters that hold properties of aromaticity and ferromagnetism/ferrimagnetism charcterized by a few spin electrons, which embodies the bonding nature of superatomic compounds and enables to develop cluster-genetic materials of multi-functionality.
Due to the merits of visible-light absorption and high conductivity, Ti³⁺ is a main focus among the modifications of TiO2. However, surface Ti³⁺ is unstable. Herein, surface-stable Ti³⁺ in an N-doped rGO-coated TiO2 nanotube sample is prepared. The N-doping introduced Ti-C bonds and an abundance of surface Ti³⁺, which produced several mid-gap states. These properties allow the composite to absorb nearly the full visible-light spectrum. Owing to the advantages of a broad visible-light absorption, short diffusion distance in the nanotube, and a good heterojunction, the composite exhibits a good photocatalytic activity. Under visible light and without Pt as a cocatalyst, methylene blue was degraded within 40 mins, and the H2 production rate is as high as 720 µmol g⁻¹ h⁻¹. Due to the synergistic effect of N doping and Ti-C bond formation, the configuration of surface Ti³⁺ is stabilized by a charge-transfer resonance mechanism. The tightly coated graphene also plays a vital role in protecting the surface Ti³⁺. Even after storage for one year, the photocatalytic activity and the EPR signal intensity from Ti³⁺ paramagnetic states remain unchanged within experimental error. It suggests that the surface Ti³⁺ concentration, and the properties of the composite are stable with time.
