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Thermoelectric research has made great progress in recent years, but large-scale applications of thermoelectric materials are still far from realisation. Finding ways to improve their thermoelectric performance remains an important challenge. In4Se3 stands out as a material with exceptional thermoelectric performance and notably low thermal conductivity. However, its ZT value is constrained by the power factor. We employed first principles calculations to assess the impact of stresses on the structural and electronic properties of In4Se3. Independent elastic constants, bulk modulus B, shear modulus G, and Young's modulus E all exhibit an increase with increasing stresses. The B/G value of In4Se3 increased from 1.75 at 0 GPa to 2.12 at 5 GPa, indicating that the toughness of the material gradually increased. The calculated phonon curves show that In4Se3 demonstrates mechanical stability under both tensile stress (−1 GPa) and compressive stress (1–5 GPa) conditions. The calculated electronic structure reveals that, with increasing compressive stresses, the band gap in the PBE potential decreases from 0.15 eV at 0 GPa to 0.01 eV at 5 GPa. Similarly, in the HSE06 potential, the band gap decreases from 1.00 eV at 0 GPa to 0.73 eV at 5 GPa. Thermoelectric transport parameters of the material are calculated by solving the semi classical Boltzmann transport equation. Increasing the compressive stresses can increase both the Seebeck coefficient and the conductivity. Consequently, the power factor of In4Se3 has been greatly improved. At 700 K, the power factor can be increased by 19% in the optimal carrier range. Therefore, this study offers a theoretically viable approach to enhance the thermoelectric performance of In4Se3. [ABSTRACT FROM AUTHOR]

Bulk cobalt does not react with water at room temperature, but cobalt nanometals could yield corrosion at ambient conditions. Insights into the cobalt cluster reactions with water and oxygen enable us to better understand the interface reactivity of such nanometals. Here we report a comprehensive study on the gas-phase reactions of Con±/0 clusters with water and oxygen. All these Con±/0 clusters were found to react with oxygen, but only anionic cobalt clusters give rise to water dissociation whereas the cationic and neutral ones are limited to water adsorption. We elucidate the influences of charge states, bonding modes and dehydrogenation mechanism of water on typical cobalt clusters. It is unveiled that the additional electron of anionic Con– clusters is not beneficial to H2O adsorption, but allows for thermodynamics- and kinetics-favourable H atom transfer and dehydrogenation reactions. Apart from the charge effect, size effect and spin effect play a subtle role in the reaction process. The synergy of multiple metal sites in Con– clusters reduces the energy barrier of the rate-limiting step enabling hydrogen release. This finding of water dissociation on cobalt clusters put forward new connotations on the activity series of metals, providing new insights into the corrosion mechanism of cobalt nanometals. Cobalt-based materials have a wide range of applications from information storage to electromagnetic absorbers in aerospace manufacturing, but the corrosion of cobalt nanosurfaces is poorly explored. Here, the authors combine mass spectrometry and DFT to study gas-phase reactions of Con±/0 (n = 1–30) with water and oxygen and find that only anionic cobalt clusters give rise to water dissociation, whereas the cationic and neutral ones are limited to water adsorption. [ABSTRACT FROM AUTHOR]

This study examines the chemical reactivity of niobium clusters with carbon dioxide (CO 2 ), with an emphasis on the analysis of the ensuing products Nb 4 O 6 + and Nb 3 O 6 - , which show up in the cationic and anionic mass spectra, respectively. Using density functional theory (DFT) calculations, we demonstrate the reactivity of the Nb n ± clusters with CO 2 and reveal distinct stabilization mechanisms for the two prominent products. The stability of Nb 3 O 6 - is determined by the existence of ten π bonds pertaining to π-electron delocalization, which conforms to the nxc π electron configuration model. Despite having only a one-atom distinction, Nb 4 O 6 + exhibits superatomic electron shells embodying superatom stability. The divergent stabilizing mechanisms found in Nb 4 O 6 + and Nb 3 O 6 - illustrate the intricate nature of cluster chemistry and the significance of electronic structure in governing cluster stability and reactivity.

Water is crucial for various physicochemical processes at the liquid-solid interfaces. In particular, the interfacial water, mediating the electric field and solvation effect along with the solid, corporately determine the electrochemical properties. Understanding the interaction between solid properties and the interface water holds significant importance in interfacial dynamics. However, the impact of alterations in the charged state of solid surfaces induced by contact electrification on interfacial water remains unknown. Here, the evolution of atomic-level resolution maps of hydration layers are reported on charged surfaces using 3D atomic force microscopy (3D-AFM). These findings demonstrate that electrostatic interactions can reinforce, distort, or collapse the characteristic structure of hydration layers. More importantly, these interactions exhibit interlayer differences and sample specificity in hydration layer structures of different substrates. In addition, similar oscillations of the hydration layer are observed at the electrochemical interface under different voltage biases. This suggests that contact-electrification has the potential to serve as a novel method for manipulating and regulating chemical reactions at the interface., (© 2024 Wiley‐VCH GmbH.)

The size dependence of metal cluster reactions frequently reveals valuable information on the mechanism of nanometal catalysis. Here, the reactivity of the Pt n + (n = 1-40) clusters with N 2 O is studied and a significant dependence on the size of these clusters is noticed. Interestingly, the small Pt n + clusters like Pt 3 + and Pt 4 + are inclined to form N 2 O complexes; some larger clusters, such as Pt 19 + , Pt 21 + , and Pt 23 + , appear to be unreactive; however, the others such as Pt 3 , 9,15 + and Pt 18 + are capable of decomposing N 2 O. While Pt 9 + rapidly reacts with N 2 O to form a stable quasitetrahedron Pt 9 O + product, Pt 18 + experiences a series of N 2 O decompositions to produce Pt 18 O 1-7 + . Utilizing high-precision theoretical calculations, it is shown how the atomic structures and active sites of Pt n + clusters play a vital role in determining their reactivity. Cooperative dual Lewis-acid sites (CDLAS) can be achieved on specific metal clusters like Pt 18 + , rendering accelerated N 2 O decomposition via both N- and O-bonding on the neighboring Pt atoms. The influence of CDLAS on the size-dependent reaction of Pt clusters with N 2 O is illustrated, offering insights into cluster catalysis in reactions that include the donation of electron pairs., (© 2024 Wiley‐VCH GmbH.)

Bulk cobalt does not react with water at room temperature, but cobalt nanometals could yield corrosion at ambient conditions. Insights into the cobalt cluster reactions with water and oxygen enable us to better understand the interface reactivity of such nanometals. Here we report a comprehensive study on the gas-phase reactions of Co n ±/0 clusters with water and oxygen. All these Co n ±/0 clusters were found to react with oxygen, but only anionic cobalt clusters give rise to water dissociation whereas the cationic and neutral ones are limited to water adsorption. We elucidate the influences of charge states, bonding modes and dehydrogenation mechanism of water on typical cobalt clusters. It is unveiled that the additional electron of anionic Co n - clusters is not beneficial to H 2 O adsorption, but allows for thermodynamics- and kinetics-favourable H atom transfer and dehydrogenation reactions. Apart from the charge effect, size effect and spin effect play a subtle role in the reaction process. The synergy of multiple metal sites in Co n - clusters reduces the energy barrier of the rate-limiting step enabling hydrogen release. This finding of water dissociation on cobalt clusters put forward new connotations on the activity series of metals, providing new insights into the corrosion mechanism of cobalt nanometals., (© 2024. The Author(s).)