The formation of Ag nanoparticles is currently a topic subject to a great deal of research because they are excellent materials with many technological applications. Recently, the formation of Ag nanoparticles on a-Ag 2 WO 4 semiconductors induced by electron irradiation has been reported, but the mechanism underlying the transformations remains elusive. The aim of this article is to describe the mechanisms of electron beam irradiation on a-Ag 2 WO 4 and its transformation to form Ag nanoparticles in vacuum conditions. To this end, a combined study involving experiments and multiscale computational approaches (density functional theory calculations and molecular dynamics simulations) is presented. With the increasing interplay between experimental and computational approaches at multiple length scales, we will also discuss how these combined data can be used to provide a deep insight into the rationalization of electron beam-induced transformations. This phenomenon is likely to be promoted by electron charge redistribution in these materials due to electronic excitations combined with the formation of silver vacancies under electron beam irradiation. As this mechanism should be relevant to other Ag-based materials, our results provide pointers for the further development and optimization of electron beammediated engineering of the atomic structure and electronic properties at the atomic resolution. K E Y W O R D Sa-Ag 2 WO 4 , Ag nanoparticles, electron beam irradiation, first-principles calculations, plasmons | I N TR ODU C TI ONIn recent years, a strong continuous effort has been made in the synthesis of Ag nanoparticles (NPs) due to their remarkable properties and exciting applications in areas such as photonics, electronics, photocatalysis, sensing, and biomedicine. [1][2][3][4][5][6][7][8][9][10][11][12] The possibility of building new materials byThis article is dedicated to our colleague and friend, Prof. Nino Russo, as a tribute on the occasion of his 70th birthday. We hereby take this opportunity to convey our most heartfelt congratulations to an excellent person and a great researcher who possesses a privileged vision of interpersonal relations, teachinglearning processes, and technical-scientific innovations. combining metallic Ag with a semiconductor gives rise to a broad spectrum of synergistic and complementary properties that enable new applications to be developed, and many studies have revealed that the deposition of Ag on semiconductors enhances their photocatalytic activity due to the particular properties of Ag-based photocatalysts. [13,14] This phenomenon is related to the surface plasmon resonance, which improves the separation of the electron-hole pair. [15][16][17][18][19][20][21][22][23][24] The controlled combination of these two different materials is an interesting challenge, in which Ag NPs on the contact interface trigger structural and electronic variations that affect the photocatalytic performance of the semiconductor by increasing the electron-hole separation and then th...

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Metallic nanoalloys are essential because of the synergistic effects rather than the merely additive effects of the metal components. Nanoscience is currently able to produce one-atom-thick linear atomic chains (LACs), and the NiAl(110) surface is a well-tested template used to build them. We report the first study based on ab initio density functional theory methods of one-dimensional transition-metal (TM) nanoalloys (i.e., LACs) grown on the NiAl(110) surface. This is a comprehensive and detailed computational study of the effect of alloying groups 10 and 11 metals (Pd, Pt, Cu, Ag, and Au) in LACs supported on the NiAl(110) surfaces to elucidate the structural, energetic, and electronic properties. From the TM series studied here, Pt appears to be an energy-stabilization species; meanwhile, Ag has a contrasting behavior. The work function changes because the alloying in LACs was satisfactorily explained from the explicit surface dipole moment calculations using an ab initio calculation-based approach, which captured the electron density redistribution upon building the LAC.

Thin gold nanowires (NWs) are materials that could be used as support in different chemical reactions. Using density functional theory (DFT) it was shown that NWs that form linear atomic chains (LACs) are suitable for stimulating chemical reactions. To this end, the oxidation reaction of ethanol supported on the LACs of AuÀ NWs was investigated. Two types of LACs were used for the study, one pure and the other with an oxygen impurity. The results showed that the oxygen atom in the LAC fulfills important functions throughout the reaction pathway. Before the chemical reaction, it was observed that the LAC with impurity gains structural stability, that is, the oxygen acts as an anchor for the gold atoms in the LAC. In addition, the LAC was shown to be sensitive to disturbances in its vicinity, which modifies its nucleophilic character. During the chemical reaction, the oxidation of ethanol occurs through two different reaction paths and in two stages, both producing acetaldehyde (CH 3 CHO). The different reaction pathways are a consequence of the presence of oxygen in the LAC (oxygen conditions the formation of reaction intermediates). In addition, the oxygen in the LAC also modifies the kinetic behavior in both reaction stages. It was observed that, by introducing an oxygen impurity in the LAC, the activation energy barriers decrease ~69 % and ~97 % in the first and second reaction stages, respectively.

Este projeto visou estudar as principais propriedades que sistemas compostos pelo átomo de hidrogênio podem apresentar. Os sistemas em foco vão desde moléculas à estruturas cristalinas em diferentes arranjos de rede. Para tanto, são utilizados conceitos da mecânica quântica e da física do estado sólido, bem como métodos da física computacional.