Elucidating the real-time Ag nanoparticle growth on α-Ag<sub>2</sub>WO<sub>4</sub>during electron beam irradiation: experimental evidence and theoretical insights

Pereira, Wyllamanney da Silva; Andrés, Juán; San-Miguel, Miguel A.; Silva, E. Z. da; Longo, E.; Longo, Valeria

doi:10.1039/c4cp05849f

Cited by 56 publications

(59 citation statements)

References 76 publications

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“…In particular, under conditions that limit the dissipation of thermal energy and charge to a sufficient extent, the formation and growth of Ag NPs have been observed to occur in α‐Ag 2 WO 4 under in situ electron beam irradiation in SEM and TEM. The mechanisms underlying Ag NPs growth are still unknown and theoretical studies are contributing to gain insights into the atomistic processes involved …”

Section: Introductionmentioning

confidence: 99%

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

Andrés

Gouveia

Gracia

et al. 2017

Int J of Quantum Chemistry

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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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Section: Introductionmentioning

confidence: 99%

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

Andrés

Gouveia

Gracia

et al. 2017

Int J of Quantum Chemistry

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“…The reasons for this phenomena have been discussed in recent publications 19,22,24,25 , and the production of Ag NPs on α-Ag 2 WO 4 19, 26-29 , β-Ag 2 MoO 4 30 , and Ag 3 PO 4 23 resulted in interesting applications as sensors, photoluminescent materials, visible-light photocatalysts, and bactericide materials. In this work, we will report, discuss and analyze, for first time, the nucleation process and early evolution of Ag nanoparticles on β-AgVO 3 crystals, provoked by an electron beam, by means of the joint use of an experimental and theoretical studies.…”

Section: Introductionmentioning

confidence: 99%

An Experimental and Computational Study of β-AgVO₃: Optical Properties and Formation of Ag Nanoparticles

et al. 2016

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“…Silver tungstate ĲAg 2 WO 4 ) is an important multifunctional material with an orthorhombic structure that exhibits various physical and chemical properties such as photoluminescence, [1][2][3][4][5][6] photocatalysis, 7-9 ozone gas sensing, 10 and antibacterial activity against Gram-negative and Gram-positive bacterial strains, for example, Escherichia coli, Bacillus subtilis, ganisms on Earth that are capable of producing all components found in basic organic compounds. 27 The presence of E. coli in H 2 O or food is indicative of contamination with human or animal feces.…”

Section: Introductionmentioning

confidence: 99%

Facet-dependent photocatalytic and antibacterial properties of α-Ag₂WO₄crystals: combining experimental data and theoretical insights

Roca

Sczancoski

Nogueira

et al. 2015

Catal. Sci. Technol.

125

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In this paper, we have combined the various experimental results and first-principles calculations with a new and interesting discussion to explain the photocatalytic and antibacterial activities of α-Ag 2 WO 4 crystals, which were obtained using the microwave-hydrothermal (MH) method with anionic surfactants. The advantages of the insights gained through the present work are two-fold. First, the mechanism and origin of the photocatalytic and antibacterial activities can be rationalized. Second, this facile and controllable synthetic method is expected to encourage the synthesis of complex metal oxides with specific active facets, and these insights can contribute to the rational design of new materials for multifunctional applications. X-ray diffraction and Rietveld refinement analysis confirmed that all the crystals have an orthorhombic structure without deleterious phases. Ultraviolet-visible diffuse reflectance spectroscopy indicated the presence of intermediary energy levels and a variation in the optical band gap values (3.09-3.14 eV) with the crystal growth process.The geometry, electronic properties of the bulk, and surface energies of these crystals were evaluated using first-principles quantum mechanical calculations based on the density functional theory. The crystal shapes was experimentally and theoretically modeled based on Rietveld refinement data, emission scanning electron microscopy images, and Wulff construction. To obtain a wide variety of crystal shapes, the morphologies were gradually varied by tuning the surface chemistry, i.e., the relative stability of the faceted crystals. The growth mechanisms of different α-Ag 2 WO 4 crystals and their facet-dependent photocatalytic and antibacterial performances were explored in details. The combination of experimental and theoretical data revealed the presence of (110) and (011) planes with high surface energies together with the disappearance of faces related to the Ĳ010)/Ĳ010) planes in α-Ag 2 WO 4 crystals are key factors that can rationalize both the photocatalytic and antibacterial activities. The different activities may be attributed to the different number of unsaturated superficial Ag and W atoms capable of forming the main active adsorption sites. Finally, we discuss how knowledge of surface-specific properties can be utilized to design a number of crystal morphologies that may offer improved performance in various applications.

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Elucidating the real-time Ag nanoparticle growth on α-Ag₂WO₄during electron beam irradiation: experimental evidence and theoretical insights

Cited by 56 publications

References 76 publications

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

An Experimental and Computational Study of β-AgVO₃: Optical Properties and Formation of Ag Nanoparticles

Facet-dependent photocatalytic and antibacterial properties of α-Ag₂WO₄crystals: combining experimental data and theoretical insights

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Elucidating the real-time Ag nanoparticle growth on α-Ag2WO4during electron beam irradiation: experimental evidence and theoretical insights

Cited by 56 publications

References 76 publications

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

Formation of Ag nanoparticles under electron beam irradiation: Atomistic origins from first‐principles calculations

An Experimental and Computational Study of β-AgVO3: Optical Properties and Formation of Ag Nanoparticles

Facet-dependent photocatalytic and antibacterial properties of α-Ag2WO4crystals: combining experimental data and theoretical insights

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Elucidating the real-time Ag nanoparticle growth on α-Ag₂WO₄during electron beam irradiation: experimental evidence and theoretical insights

An Experimental and Computational Study of β-AgVO₃: Optical Properties and Formation of Ag Nanoparticles

Facet-dependent photocatalytic and antibacterial properties of α-Ag₂WO₄crystals: combining experimental data and theoretical insights