Applied Nano

12 pages, 7441 KiB

Open AccessFeature PaperArticle

Black TiO₂ and Oxygen Vacancies: Unraveling the Role in the Thermal Anatase-to-Rutile Transformation

by Mattia Allieta, Mauro Coduri and Alberto Naldoni

Appl. Nano 2024, 5(2), 72-83; https://doi.org/10.3390/applnano5020007 - 3 May 2024

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Understanding the role of oxygen vacancies in the phase transformation of metal oxide nanomaterials is fundamental to design more efficient opto-electronic devices for a variety of applications, including sensing, spintronics, photocatalysis, and photo-electrochemistry. However, the structural mechanisms behind the phase transformation in reducible [...] Read more.

Understanding the role of oxygen vacancies in the phase transformation of metal oxide nanomaterials is fundamental to design more efficient opto-electronic devices for a variety of applications, including sensing, spintronics, photocatalysis, and photo-electrochemistry. However, the structural mechanisms behind the phase transformation in reducible oxides remain poorly described. Here, we compare P25 and black TiO₂ during the thermal anatase-to-rutile transformation using in situ synchrotron powder diffraction. The precise measurement of the phase fractions, unit cell parameters, and Ti-O bond sheds light on the phase transformation dynamics. Notably, we observe distinct temperature-dependent shifts in the relative phase fractions of anatase and rutile in both materials highlighting the role of the oxygen vacancy in promoting the phase transformation. We employ bond valence concepts for structural modeling, revealing unique trends in temperature evolution of Ti-O distances of black rutile, confirming that this TiO₂ phase is preferentially reduced over anatase. These findings not only enhance our understanding of phase transitions in TiO₂ but also open new ways for the design of advanced photocatalytic materials through targeted phase control. Full article

(This article belongs to the Collection Feature Papers for Applied Nano)

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14 pages, 6874 KiB

Open AccessArticle

Influence of Baccharis salicifolia Extract on Iron Oxide Nanoparticles in MCM-41@IONP and Its Application in Room-Temperature-Fabricated Metal–Insulator–Semiconductor Diodes

by Gerardo Miguel Bravo de Luciano, Blanca Susana Soto-Cruz, Anabel Romero-López, Yesmin Panecatl-Bernal, José Alberto Luna-López and Miguel Ángel Domínguez-Jiménez

Appl. Nano 2024, 5(2), 58-71; https://doi.org/10.3390/applnano5020006 - 26 Apr 2024

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Abstract

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, [...] Read more.

This work presents the green synthesis of iron oxide nanoparticles (IONPs) using Baccharis salicifolia extract and their incorporation in mesoporous silica MCM-41, obtaining an MCM-41@IONP composite. The MCM-41@IONP composite was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption and desorption, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The use of the natural reducing agent Baccharis salicifolia resulted in nanoparticles with an average size of 31 nm. Furthermore, we showcase the application of the MCM-41@IONP nanocomposite in a metal–insulator–semiconductor (MIS) diode, which was fabricated at room temperature. The current–voltage and capacitance–voltage curves of the MIS diode were carefully measured and subjected to detailed analysis. The results demonstrate the potential utility of MCM-41@IONP nanocomposite-based MIS diodes, suggesting their applicability in the design of biosensors or as discrete components in electronic devices. Full article

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10 pages, 1584 KiB

Open AccessCommunication

Quantum Mechanical Comparison between Lithiated and Sodiated Silicon Nanowires

by Donald C. Boone

Appl. Nano 2024, 5(2), 48-57; https://doi.org/10.3390/applnano5020005 - 1 Apr 2024

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Abstract

This computational research study will compare the specific charge capacity (SCC) between lithium ions inserted into crystallized silicon (c-Si) nanowires with that of sodium ions inserted into amorphous silicon (a-Si) nanowires. It will be demonstrated that the potential energy V(r) within a lithium–silicon [...] Read more.

This computational research study will compare the specific charge capacity (SCC) between lithium ions inserted into crystallized silicon (c-Si) nanowires with that of sodium ions inserted into amorphous silicon (a-Si) nanowires. It will be demonstrated that the potential energy V(r) within a lithium–silicon nanowire supports a coherent energy state model with discrete electron particles, while the potential energy of a sodium–silicon nanowire will be discovered to be essentially zero, and, thus, the electron current that travels through a sodiated silicon nanowire will be modeled as a free electron with wave-like characteristics. This is due to the vast differences in the electric fields of lithiated and sodiated silicon nanowires, where the electric fields are of the order of

10^{10}

V/m and

10^{- 15}

V/m, respectively. The main reason for the great disparity in electric fields is the presence of optical amplification within lithium ions and the absence of this process within sodium ions. It will be shown that optical amplification develops coherent optical interactions, which is the primary reason for the surge of specific charge capacity in the lithiated silicon nanowire. Conversely, the lack of optical amplification is the reason for the incoherent optical interactions within sodium ions, which is the reason for the low presence of SCC in sodiated silicon nanowires. Full article

(This article belongs to the Collection Feature Papers for Applied Nano)

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15 pages, 2590 KiB

Open AccessArticle

Synthesis and Characterization of B₄C-Based Multifunctional Nanoparticles for Boron Neutron Capture Therapy Applications

by Maria Paola Demichelis, Agustina Mariana Portu, Mario Alberto Gadan, Agostina Vitali, Valentina Forlingieri, Silva Bortolussi, Ian Postuma, Andrea Falqui, Elena Vezzoli, Chiara Milanese, Patrizia Sommi and Umberto Anselmi-Tamburini

Appl. Nano 2024, 5(2), 33-47; https://doi.org/10.3390/applnano5020004 - 25 Mar 2024

Viewed by 708

Abstract

Nanoparticles composed of inorganic boron-containing compounds represent a promising candidate as ¹⁰B carriers for BNCT. This study focuses on the synthesis, characterization, and assessment of the biological activity of composite nanomaterials based on boron carbide (B₄C). Boron carbide is a [...] Read more.

Nanoparticles composed of inorganic boron-containing compounds represent a promising candidate as ¹⁰B carriers for BNCT. This study focuses on the synthesis, characterization, and assessment of the biological activity of composite nanomaterials based on boron carbide (B₄C). Boron carbide is a compelling alternative to borated molecules due to its high volumetric B content, prolonged retention in biological systems, and low toxicity. These attributes lead to a substantial accumulation of B in tissues, eliminating the need for isotopically enriched compounds. In our approach, B₄C nanoparticles were included in composite nanostructures with ultrasmall superparamagnetic nanoparticles (SPIONs), coated with poly (acrylic acid), and further functionalized with the fluorophore DiI. The successful internalization of these nanoparticles in HeLa cells was confirmed, and a significant uptake of ¹⁰B was observed. Micro-distribution studies were conducted using intracellular neutron autoradiography, providing valuable insights into the spatial distribution of the nanoparticles within cells. These findings strongly indicate that the developed nanomaterials hold significant promise as effective carriers for ¹⁰B in BNCT, showcasing their potential for advancing cancer treatment methodologies. Full article

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Appl. Nano, Volume 5, Issue 2 (June 2024) – 4 articles

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