scholarly journals Mesoporous silica supported Pd/Ag bimetallic nanoparticles as a plasmonic catalyst for chemoselective hydrogenation of p-nitrostyrene under visible light irradiation

2017 ◽  
Vol 129 (11) ◽  
pp. 1661-1669 ◽  
Author(s):  
Priyanka Verma ◽  
Miriam Navlani-García ◽  
Yasutaka Kuwahara ◽  
Kohsuke Mori ◽  
Hiromi Yamashita
Keyword(s):  
Mesoporous Silica ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Bimetallic Nanoparticles ◽  
Light Irradiation ◽  
Chemoselective Hydrogenation ◽  
Supported Pd

Pd/Ag and Pd/Au bimetallic nanocatalysts on mesoporous silica for plasmon-mediated enhanced catalytic activity under visible light irradiation

2016 ◽  
Vol 4 (26) ◽  
pp. 10142-10150 ◽  
Author(s):  
Priyanka Verma ◽  
Yasutaka Kuwahara ◽  
Kohsuke Mori ◽  
Hiromi Yamashita
Keyword(s):  
Catalytic Activity ◽  
Mesoporous Silica ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Systematic Comparison ◽  
Bimetallic Nanostructures ◽  
Bimetallic Nanocatalysts ◽  
Catalytic Performances

A systematic comparison of plasmonic properties and catalytic performances has been performed with Pd deposited bimetallic nanostructures of plasmonic Ag and Au.

Photocatalytic Sonogashira reaction over silicon carbide supported Pd–Cu alloy nanoparticles under visible light irradiation

2018 ◽  
Vol 8 (13) ◽  
pp. 3357-3362 ◽  
Author(s):  
Bing Wang ◽  
Yingyong Wang ◽  
Jiazhou Li ◽  
Xiaoning Guo ◽  
Gailing Bai ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Sonogashira Reaction ◽  
Alloy Nanoparticles ◽  
Mild Conditions ◽  
Cu Alloy ◽  
Ligand Free ◽  
Supported Pd

PdCu alloy nanoparticles supported on SiC can efficiently catalyze the Sonogashira reaction by visible light irradiation under ligand-free and mild conditions. The superior catalytic activity of PdCu catalysts was caused by the synergistic effect of PdCu alloy nanoparticles.

Synthesis of mesoporous silica-supported Ag nanorod-based bimetallic catalysts and investigation of their plasmonic activity under visible light irradiation

2017 ◽  
Vol 7 (12) ◽  
pp. 2551-2558 ◽  
Author(s):  
Priyanka Verma ◽  
Yasutaka Kuwahara ◽  
Kohsuke Mori ◽  
Hiromi Yamashita
Keyword(s):  
Mesoporous Silica ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Bimetallic Catalysts ◽  
Light Irradiation ◽  
Catalytic Performances

Bimetallic Ag nanorod-based heterogeneous plasmonic nanocatalysts were synthesized for obtaining excellent catalytic performances under visible light irradiation.

scholarly journals Visible Light Photocleavable Ruthenium-Based Molecular Gates to Reversibly Control Release from Mesoporous Silica Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1030 ◽  
Author(s):  
Yolanda Salinas ◽  
Oliver Brüggemann ◽  
Uwe Monkowius ◽  
Ian Teasdale
Keyword(s):  
Mesoporous Silica ◽  
Visible Light ◽  
Silica Nanoparticles ◽  
Visible Light Irradiation ◽  
Mesoporous Silica Nanoparticles ◽  
Control Release ◽  
Light Irradiation ◽  
Future Design ◽  
Release Studies ◽  
Safranin O

Herein we present hybrid mesoporous silica nanomaterials (MSN) with visible light-sensitive ruthenium complexes acting as gates. Two different [Ru(bpy)2L1L2]2+ complexes were investigated by grafting [Ru(bpy)2(4AMP)2](PF6)2 (RC1) and [Ru(bpy)2(PPh3)Cl]Cl (RC2) via two or one ligands onto the surface of mesoporous silica nanoparticles (MSNs), to give MSN1-RC1 and MSN2-RC2, respectively. The pores were previously loaded with a common dye, safranin O, and release studies were conducted. The number and position of the ligands were shown to influence the photocages behavior and thus the release of the cargo. Release studies from MSN1-RC1 in acetonitrile showed that in the dark the amount of dye released was minimal after 300 min, whereas a significant increase was measured upon visible light irradiation (ca. 90%). While successful as a photochemically-controlled gated system, RC1 was restricted to organic solvents since it required cleavage of two ligands in order to be cleaved from the surface, and in water only one is cleaved. Release studies from the second nanomaterial MSN2-RC2, where the complex RC2 was bound to the MSN via only one ligand, showed stability under darkness and in aqueous solution up to 180 min and, rapid release of the dye when irradiated with visible light. Furthermore, this system was demonstrated to be reversible, since, upon heating to 80 °C, the system could effectively re-close the pores and re-open it again upon visible light irradiation. This work, thus, demonstrates the potential reversible gate mechanism of the ruthenium-gated nanomaterials upon visible light irradiation, and could be envisioned as a future design of photochemically-driven drug delivery nanosystems or on/off switches for nanorelease systems.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

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