Tunable magneto-photonic response of nickel nanostructures

In this letter, we present both experimental and numerical studies of the magneto-optical (MO) properties of nickel infiltrated opals. Ni can show interesting MO properties that can be controlled by nanostructuration through colloidal crystals templating. Nanostructuration allows the coupling of light to surface plasmon modes of Ni, and a clear dependence of the MO response as a function of the structural parameters of the template has been observed. This dependence can be used in future tunable devices such as switchers or MO modulators. © 2011 American Institute of Physics.This work has been partially supported by EU FP7 (NoE Nanophotonics 4 Energy Grant No. 248855 and NMP3-SL-2008-214107-Nanomagma); the CSIC PIF08-016, the Spanish MICINN (CSD2007-0046-Nanolight.es, CSD2008-00023-Funcoat, MAT2009-07841-GLUSFA, MAT2008-06765-C02-01/NAN-MAGPLAS) and Comunidad de Madrid (S2009/MAT-1756-PHAMA and S2009/TIC–1476- MICROSERES).Peer Reviewe

A facile co-precipitation synthesis of heterostructured ZrO₂/ZnO nanoparticles as efficient photocatalysts for wastewater treatment

Gnm3Altres ajuts: Basque Government ELKARTEK, FN KK-2015/0010ZrO₂-decorated ZnO (ZrO₂/ZnO) nanoparticles (NPs) have been synthesized by a facile co-precipitation method in the presence of cetyltrimethylammonium bromide (CTAB) surfactant. The ZrO₂ amount in the NPs has been varied from 1.0, 2.0, 4.9, to 9.3% by weight. The resulting NPs are heterostructured and consist of a crystalline ZnO core (wurtzite phase) surrounded by an amorphous ZrO₂ layer. X-ray diffraction analyses support this observation. The NPs show a narrow size distribution and are slightly elongated. Compared to pure ZnO NPs, the hybrid ZrO₂/ZnO ones show enhanced photocatalytic activity toward the degradation of Rhodamine B under UV-Vis light. Such enhancement has been partly attributed to the increased amount of oxygen vacancies when ZrO₂ is incorporated into the NPs, as shown by X-ray photoelectron spectroscopy analyses

Room-temperature synthesis of three-dimensional porous ZnO@CuNi hybrid magnetic layers with photoluminescent and photocatalytic properties

A facile synthetic approach to prepare porous ZnO@CuNi hybrid films is presented. Initially, magnetic CuNi porous layers (consisting of phase separated CuNi alloys) are successfully grown by electrodeposition at different current densities using H₂ bubbles as a dynamic template to generate the porosity. The porous CuNi alloys serve as parent scaffolds to be subsequently filled with a solution containing ZnO nanoparticles previously synthesized by sol-gel. The dispersed nanoparticles are deposited dropwise onto the CuNi frameworks and the solvent is left to evaporate while the nanoparticles impregnate the interior of the pores, rendering ZnO-coated CuNi 3D porous structures. No thermal annealing is required to obtain the porous films. The synthesized hybrid porous layers exhibit an interesting combination of tunable ferromagnetic and photoluminescent properties. In addition, the aqueous photocatalytic activity of the composite is studied under UV−visible light irradiation for the degradation of Rhodamine B. The proposed method represents a fast and inexpensive approach towards the implementation of devices based on metal-semiconductor porous systems, avoiding the use of post-synthesis heat treatment steps which could cause deleterious oxidation of the metallic counterpart, as well as collapse of the porous structure and loss of the ferromagnetic properties

Ni-, Pt- and (Ni/Pt)-doped TiO₂ nanophotocatalysts : a smart approach for sustainable degradation of Rhodamine B dye

Ni (1 wt%)-, Pt (1 wt%)- and [Ni (0.5 wt%)/Pt (0.5 wt%)]-doped TiO₂ nanoporous catalysts have been successfully obtained through a facile two-step hydrothermal route. TiO₂ crystallizes mostly in the anatase phase and acts as a mesoporous matrix. Meanwhile, Ni, Pt and Ni/Pt dopants form small nanoparticles (NPs) (3-95 nm in diameter) which are hosted by the TiO₂ framework. The resulting composites exhibit a rather large surface area, in the range of 186-200 m2/g. The band gap energy reduces from 3.03 eV for the undoped TiO₂ to 2.15 eV for the Pt-loaded TiO₂. As a consequence, absorption expands toward the visible light range. The photodegradation of Rhodamine B dye in aqueous medium has been investigated under UV-vis light irradiation. The presence of Ni, Pt and Ni/Pt NPs significantly enhances the photocatalytic activity of the material. Furthermore, the Ni-doped TiO₂ shows ferromagnetic behavior at room temperature, which makes its recovery and subsequent fast reutilization possible. Interestingly, this sample also exhibits the best stability upon recycling. Considering all the current challenges in sustainable water remediation, these new photocatalysts could find applications in real environmental contexts in the near future

Azobenzene-Appended Bis-Cyclometalated Iridium(III) Bipyridyl Complexes

A new synthetic route toward photochromic azobenzene-appended bipyridyl ligands has been developed, and 20 new cationic iridium­(III) bis-cyclometalated complexes containing up to four azobenzene fragments on their structure have been synthesized and characterized electronically and spectroscopically. These compounds incorporate photochromic azobenzene units in their neutral pyridyl ligands <b>1</b>–<b>5</b>, and in four of them azobenzenes have been also introduced <i>a posteriori</i> on their phenylpyridyl ligands by palladium-catalyzed cross-coupling. UV–vis-monitored light-triggered <i>trans</i>-to-<i>cis</i> isomerization of the azobenzene-appended ligands revealed a strong inhibition of this process upon coordination to the d⁶-metal ion. TD-DTF calculations revealed that this inhibition could be a consequence of a metal to ligand charge transfer relaxation process

Azobenzene-Appended Bis-Cyclometalated Iridium(III) Bipyridyl Complexes

A new synthetic route toward photochromic azobenzene-appended bipyridyl ligands has been developed, and 20 new cationic iridium­(III) bis-cyclometalated complexes containing up to four azobenzene fragments on their structure have been synthesized and characterized electronically and spectroscopically. These compounds incorporate photochromic azobenzene units in their neutral pyridyl ligands <b>1</b>–<b>5</b>, and in four of them azobenzenes have been also introduced <i>a posteriori</i> on their phenylpyridyl ligands by palladium-catalyzed cross-coupling. UV–vis-monitored light-triggered <i>trans</i>-to-<i>cis</i> isomerization of the azobenzene-appended ligands revealed a strong inhibition of this process upon coordination to the d⁶-metal ion. TD-DTF calculations revealed that this inhibition could be a consequence of a metal to ligand charge transfer relaxation process

Room-temperature synthesis of three-dimensional porous ZnO@CuNi hybrid magnetic layers with photoluminescent and photocatalytic properties

A facile synthetic approach to prepare porous ZnO@CuNi hybrid films is presented. Initially, magnetic CuNi porous layers (consisting of phase separated CuNi alloys) are successfully grown by electrodeposition at different current densities using H₂ bubbles as a dynamic template to generate the porosity. The porous CuNi alloys serve as parent scaffolds to be subsequently filled with a solution containing ZnO nanoparticles previously synthesized by sol-gel. The dispersed nanoparticles are deposited dropwise onto the CuNi frameworks and the solvent is left to evaporate while the nanoparticles impregnate the interior of the pores, rendering ZnO-coated CuNi 3D porous structures. No thermal annealing is required to obtain the porous films. The synthesized hybrid porous layers exhibit an interesting combination of tunable ferromagnetic and photoluminescent properties. In addition, the aqueous photocatalytic activity of the composite is studied under UV−visible light irradiation for the degradation of Rhodamine B. The proposed method represents a fast and inexpensive approach towards the implementation of devices based on metal-semiconductor porous systems, avoiding the use of post-synthesis heat treatment steps which could cause deleterious oxidation of the metallic counterpart, as well as collapse of the porous structure and loss of the ferromagnetic properties

Room-temperature synthesis of three-dimensional porous ZnO@CuNi hybrid magnetic layers with photoluminescent and photocatalytic properties

<p>A facile synthetic approach to prepare porous ZnO@CuNi hybrid films is presented. Initially, magnetic CuNi porous layers (consisting of phase separated CuNi alloys) are successfully grown by electrodeposition at different current densities using H₂ bubbles as a dynamic template to generate the porosity. The porous CuNi alloys serve as parent scaffolds to be subsequently filled with a solution containing ZnO nanoparticles previously synthesized by sol-gel. The dispersed nanoparticles are deposited dropwise onto the CuNi frameworks and the solvent is left to evaporate while the nanoparticles impregnate the interior of the pores, rendering ZnO-coated CuNi 3D porous structures. No thermal annealing is required to obtain the porous films. The synthesized hybrid porous layers exhibit an interesting combination of tunable ferromagnetic and photoluminescent properties. In addition, the aqueous photocatalytic activity of the composite is studied under UV−visible light irradiation for the degradation of Rhodamine B. The proposed method represents a fast and inexpensive approach towards the implementation of devices based on metal-semiconductor porous systems, avoiding the use of post-synthesis heat treatment steps which could cause deleterious oxidation of the metallic counterpart, as well as collapse of the porous structure and loss of the ferromagnetic properties.</p

Introducing Axial Chirality into Mesoionic 4,4′-Bis(1,2,3-triazole) Dicarbenes

Mesoionic 4,4′-bis(1,2,3-triazole-5,5′-diylidene) Rh(I) complexes having a C2 chiral 4,4′-axis were accessed from 3-alkyltriazolium salts in virtually complete de. Their structure and configurational integrity were assessed by NMR spectroscopy, X-ray crystallography, and chiral HPLC. Computational analysis of the MICs involved in the reaction suggested the formation of a highly stable and unprecedented cation-carbene intermediate species, which could be evidenced experimentally by cyclic voltammetry analysis