Synthesis of Co–Fe 1D Nanocone Array Electrodes Using Aluminum Oxide Template

Porous anodic alumina oxide (AAO) obtained via two-step anodization is a material commonly used as a template for fabricating 1D nanostructures. In this work, copper and cobalt-iron 1D nanocones were obtained by an electrodeposition method using AAO templates. The templates were produced using two-step anodization in H2C2O4. The Co–Fe nanostructures are characterized by homogeneous pore distribution. The electrocatalytic activity of the produced nanomaterials was determined in 1 M NaOH using the linear sweep voltammetry (LSV) and chronopotentiometry (CP) methods. These materials can be used as catalysts in the water-splitting reaction. The sample’s active surface area was calculated and compared with bulk materials.

The Synthesis and Characterization of Anodic Alumina Oxide Using Sulfuric Acid and Oxalic Acid

Anodic Alumina Oxide (AAO) is one of the nanomaterials that have developed as a template in the nanowires, nanodots and nanotubes. This research focuses on synthesizing AAO by two different electrolytic solutions which are using sulfuric acid (H2SO4) and oxalic acid (C2H2O4) by electrochemical anodization method. Two parameters were influencing the anodization process in the experiment; the type and the concentration of the electrolytic solution. The effects of the different type of electrolytic solutions produced different size of pores. When the voltage used is 25 V in H2SO4, the optimum reading size of the nanopores is in the range of 16-22 nm, whereas the AAO pores in C2H2O4 are in the range of 100-200 nm. Meanwhile, the concentration of H2SO4 and C2H2O4 is set to be 0.3 M, 0.4 M and 0.5 M., The results in 0.3 M H2SO4 and C2H2O4, show the optimum concentration of electrolytic solutions which is the key parameter affecting the morphological structure of porous membranes in AAO. The optimum value for these two acidic solutions has produced such highly ordered arrangement of nanopores which are from the average size of nanopores that anodized in sulfuric acid is 19 nm while 120 nm in oxalic acid. The morphological structure properties of AAO templates include the diameter of nanopores, the thickness of membrane and density of nanopores would be examined by Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray (EDX). Also, Fourier-transmittance infrared spectroscopy (FTIR) detected the chemical functional group of bonds in AAO. In conclusion, AAO templates have a big potential to be the major contributor in the future for the development of new electronic devices.

Nanoporous fluorescent sensor based on upconversion nanoparticles for the detection of dichloromethane with high sensitivity

We report a highly sensitive nanoporous fluorescence sensor based on core/shell upconversion nanoparticles (UCNPs) for the detection of dichloromethane. UCNPs are deposited on porous anodic alumina oxide templates to form a thin film-like gas sensor.

Engineering Leaf-Like UiO-66-SO3H Membranes for Selective Transport of Cations

Metal–organic frameworks (MOFs) with angstrom-sized pores are promising functional nanomaterials for the fabrication of cation permselective membranes (MOF-CPMs). However, only a few research reports show successful preparation of the MOF-CPMs with good cation separation performance due to several inherent problems in MOFs, such as arduous self-assembly, poor water resistance, and tedious fabrication strategies. Besides, low cation permeation flux due to the absence of the cation permeation assisting functionalities in MOFs is another big issue, which limits their widespread use in membrane technology. Therefore, it is necessary to fabricate functional MOF-CPMs using simplistic strategies to improve cation permeation. In this context, we report a facile in situ smart growth strategy to successfully produce ultrathin (< 600 nm) and leaf-like UiO-66-SO3H membranes at the surface of anodic alumina oxide. The physicochemical characterizations confirm that sulfonated angstrom-sized ion transport channels exist in the as-prepared UiO-66-SO3H membranes, which accelerate the cation permeation (~ 3× faster than non-functionalized UiO-66 membrane) and achieve a high ion selectivity (Na+/Mg2+ > 140). The outstanding cation separation performance validates the importance of introducing sulfonic acid groups in MOF-CPMs.

Effect of Current Density and Temperature on Template Assisted Cobalt Nanowire

Metal 1-D nanostructures are of special interest in industry applications because of their unique properties. Various synthesizing techniques have been employed to grow free standing and well dispersed nanowires. Among these methods, template assisted electrodeposition (TAE) is the most popular one because of its simplicity, cost effectiveness, high yield, ease of control over growth parameters, less contamination, and scalability to mass production. Processing conditions during the deposition process can affect the nanowire properties by a great deal. So far, these effects are not well established, and are in the early stages. In this work, we study the effect of current density and temperature on electrodeposited cobalt (Co) nanowire synthesized via template-assisted approach. Commercially available anodic alumina oxide templates were used for galvanostatic two electrode electrodeposition. Scanning electron microscopy was used to study the morphology of formed cobalt nanowires with EDS analysis confirming Co as main building element. Detailed XRD analysis was performed to find crystal orientation as well as crystal size.

Bioinspired enamel-like oriented minerals on general surfaces: towards improved mechanical properties

Enamel-like oriented hydroxyapatite minerals were obtained on general surfaces by a biomimetic, anodic alumina oxide (AAO)-assisted, double-layered gel system.