Confined Growth of NiAl-Layered Double Hydroxide Nanoparticles Within Alginate Gel: Influence on Electrochemical Properties

Abstract

NiAl Layered Double Hydroxide (LDH) alginate bionanocomposites were synthesized by confined coprecipitation within alginate beads. The NiAl based bionanocomposites were prepared either by impregnation by divalent and trivalent metal cations of pre-formed calcium cross-linked alginate beads or by using the metal cations (Ni2+, Al3+) as crosslinking cationic agents for the biopolymer network. The impregnation step was systematically followed by a soaking in NaOH solution to induce the LDH coprecipitation. Powder x-ray diffraction (PXRD), infrared spectroscopy (FTIR), energy dispersive X-ray analysis (EDX), thermogravimetry analysis (TGA), electron microscopies (SEM and TEM) confirmed the biotemplated coprecipitation of LDH nanoparticles ranging from 75 to 150 nm for both strategies. The drying of the LDH@alginate beads by supercritical CO2 drying process led to porous bionanocomposite aerogels when Ca2+ cross-linked alginate beads were used. Such confined preparation of NiAl LDH was extended to bionanocomposite films leading to similar results. The permeability and the electrochemical behavior of these NiAl@alginate bionanocomposites, as thin films coated on indium tin oxide (ITO) electrodes, were investigated by cyclic voltammetry, demonstrating an efficient diffusion of the K4Fe(CN)6 redox probe through the LDH@alginate based films and the improvement of the electrochemical accessibility of the Ni sites.

A Comparison of Nitrate Release from Zn/Al-, Mg/Al-, and Mg–Zn/Al Layered Double Hydroxides and Composite Beads: Utilization as Slow-Release Fertilizers

“…The SEM micrograph of LB exhibits a porous nature. At higher magnifications, the LDH particles appeared to be covered by a polymer coating, which was characteristic of the biopolymer matrix, and this observation was similar to that reported by Prevot et al 72 for Ni/Al LDH-alginate bionanocomposites synthesized by confined coprecipitation. EDS spectrum of LB indicated the existence of Mg and Al at 1.25 and 1.48 keV as Kα X-ray signals together with carbon, nitrogen, oxygen, and calcium (used for cross-linking) (Figure 4e).…”

Layered double hydroxide-based nanomaterials for biomedical applications

“…11 Since the mid-20th century, LDHs have been extensively explored and shown great potential in a variety of applications, including optics, energy storage and conversion, environmental remediation, and catalysis, by virtue of their special layered structure, tunable chemical composition and appealing physicochemical properties (e.g., light, thermal, magnetic and ultrasonic response). [12][13][14][15][16][17][18][19][20][21] Since Choy et al proposed the concept of ''bio-ceramic nanohybrids'' in 1999, 22 multifunctional nanomaterials with a layered structure have been greatly explored for biomedical applications. Compared to widely explored layered nanomaterials (e.g., graphene, transition metal oxides (TMOs), silicate clays, etc.…”

Zn-Cr Layered Double Hydroxides for Photocatalytic Transformation of CO2 under Visible Light Irradiation: The Effect of the Metal Ratio and Interlayer Anion

“…The structure of LDHs is based on brucite-like layers with positive charge counterbalanced with interlayered anions [3,6,22,23]. Compositional flexibility of LDHs enables their use in different prominent applications, such as photocatalytic [24] and electrocatalytic [25] CO 2 reduction, CO 2 capture for environmental remediation [26], photocatalytic hydrogen production [27], pollutant degradation [28], lithium-sulfur batteries [29], and adsorbents of atmospheric pollutants (CO 2 , NO x , SO x and volatile organic compounds (VOCs)) [30], among others. The outstanding characteristics of LDHs, including their layered and tunable structure, their high thermal and chemical stability, their easy and inexpensive synthetic procedures, their optical features, their anion-exchange capacity and their high CO 2 adsorption capacity, make them exceptional materials for CO 2 PR [6,31].…”