Search

One-dimensional iron hydroxide@cadmium hydroxide nanostructures have been prepared by sequentially converting cadmium hydroxide into iron hydroxide via simple and cost-effective cation exchange reaction based on solubility product to design electrochemical supercapacitive electrode. Surface architecture of iron hydroxide@cadmium hydroxide nanostructures in the form of core–shell enables easy and effective electrochemical reactions which have been studied via electrochemical cyclic voltammetry and charge–discharge studies. Interestingly, iron hydroxide@cadmium hydroxide electrode exhibits specific capacitance of 368 F g−1 at current density of 0.5 A g−1 along with electrochemical impedance analysis. Capacitance retention performed at the scan rate of 50 mV s−1 for 5000 cycles results in 52% capacity of its initial.

Powered by a renewable electricity source, electrochemical CO2 reduction reaction is a promising solution to facilitate the carbon balance. However, it is still a challenge to achieve a desired product with commercial current density and high efficiency. Herein we designed quasi-square-shaped cadmium hydroxide nanocatalysts for CO2 electroreduction to CO. It was discovered that the catalyst is very active and selective for the reaction. The current density could be as high as 200 mA cm−2 with a nearly 100% selectivity in a commonly used H-type cell using the ionic liquid-based electrolyte. In addition, the faradaic efficiency of CO could reach 90% at a very low overpotential of 100 mV. Density functional theory studies and control experiments reveal that the outstanding performance of the catalyst was attributed to its unique structure. It not only provides low Cd–O coordination, but also exposes high activity (002) facet, which requires lower energy for the formation of CO. Besides, the high concentration of CO can be achieved from the low concentration CO2via an adsorption-electrolysis device., Quasi-square cadmium hydroxide nanocrystals (Cdhy-QS) showed outstanding performance for electroreduction CO2 to CO.

In this study, firstly cadmium hydroxide nanopowder was evolved by cost-effective wet chemical co-precipitation method. The transformation of nanocrystalline Cu2+–Mn2+-co-doped CdO occurred via thermal decomposition of the obtained hydroxide at 750 °C. The structural, optical and electrical behavior of nanocrystallites was analyzed by different complementary measuring tools. DTA of the as-prepared sample exhibited an endothermic peak at 240 °C attributed to crystallization. XRD analysis depicted a multiphase structure in the as-prepared sample, and pure rocksalt structure was obtained after annealing. Cu2+–Mn2+-co-doped cubic CdO has been achieved first time which was further confirmed by FTIR with various stretching and bending vibrations of Cd–O at 720, 625 and 460 cm−1. SEM–TEM images demonstrated the brain-like morphology of different hexagonal and spherical nanocrystallites with an average size of ~ 35 nm. In addition, optical band gap energy was found in the range 2.14–2.44 eV by Tauc’s plot. In photoluminescence results, emission spectra have many bands at 420, 480, 550 nm originated from excitonic transition, structural defects and oxygen vacancies, while intense peak at 450, 520 nm may be ascribed to Cu2+ and Mn2+ dopants, respectively. Hall measurements demonstrated that the Cu2+–Mn2+-co-doped CdO with a pure cubic phase has superior semiconducting behavior. The homogeneous codoping of Cu2+–Mn2+ leads to efficient modification in structural, optical and electrical parameters of CdO which would make such materials attractive for semiconductor and photovoltaic industry, etc.

An emerging non-noble-metal-based oxygen evolution reaction (OER) electrocatalyst, cadmium hydroxide (Cd(OH)2), has been developed in this work; this was prepared via a facile chemical precipitatio...

To solve energy crisis, the engineering of highly efficient and cost-effective photoanodes is urgently required for clean fuel generation. Herein, CdSe(en)0.5 (en = ethylenediamine) hybrid photoanodes were synthesized by a solvothermal approach. It was revealed that a second in situ hydrothermal treatment successfully converts cadmium foil-based inorganic-organic CdSe(en)0.5 (en = ethylenediamine) hybrid nanosheets to an oriented cadmium hydroxide crowned CdSe nanowire-decorated porous nanosheet (Cd(OH)2/CdSe NW/NS) heterostructure by dissolution and regrowth mechanisms. The alteration in second hydrothermal reaction conditions could modify the morphology and optical properties of the Cd(OH)2/CdSe NW/NS heterostructure photoanodes. The possible growth mechanism of the Cd(OH)2/CdSe NW/NS porous structure is studied at various second hydrothermal times using the control experiments of the synthesis. The optimized 3D porous Cd(OH)2/CdSe NW/NS photoanodes exhibited an outstanding photocurrent density of 6.1 mA cm-2 at 0 V vs. Ag/AgCl, which is approximately 7.6 times higher than that of the inorganic-organic CdSe(en)0.5 hybrid under light irradiation (>420 nm cut off filter). A mechanism is proposed to explain the enhanced charge separation at the Cd(OH)2/CdSe NW/NS photoanode/electrolyte interface, which is supported by PL and photoelectrochemical analyses. These findings open an avenue of phase and morphology transmutation for efficient formation of other hierarchical structures of metal selenides and sulfides. Additionally, the Al2O3 co-catalyst can act as effective hole trapping sites and improves the stability of the photoelectrode through the timely consumption of photogenerated charges, particularly holes.

Electrochemical capacitors are deemed to be the most prospective energy storage devices in the field of alternative energy sources. Here, cadmium hydroxide (Cd(OH)2) nanosheets are hydrothermally synthesized and used as electrodes for supercapacitors. Physiochemical properties of the as-synthesized materials are examined using powder x-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and energy-dispersive x-ray spectroscopy measurements. Electrochemical investigations reveal an excellent operating potential window of 1.5 V, with the specific capacitance of ∼ 71 F g−1 at a scan rate of 2 mV s−1. In addition, the Cd(OH)2 electrodes are complemented by good cyclic retention for 2000 cycles. Further, the analysis of the type of charge-storage mechanism reveals prominent contributions from the diffusion-controlled processes.

Thin film consisting of hierarchical cadmium oxide nanonecklaces has been synthesized through room temperature chemically deposited cadmium hydroxide nanowires as template followed by air annealing. Formation of thin film has been confirmed with aid of structural, surface morphological, valence state and optical, studies performed by X-ray diffraction, Raman analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV–visible spectroscopy. Air annealing at 330 °C has enhanced the photo electrochemical power conversion efficiency of the CdO as photoanode to 0.21% configured through platinum as counter electrode and polyiodide as a liquid electrolyte. Complete device performance have been correlated through rate of recombination, and electron life time. The schematic energy band alignment also has been comprehended herein.

The Ni foil or fluorine-doped SnO2 transparent conductive glass substrates modified by BiFeO3 film with a different atomic ratio of Bi to Fe were prepared by the method of spin coating-calcination at a different temperature. Coupling photo-catalysis with electro-catalysis, resourceful treatment of salty organic wastewater containing methyl orange and cadmium ion was proposed and experimentally achieved. Under visible light irradiation, the highest H2-production rate (5.46 ml/h cm2), degradation efficiency of methyl orange (51.6%), and the recovery precipitation weight of cadmium hydroxide (0.1846 g) were obtained with Ni foil modified by BiFeO3 (Bi:Fe = 1.10:1.00) film at 550°C of calcination. X-ray diffraction, ultraviolet–visible diffuse reflectance spectroscopy, scanning electron microscopy, and the resourceful treatment test of salty organic wastewater were used to characterise the catalyst film.

Utilization of natural clay minerals for the treatment of heavy metal cadmium contamination is appealing as the affordable and readily accessible raw materials. However, the low reactivity of natural serpentine limits its practical application for Cd removal. In the present study, mechanochemical activation of antigorite-type serpentine (SP) as example was introduced to enhance its removal capacity for heavy metal of cadmium high enough for practical use. It was found ball-milling at 600 rpm for 60 min for antigorite resulted in the increased release of hydroxyl group to facilitate the precipitation of Cd2+, giving a capacity of 27.4 mg/g for the treatment of 100 mg/L Cd2+ for 120 min at room temperature, which was 10 times higher than that of the pristine antigorite (2.5 mg/g). More significantly, magnesium sulfate (MgSO4, MS) was introduced for the first time to process antigorite, thus to form MgSO4-incorporated antigorite. As a result, the removal capacity for Cd2+ was dramatically increased to 239.7 mg/g with the equal antigorite dosage (the molar ratio of SP/MS = 1:0.5), which is also much higher than the other reported clay minerals. Results showed that, MgSO4 incorporation promoted the reactivity of antigorite and provided numerous SO42− active sites, which allowed the heterogeneous nucleation of basic cadmium sulfate (CdSO4·3.5 Cd(OH)2·xH2O) precipitate on antigorite, therefore not requiring high alkalinity support as the conventional formation of cadmium hydroxide does. Correspondingly, under the new mechanism, the Cd precipitation could take place in a wide pH range, even from pH 3.0, which was a rarely reported phenomenon happening on natural minerals. Based on these findings, this study demonstrated the effectiveness of mechanochemical incorporation of sulfate for enhancing the Cd2+ removal capacity of serpentine, as well as the high efficiency of new pathway for Cd2+ precipitation. Moreover, the potential of low-cost serpentine as alternative stabilizers for the highly-effective remediation of heavy metal contamination may be expected.

This research reports a simple method for the controlled synthesis of cadmium oxide (CdO) and cadmium hydroxide (Cd(OH) 2 ) with different morphology in the presence of NaBH 4 or LiBH 4 as reducing agent, by using k-carrageenan as a capping agent and potassium bromide as a template. The synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impacts of reducing agent, reaction atmosphere and concentration of reducing agent on size and morphology of the particles were discussed. We suggested that chemical etching and Kirkendall effect play a key role on morphology of particles, and the etch rate depends on reducing agent concentration. It was found that by increasing the concentration of reducing agent the intensified etching lead to an increase in the size of the particles. The results show an increase in particle size with decreasing reducing agents power. The various morphologies obtained for CdO and Cd(OH) 2 such as hollow cube, macro rod, nanoplate and macroplate were discussed based on the Kirkendall effect and chemical etching. Finally, the antibacterial activity was screened against Escherichia coli and Staphylococcus aureus . The inhibition zones were ranged from 36-47 mm and 25-47 mm for different morphologies of CdO and Cd(OH) 2 respectively.

Circulating fluidized bed (CFB) fly ash is an industrial waste produced from the burning of coal gangue by the CFB technology. We investigated the removal of Cd2+ from wastewater by a hydrothermally modified CFB fly ash (HM-CFB-FA) adsorbent material. The SEM and BET analyses of HM-CFB-FA indicated that the adsorbent was rich in porous structure and had a huge specific surface area. Also, the XRF, XRD, and FTIR characterization of the adsorbent material demonstrated that HM-CFB-FA was rich in zeolite content, which indicates that the adsorbent has excellent adsorption capability. The results of the conditional experiments showed that the adsorbent dosage, solution pH, initial Cd2+ concentration, temperature, and the contact time had a remarkable effect on the adsorption performance of HM-CFB-FA. Under the optimal conditions, the maximum adsorption capacity of Cd2+ by HM-CFB-FA reached 183.7 mg/g. The adsorption isotherm analysis revealed that the adsorption of Cd2+ by HM-CFB-FA was well fitted to the Langmuir model. The kinetic investigation showed that Cd2+adsorption by HM-CFB-FA was controlled by surface reaction and external diffusion processes. The mechanism analysis demonstrated that the adsorption of HM-CFB-FA and the formation of cadmium hydroxide may be responsible for the removal of Cd2+ from aqueous solution. Therefore, it was concluded that HM-CFB-FA is a promising low-cost adsorbent for the removal of Cd2+ from wastewater.

The aim of this study is investigation of fouling propensity in nickel cadmium electrodes after degradation of alkaline-electrolyte from rich-hydroxide to rich-carbonate along with time. Gradually, CO2 absorption from the air into the alkaline electrolyte leads to the destruction of electrodes and the formation of precipitated layers resulting in reduction of electrical capacity and life time of batteries. Based on the microscopic observations (SEM), spectroscopic evidences (FTIR and XRD) and thermal experiments (TG-DTA) significant damages and fouling phenomena were categorized as: salt islands, graphite films, etched graphite, cadmium dendrites, cadmium oxide/sulfide and cathodic corrosion. The experimental results revealed that nickel cathodes have experienced more surface damages with respect to cadmium anodes. Although the anode is the source of cadmium species, however the fouling layers of cadmium oxide and cadmium sulfide were assigned to be the main causes of cathode damage, leading to the decreasing of electrode current and the increasing of internal resistance of the cells. On the other hand, the main damage on the surface of anode electrode was attributed to graphite coatings and cadmium hydroxide stripped from the cathode. The microscopic observations showed that almost 2% of cathode surface was corroded, while the anode surface had experienced no corrosion.

Nanofiber cadmium oxide (CdO) thin films were prepared on glass substrates at room temperature and a deposition time of 4 hrs. The obtained thin films were annealed in air at various temperature. The XRD results verified that the as-deposited thin film was exhibited hexagonal structure of Cadmium hydroxide, however, as the annealing temperature increased to 450 °C new face center cubic crystal structure of CdO thin films were obtained. The EDX analyses established the presence of Cd and O elements. The SEM study revealed that the prepared CdO thin films have nanofiber networks. The optical band gap decreased from 2.42 to 1.94 eV as the annealing temperature increased. Green emission was observed as the prepared materials were excited at 250 nm. The refractive index and plasma frequencies were varied with annealing temperature. The resistivity of the prepared nanofiber were found in the range of 1.32410−3 to 5.265×10−3 Ω cm.

A new plasma-solution method of the CdO ultradisperse powders synthesis was described. The atmospheric pressure direct current discharge was excited in the ambient air by applying a high direct voltage to two pointed titanium electrodes placed above liquid anode and liquid cathode in the H-shaped cell. The discharge current was 40 mA and the total input power was about 40 W. The action of the DC glow discharge on the cadmium nitrate water solution in the absence of additional reagents and without electrodes-solution contact was shown to result in the production of the solids in the liquid phase. The kinetics of particles formation was studied using turbidimetry and nephelometry methods. Powders’ chemical composition and morphology was obtained using X-ray diffraction spectroscopy (XRD), electron-dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), differential-scanning calorimetry (DSC) and scanning electron microscopy (SEM). It was found that as-synthesized powders are not the pure cadmium hydroxide but the mixture of the cadmium nitrate, hydroxy nitrate and hydroxide. Some assumptions regarding the mechanisms and pathway of the chemical processes both under the plasma action on the solution and during the calcination of as-synthesized powders were discussed.

Cd(OH)2 ultrafine nanowires with a high aspect ratio were fabricated by the hydrothermal method and were subsequently used as a sacrificial template to generate Cd(OH)2/CdS nanowires. The transmission electron microscopy results show that the length of the nanowires reached several micrometres, and the diameter of the nanowires was approximately 10–20.0 nm. The charge transport properties of the Cd(OH)2 and Cd(OH)2/CdS nanowires assembled on comb Au electrodes was also investigated. The I-V results showed that the current intensity of the Cd(OH)2/CdS nanowires was increased by four orders of magnitude compared with the Cd(OH)2 nanowires, achieving 10−10 A.

We report on an ultrasensitive metal-labeled amperometric immunoassay of proteins, which is based on the selective staining of nanocrystalline cadmium sulfide (CdS) on ZnO nanocrystals and in-situ microliter-droplet anodic stripping voltammetry (ASV) detection on the immunoelectrode. Briefly, antibody 1 (Ab1), bovine serum albumin (BSA), antigen and ZnO-multiwalled carbon nanotubes (MWCNTs) labeled antibody 2 (Ab2-ZnO-MWCNTs) were successively anchored on a β-cyclodextrin-graphene sheets (CD-GS) nanocomposite modified glassy carbon electrode (GCE), forming a sandwich-type immunoelectrode (Ab2-ZnO-MWCNTs/antigen/BSA/Ab1/CD-GS/GCE). CdS was selectively grown on the catalytic ZnO surfaces through chemical reaction of Cd(NO3)2 and thioacetamide (ZnO-label/CdS-staining), due to the presence of an activated cadmium hydroxide complex on ZnO surfaces that can decompose thioacetamide. A beforehand cathodic "potential control" in air and then injection of 7 μL of 0.1 M aqueous HNO3 on the immunoelectrode allow dissolution of the stained CdS and simultaneous cathodic preconcentration of atomic Cd onto the electrode surface, thus the following in-situ ASV detection can be used for immunoassay with enhanced sensitivity. Under optimized conditions, human immunoglobulin G (IgG) and human heart-type fatty-acid-binding protein (FABP) are analyzed by this method with ultrahigh sensitivity, excellent selectivity and small reagent-consumption, and the limits of detection (LODs, S/N=3) are 0.4 fg mL−1 for IgG and 0.3 fg mL−1 for FABP (equivalent to 73 FABP molecules in the 6 μL sample employed).

Simple chemical route has been employed to grow interconnected nanobeads of CdO having necklace like structure through air annealing of cadmium hydroxide nanowires. This nanobeads of n-CdO with high surface area has been decorated with p-PbS nanoparticles resulting in the formation of nano-heterojunction which has been utilized effectively as room temperature liquefied petroleum gas (LPG) sensor. The room temperature gas response towards C2H5OH, Cl2, NH3, CO2 and LPG was investigated, among which LPG exhibits significant response. The maximum gas response of 51.10% is achieved with 94.54% stability upon exposure of 1176 ppm concentration of LPG at room temperature (27 °C). The resulting parameters like gas response, response and recovery time along with stability studies has been studied and results are discussed herein.

A facile, low temperature and low cost one-step template-free approach is presented for the fabrication of cadmium hydroxide nanodisks and nanowires on the silicon substrates. The volume of ammonium hydroxide solution plays a crucial role for controlling the morphology of cadmium hydroxide nanostructures. Cadmium hydroxide nanodisks exhibited very strong and broad emission properties in the cathodoluminescence spectrum. The enhancement in optical properties shall be advantageous in applications for white light-emitting devices.

Plate like Cd (OH)2-CdO Nanocomposite has been synthesized by wet chemical technique in double distilled water. As-synthesized cadmium hydroxide/oxide particles transforms into pure oxide after annealing at 750°C for 2h. As obtained particles are having plate like surface morphology with 15 nm average diameter, while almost spherical as well as rod shaped nanostructures are formed after annealing. The FTIR spectroscopy provides the valuable information and identification of different chemical group/bonds present in the prepared samples. It is found that if we fixed the dopant concentration, then particle size, morphology and band gap energy of prepared nanopowder can be tailored by applying the annealing conditions. Comparative studies of absorption spectra and corresponding band gap energies have been done with thermal treatment. The shift of the optical absorption edge of prepared nanopowder towards lower energies increases its utilization in the visible region specially photo catalytic activity.

Polycrystalline thin films of cadmium hydroxide Cd(OH) 2 with high purity and good adhesion to the substrate were synthesized by an ammonia free chemical bath deposition method. The as-deposited films have a monoclinic crystalline structure with lattice constants a = 6.5768 A, b = 10.2704 A, c = 3.4125 A, α = 90.00°, β = 120.16°, γ = 90.00°, and crystallite size 26.1 ± 0.9 nm. The cubic phase of cadmium oxide with lattice constants a = 4.7155 A and crystallite size of 10.9 ± 0.9 nm was obtained by heating the as-deposited films at 220 °C. The absorption bands in the 3500–3600 cm − 1 range observed in the infrared spectra of the as-deposited films were used to detect the presence Cd(OH) 2 compound. The possible ways to optimize the synthesis of Cd(OH) 2 to be used as precursor for production of chalcogenide films is discussed.

We studied the kinetics of intercalation of a fluorescent probe (rhodamine B (RhB)) during the formation of hierarchal microspheres of cadmium–aluminum layered double hydroxide (CdAlA LDH) and its de-intercalation upon transformation from the LDH phase into the cadmium hydroxide β phase (Cd(OH)2) using a reaction-diffusion framework (RDF) where the hydroxide anions diffuse into an agar gel matrix containing the proper salts–fluorescent probe mixture. In this framework, we achieved the stabilization of the CdAlA LDH, which is known to be thermodynamically unstable and transforms into Cd(OH)2 and Al(OH)3 in a short period. RDF is advantageous as it allows with ease the extraction of the cosynthesized polymorphs and their characterization using X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), solid-state nuclear magnetic resonance (SSNMR), Fourier transform infrared (FT-IR), and energy dispersive X-ray (EDX). The kinetics of inter/de-intercalation is studi...

Cadmium sulfide (CdS) thin film consisting of nanowires over a flat CdS thin film were synthesized by depositing cadmium hydroxide [Cd(OH)2] nanowires (NW) bundles, followed by conversion to sulfide phase by using ion exchange route at room temperature (300 K) based on negative free energy of formation. The influence of post annealing treatment on as-deposited CdS NW films has been studied in the temperature range 423–523 K through the observation of nanowires alignments. The annealing effect on the intrinsic properties have been studied in relation with the crystallites sizes, micro strain, dislocation density and optical band gap of the deposited films. Furthermore, the behavior of inter- and intramolecular hydroxide ion (OH−) has been investigated from FTIR analysis. Additionally, the effects of post annealing on photovoltaic device performance has been scrutinized and the obtained results were correlated with structural and optical properties.

We use the reaction–diffusion framework (RDF) to study the kinetics of formation of hierarchical microstructures of cadmium–aluminum layered double hydroxide (CdAlCl LDH), its particle size distribution, and its polymorphic transformation to brucite-like cadmium hydroxide (β-Cd(OH)2). The system exhibits the evolution of two successive bands separated by a sharp interface, a leading one that constitutes the yellow CdAlCl LDH followed by the white brucite band. We show that by using the RDF we can manipulate the size distribution of the particles within the LDH band along the tubular reactor. The spatiotemporal dynamics of these bands provides a simple means to study the kinetics of formation of the LDH and its polymorphic transformation as a function of the cationic ratio, hence predicting its stability. Consequently, the relative rate constants and the Avrami exponents are calculated and are shown to exhibit a linear correlation with the cationic ratio. The collapse of the LDH microstructures into nano-spheroids of β-Cd(OH)2 is visualized using scanning electron microscopy at the LDH–brucite interface.

Even though nanostructures possess large surface to volume ratio compared to their thin film counterpart, the complicated procedure that demands for the deposition on a substrate kept them back foot in device fabrication techniques. In this work, a honey comb like cadmium sulfide (CdS) thin films nanostructure are deposited on glass substrates using simple chemical bath deposition technique at 65 °C. Energy band gaps, film thickness and shell size of the honey comb nanostructures are successfully controlled using tin (Sn) doping and number of shells per unit area is found to be maximum for 5% Sn doped (in the reaction mixture) sample. X-ray diffraction and optical absorption analysis showed that cadmium sulfide and cadmium hydroxide coexist in the samples. TEM measurements showed that CdS nanostructures are embedded in cadmium hydroxide just like “plum pudding”. Persistent photoconductivity measurements of the samples are also carried out. The decay constants found to be increased with increases in Sn doping.

Controlling self-organization in precipitation reactions has received growing attention in the efforts of engineering highly ordered spatial structures. Experiments have been successful in regulating the band patterns of the Liesegang phenomenon on various scales. Herein, we show that by adjusting the composition of the hydrogel medium, we can switch the final pattern between the classical band structure and the rare precipitate spots with hexagonal symmetry. The accompanying modeling study reveals that besides the modification of gel property, tuning of the time scale of diffusional spreading of hydroxide ions with respect to that of the phase separation drives the mode selection between one-dimensional band and two-dimensional spot patterns.

Cadmium sulfide thin film nanostructures with various surface morphologies were synthesized using chemical bath deposition method (CBD) by varying bath temperature. Samples deposited at room temperature shows surface morphology similar to ‘seaweed’ pattern that crystallized in cubic structure, whereas those deposited at higher temperatures exhibit ‘honeycomb’ like surface pattern with hexagonal crystal structure. HRTEM images of the honeycomb structure shows that, nanowalls consist of CdS nanoparticles embedded with cadmium hydroxide just like ‘plum in pudding’. An improvement in conductivity and photosensitivity observed with increase in bath temperature. Photoluminescence measurements show that there are five emission peaks falls in green, red and infrared bands. The intensity of photoluminescence emission in the green band region found to be increased on thin films that deposited at elevated temperatures. Unique honeycomb like structures observed at 65 °C, shows comparatively high performance in structural and optoelectronic properties give it a slight edge in optoelectronic application.