Simple Thermal Decomposition Research Articles

Fabrication of a Ti/TiO2/NiO electrode for electrocatalytic nitrite removal

Ti/TiO2/NiO (Ti/TNO) electrode used for electrocatalytic oxidation of nitrite was fabricated by a simple thermal decomposition method in this work. The influences of calcination temperature on crystal phase and morphology of Ti/TNO composite were explored by XRD and TEM. After being calcined at 700°C, NiO grains are closely surrounded by TiO2 grains, in which TiO2 acts as an adhesion agent to fix the NiO grains on the Ti plate. The relative contents of Ni(III) and Ti(III) species were found increase due to the close heterojunction between NiO and TiO2, which reduces the impedance and improves the electrocatalytic activity of Ti/TNO. Ti/TNO-350-700 not only exhibits as high activity as those of Ti/TNO-350 and Ti/TNO-700 for electrocatalytic removal of nitrite contaminant, but also owns a superior electrocatalytic stability, which is more than 30 times and 2.5 times longer than those of Ti/TNO-350 and Ti/TNO-700, respectively.

Highly Selective Aerobic Oxidation of 5‐Hydroxymethyl Furfural into 2,5‐Diformylfuran over Mn–Co Binary Oxides

AbstractA series of Mn−Co binary oxides were prepared by a simple thermal decomposition procedure and evaluated for the aerobic oxidation of 5‐hydroxymethylfurfural (HMF) into 2,5‐diformylfuran (DFF). Investigation of the effects of metal amounts and calcination temperatures of the prepared catalysts revealed that the Mn−Co binary oxide with a Mn/Co molar ratio of 1/1 showed the best catalytic performance yielding 42.6 % HMF conversion along with 98 % selectivity to DFF after 2 h of reaction. The as‐prepared catalysts were characterized by nitrogen physisorption, X‐ray powder diffraction (XRD), hydrogen temperature‐programmed reduction (H2‐TPR) and X‐ray photoelectron spectroscopy (XPS). These results indicated that the Mn−Co binary oxides could increase the Mn4+/Mn3+ atomic ratio and the exposed lattice oxygen content on the surface, thus accelerating the HMF oxidation into DFF. Furthermore, the Mn−Co binary oxides proved to be reusable in five consecutive reaction runs without significant loss of activity.

Synthesis and Structural Characterization of CdFe2O4 Nanostructures

The synthesis of CdFe2O4 nanoparticles has been achieved by a simple thermal decomposition method from the inorganic precursor, [CdFe2(cin)3(N2H[Formula: see text]], which was obtained by a simple precipitation method from the corresponding metal salts, cinnamic acid and hydrazine hydrate. The precursor was characterized by hydrazine and metal analyses, infrared spectral analysis and thermo gravimetric analysis. On appropriate annealing, [CdFe2(cin)3(N2H[Formula: see text]] yielded CdFe2O4 nanoparticles. The XRD studies showed that the crystallite size of the particles was 13[Formula: see text]nm. The results of HRTEM studies also agreed well with those of XRD. SAED pattern of the sample established the polycrystalline nature of the nanoparticles. SEM images displayed a random distribution of grains in the sample.

Synthesis and characterization of $$\hbox {BaNiO}_{3}$$ BaNiO 3 using a solid-state thermal decomposition method and the preparation of its stable aqueous suspension

In the present study, the preparation of \(\hbox {BaNiO}_{3}\) nano-oxide is reported via simple solid-state thermal decomposition of \([\hbox {Ba(en)}_{4}][\hbox {Ni(H}_{2}\hbox {O})_{2}\hbox {(NCS)}_{4}]\) precursor complex for the first time. As-prepared nano-oxide was coated by citric acid to form a stable aqueous magnetic suspension. The precursor complex was characterized by conductivity measurements, ultra violet–visible spectroscopy, elemental analysis and Fourier transform infrared spectroscopy. The composition of the perovskite was confirmed by energy-dispersive X-ray spectroscopy analysis and the hexagonal structure was supported by powder X-ray diffraction. In addition, monotonous morphology of the nano-oxide was illustrated by field-emission scanning electron microscopy. Superparamagneticity of the nanoparticles were detected using a vibrating sample magnetometer. Finally, the hydrodynamic size as well as the zeta potential of the pristine and surface-treated \(\hbox {BaNiO}_{3}\) nano-oxide were measured in deionized water via a dynamic light scattering analyzer and they were compared. Results show the excellent stability of the surface-modified magnetic oxide compared to the pristine.

Structural, optical and dielectric investigation of CdFe2O4 nanoparticles

A simple thermal decomposition technique has been executed for the synthesis of cadmium ferrite (CdFe2O4) nanoparticles. With the help of x-ray diffraction; scanning electron microscopy, energy-dispersive x-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy the prepared nanoparticles were identified. The crystal size of the average particles aggregated and was found approximately to be 10–14 nm by means of XRD studies. However, the results of high-resolution transmission electron microscopy (HR-TEM) investigation ensured distinguished nanoparticles, and also the polycrystalline nature of those nanoparticles was confirmed by selected area diffraction (SAED) patterns. The scanning electron microscopy (SEM) images explored a random distribution of grains within the sample. Thin film surface topology of roughness and surface current measurement were studied by atomic force microscopy (TP-AFM, C-AFM). Hence, from the ultraviolet–visible (UV) spectroscopic absorption illustrated significant optical properties. Moreover, the optical energy band gap (Eg) of CdFe2O4 nanoparticle was determined to be 1.74 eV. By studying the variation of dielectric constant and dielectric loss with respect to frequency, the CdFe2O4 nanoparticles electrical properties were analyzed. Analysis in the real and imaginary part of impedance explained their frequency and temperature dependence of the CdFe2O4 nanoparticles. The traditional solution-phase organometallic approach provides an effective way to synthesize high quality hydrophobic semiconductor-CdFe2O4 nanoparticles. Our simple, cost-effective approach is quite general, which is applicable to other nanomaterials, and it utilizes the currently mature in Nano-chemistry. The nanocomposite assemblies’ exhibit strong anisotropic optical and electrical properties are open up new possibilities in remarkable applications for optoelectronics in the near future.

Synthesis of NiS/carbon composites as anodes for high-performance sodium-ion batteries

We demonstrate a general solid-state synthesis of nickel sulfide (NiS) and carbon-based composites (NiS/C) via simple thermal decomposition of nickel dibutyldithiocarbamate (C18H36N2NiS4) under ambient atmosphere, which can be applied to various carbon-based materials such as 2D graphene nanosheets (GNSs), 1D carbon nanotubes (CNTs), and 0D carbon black (CB). When used as anode materials for sodium-ion batteries (SIBs), the as-prepared NiS/C composites demonstrate excellent sodium storage properties including superior cycle stability and rate capability, delivering reversible capacities of 483 (for NiS/GNSs), 394 (for NiS/CNTs), and 413 mAh/g (for NiS/CB) at a current density of 200 mA/g after 100 cycles, respectively, which are much higher than that of the bare NiS counterpart (136 mAh/g at 200 mA/g after 100 cycles). Moreover, reversible capacities of 372 mAh/g for NiS/GNSs, 331 mAh/g for NiS/CNTs, and 317 mAh/g for NiS/CB are realized at a high rate of 2 A/g. The excellent electrochemical performance can be attributed to the introduction of the carbon-based materials, which not only serve as efficient buffering matrixes to tolerate the volume changes of NiS upon sodiation/desodiation but also improve the electrode conductivity. More importantly, this work provides a straightforward and general synthetic approach for designing various NiS/C composites as high-performance anodes for electrochemical energy storage.

Synthesis, characterization and investigation of the electrochemical hydrogen storage properties of CuO–CeO2 nanocomposites synthesized by green method

Pure CuO–CeO2 nanocomposites were synthesized by simple thermal decomposition method in presence of various Cu salts as a copper source and fructose as a green capping agent. In this study, the effect of various parameters such as the type of copper sources, temperature and time of reaction on the morphology and the particles size were studied. The products were characterized via X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), N2 adsorption (BET), vibrating sample magnetometer (VSM), and infrared spectrum (FT-IR). The optical property of the nanocomposite was examined via UV–vis (DRS) spectroscopy and the band gap was calculated to 3 eV. Also, the hydrogen storage capacity of CuO–CeO2 nanocomposites and CeO2 nanoparticles were investigated via chronopotentiometry method for the first time. The discharge capacity of CeO2 nanoparticles and CuO–CeO2 nanocomposites in 1 mA current and 20 cycles obtained 2150 and 2450 mAh/g, respectively.

Facile synthesis of magnetic Co nanofoam by low‐temperature thermal decomposition of Co glycerolate

Fine metal cobalt (Co) nanofoam was prepared via simple thermal decomposition of amorphous non-stoichiometric Co glycerolate under 50 vol% H2/50 vol% N2 atmosphere at 450°C. The nanofoam was characterised by X-ray diffraction, scanning electron microscope/energy dispersive spectroscopy and its magnetic properties were investigated by SQUID magnetometer. This magnetic nanofoam consisted of slightly sintered Co nanocrystals; their average size was 30 nm.

Zinc oxide nanoparticles: solvent-free synthesis, characterization and application as heterogeneous nanocatalyst for photodegradation of dye from aqueous phase

In present study, for the first time, ZnO nanoparticles have been synthesized via a simple, novel, solvent and template free solid-state thermal decomposition of the mixed Zn(NO3)·6H2O and cochineal powders as a novel starting reagent at 600 °C for 3 h. The as-prepared product was analyzed by XRD, EDS, SEM, TEM, FT-IR and DRS. Besides, the effect of cochineal powder on the morphology and particle size of ZnO nanoparticles was investigated. The results exhibited that cochineal powder prevents the sintering of nanoparticles and leads to formation of uniform particles. Moreover, the efficiency of ZnO nanoparticles as a photocatalyst for the decolorization of methylene orange (MO) has been evaluated and 90% degradation of MO was obtained after 120 min.

Multilayered Electride Ca2N Electrode via Compression Molding Fabrication for Sodium Ion Batteries.

Pursuing for novel electrode materials is significant for the progress of sodium ion batteries (SIBs). Here, a multilayered electride prepared by simple thermal decomposition of solid Ca3N2, namely Ca2N, is introduced as a new anode material of SIBs for the first time, and a compression molding electrode fabricated by pressing Ca2N powder into nickel foam is applied to protect Ca2N from trace moisture and oxygen. The as-prepared electrode delivers an initial discharge capacity of 1110.5 mAh g-1 and a reversible discharge capacity of ∼320 mAh g-1. These results suggest that Ca2N has a great potential for sodium ion batteries.

The enhanced MR performance of dimorphic MR suspensions containing either magnetic rods or their non-magnetic analogs

A co-precipitation method was used to prepare non-magnetic rod-like ferrous oxalate dihydrate (Fe2CO4 · 2H2O) particles that were further turned into iron oxide (Fe3O4) magnetic rod-like particles. A simple precursor-assisted thermal decomposition technique enabled the preservation of the morphology and size of the precursor ferrous oxalate dihydrate particles, thus allowing their magnetic analogs to be obtained. Both types of rod-like particles were used as an additive together with spherical carbonyl iron (CI) particles in novel dimorphic magnetorheological (MR) suspensions. Controlled shear rate mode experiments were performed using a rotational rheometer with a source of an external magnetic field in order to investigate their MR behavior. Moreover, the properties of the novel prepared dimorphic MR (DMR) suspensions were compared with conventional MR suspensions based on spherical CI microparticles. It was found that the DMR suspensions exhibit enhanced MR performance as well as enhanced sedimentation stability in comparison with the MR suspension based on pure CI. The dimorphic suspensions containing magnetic rod-like additives further exhibited significant MR hardening at low shear rates. The properties of CI-based suspensions can be thus optimized by using various additive substances.

Pd2Ga-Based Colloids as Highly Active Catalysts for the Hydrogenation of CO2 to Methanol

Colloidal Pd2Ga-based catalysts are shown to catalyze efficiently the hydrogenation of CO2 to methanol. The catalysts are produced by the simple thermal decomposition of Pd(II) acetate in the presence of Ga(III) stearate, which leads to Pd0 nanoparticles (ca. 3 nm), and the subsequent Pd-mediated reduction of Ga(III) species at temperatures ranging from 210 to 290 °C. The resulting colloidal Pd2Ga-based catalysts are applied in the liquid-phase hydrogenation of carbon dioxide to methanol at high pressure (50 bar). The intrinsic activity is around 2-fold higher than that obtained for the commercial Cu-ZnO-Al2O3 (60.3 and 37.2 × 10–9 molMeOH m–2 s–1), respectively, and 4-fold higher on a Cu or Pd molar basis (3330 and 910 μmol mmolPd or Cu–1 h–1). Detailed characterization data (HR-TEM, STEM/EDX, XPS, and XRD) indicate that the catalyst contains Pd2Ga nanoparticles, of average diameters 5–6 nm, associated with a network of amorphous Ga2O3 species. The proportion of this Ga2O3 phase can be easily tuned by ad...

Mn-Doped In2O3 Nanoparticles: a Simple Synthesis and Room-Temperature Ferromagnetism

In this research, Mn-doped In2O3 nanoparticles were successfully synthesized by a simple thermal decomposition method using indium acetate and manganese acetate tetrahydrate as the starting materials. The precursor was characterized by thermal gravimetric analysis (TGA) and differential thermal analysis (DTA) to obtain the thermal decomposition and crystallization temperature. The precursor was calcined at 500–600∘C in air for 2 h to obtain nanoparticles of In2O3 and Mn-doped In2O3. The phase composition of calcined samples was studied by X-ray diffraction (XRD). The XRD results confirmed the formation of In2O3 phase with cubic structure. The particle sizes of the samples were found to be 12–22 nm as evaluated by the X-ray line broadening method. The corresponding selected area electron diffraction analysis further confirmed the formation of the cubic structure of In2O3 without any impurity phases. The optical properties of the samples were investigated by optical absorption. The estimated band gap of the samples was in the range of 3.30–3.45 eV. X-ray photoelectron spectroscopy was performed and played an important role to confirm and understand in terms of qualitative In and Mn oxidation states causing a ferromagnetic properties in the Mn-doped In2O3 sample. Room-temperature ferromagnetism was investigated by a vibrating sample magnetometer. The undoped samples exhibit a diamagnetic behavior, whereas the Mn-doped In2O3 samples are ferromagnetic, having the magnetizations of 0.25–0.62 memu/g at 15 kOe. Successful synthesis of Mn-doped nanoparticles with room-temperature ferromagnetism was of great importance in both technological and theoretical aspects.

FeCo Alloy Nanoparticles Confined in Carbon Layers as High-activity and Robust Cathode Catalyst for Zn-Air Battery

Highly electrocatalytic activity and strong stability towards both oxygen evolution (OER) and oxygen reduction reaction (ORR) have been regarded as the critical factors in widespread application for the renewable energy technologies. It still remains a huge challenge for developing bifunctional catalysts with low cost, efficiently electrocatalytic activity and strong stability. In this paper, FeCo alloy nanoparticles embedded in nitrogen-doped carbon are synthesized through a simple thermal decomposition of Co-Fe Prussian Blue Analogue (Co-Fe PBA) in Ar atmosphere, during which the organic ligand of CN− in Co-Fe PBA provides both carbon and nitrogen sources for forming nitrogen-doped carbon and FeCo alloy nanoparticles were formed, and thus producing a core-shell structure (FeCo@NC). According to a set of electrochemical tests, the obtained FeCo@NC can function as a Janus to drive OER and ORR with desirable activities and stabilities in alkaline media. Specifically, the FeCo@NC presents an onset-potential of 1.45V, a potential of 1.49V at 10mAcm−2, a Tafel slope of 62mVdec−1 as OER catalyst, and an onset potential of 0.94V, a half-wave potential of 0.8V as ORR catalyst. The performance is comparable to those of precious metal based electrocatalysts, making it possible for potential application in the renewable energy devices, especially Zn-air battery.

A novel hierarchical 3D N-Co-CNT@NG nanocomposite electrode for non-enzymatic glucose and hydrogen peroxide sensing applications

A novel 3D nanocomposite of nitrogen doped Co-CNTs over graphene sheets (3D N-Co-CNT@NG) have been successfully fabricated via a simple, scalable and one-step thermal decomposition method. This 3D hierarchical nanostructure provides an admirable conductive network for effective charge transfer and avoids the agglomeration of NG matrices, which examine direct as well as non-enzymatic responses to glucose oxidation and H2O2 reduction at a low potential. The novel electrode showed excellent electrochemical performance towards glucose oxidation, with high sensitivity of 9.05μAcm−2mM−1, a wide linear range from 0.025 to 10.83mM, and a detection limit of 100nM with a fast response time of less than 3s. Furthermore, non-enzymatic H2O2 sensors based on the 3D N-Co-CNT@NG electrode exhibited high sensitivity (28.66μAmM−1cm−2), wide linear range (2.0–7449μM), low detection limit of 2.0μM (S/N=3), excellent selectivity, decent reproducibility and long term stability. Such outstanding electrochemical performance can be endorsed to the large electroactive surface area, unique porous architecture, highly conductive networks, and synergistic interaction between N-Co-CNTs and nitrogen doped graphene (NG) in the novel 3D nanocomposite. This facile, cost-effective, sensitive, and selective glucose as well as H2O2 sensors are also proven to be appropriate for the detection of glucose as well as H2O2 in human serum.

Particle size, spin wave and surface effects on magnetic properties of MgFe2O4 nanoparticles

Magnesium ferrite, MgFe2O4, nanoparticles with a mean diameter varying from ∼6 to ∼17nm were successfully synthesized using a simple thermal decomposition method at different annealing temperatures ranging in between 400 and 600°C. Pure spinel ferrite nanoparticles were obtained at temperatures lower than 500°C, while the presence of hematite (α-Fe2O3) impurities was observed at higher temperatures. Single-phase samples show a superparamagnetic behavior at 300K, the saturation magnetization (Ms) becoming larger with the increase of particles size. The temperature dependence of Ms was explained in terms of surface spin-canting as well as spin wave excitations in the core. Using a modified Bloch law, [Ms(T)=Ms(0)(1−βTα)], we observed a size dependent behavior of the Bloch constant β and the exponent α, whose values increase and decrease, respectively, as the particle size reduces.

Shape and size controlled synthesis of uniform iron oxide nanocrystals through new non-hydrolytic routes

New, non-hydrolytic routes to synthesize highly crystalline iron oxide nanocrystals (8–40 nm, magnetite) are described in this report whereby particle size and morphology were precisely controlled through reactant (precursor, e.g. (FeO(OH)) ratios, co-surfactant and organic additive, and/or reaction time. Particle size, with high monodispersivity (<10%), is demonstrated to be a function of precursor concentrations and through the addition of different cosurfactants and/or additives, cubic, octahedral, potato-like, and flower-like iron oxide nanocrystals can be reproducibly synthesized through simple one-pot thermal decomposition methods. High resolution transmission electron microscope, x-ray diffraction, and superconducting quantum interference device were used to characterize the size, structure and magnetic properties of the resulting nanocrystals. For aqueous applications, materials synthesized/purified in organic solvents are broadly water dispersible through a variety of phase (aqueous) transfer method(s).

A Layered Delta-MnO2 Nanoflake Cathode with High Zinc-Storage Capacities for Eco-Friendly Battery Applications

This study reports the use of a layered-type birnessite δ-MnO2 nano-flake cathode for eco-friendly zinc-ion battery (ZIB) applications. The present δ-MnO2 was prepared via the simple low temperature thermal decomposition of KMnO4. The X-ray diffraction (XRD) pattern of the samples was well indexed to the δ-MnO2 phase. Field emission SEM and TEM images of the δ-MnO2 revealed flake-like morphologies with an average diameter of 200 nm. The electrochemical properties, investigated by cyclic voltammetry and constant current charge-discharge measurements, revealed that the nano-flake cathode exhibited first discharge capacity of 122 mAh g-1 under a high current density of 83 mA g-1 versus zinc. The discharge capacity thereafter increased until it reached 252 mAh g-1 in the fourth cycle. On the hundredth cycle, the electrode registered a discharge capacity of 112 mAh g-1. Coulombic efficiencies of nearly 100% were maintained on prolonged cycling and thereby indicate the long cycle stability of the δ-MnO2. Besides, the realization of specific capacities of 92 and 30 mAh/g at high current densities of 666 and 1333 mA/g, respectively, clearly demonstrates the decent rate capabilities of δ -MnO2 nano-flake cathode. These results may facilitate the utilization of layered-type birnessite δ-MnO2 in ZIB applications.

Novel and solvent-free cochineal-assisted synthesis of Ag–Al2O3 nanocomposites via solid-state thermal decomposition route: characterization and photocatalytic activity assessment

Herein, silver–alumina nanocomposites have been synthesized via simple, novel, solvent-free and template-less solid-state thermal decomposition using cochineal powder as novel starting reagent for the first time. AgNO3 and Al(OH)3 were utilized as silver and aluminum source, respectively. The prepared Ag–Al2O3 nanostructures were characterized extensively by means of X-ray diffraction, energy-dispersive X-ray analysis, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and UV–Vis spectroscopy. Effect of reaction time, temperature and cochineal powder on morphology and particle size of prepared products was investigated. The results exhibited that in presence of cochineal powder, as-prepared nanostructures show very high degree of purity and uniformity. In other words, because of remarkable antioxidant properties of cochineal, it prevents silver nanoparticles from sintering and oxidizing. The silver–alumina nanocomposite were evaluated as photocatalyst for the Rhodamine B degradation using visible light irradiation and showed significant photocatalytic efficiency.

Insights into secondary reactions occurring during atmospheric ablation of micrometeoroids

Ablation of micrometeoroids during atmospheric entry yields volatile gases such as water, carbon dioxide, and sulfur dioxide, capable of altering atmospheric chemistry and hence the climate and habitability of the planetary surface. While laboratory experiments have revealed the yields of these gases during laboratory simulations of ablation, the reactions responsible for the generation of these gases have remained unclear, with a typical assumption being that species simply undergo thermal decomposition without engaging in more complex chemistry. Here, pyrolysis–Fourier transform infrared spectroscopy reveals that mixtures of meteorite-relevant materials undergo secondary reactions during simulated ablation, with organic matter capable of taking part in carbothermic reduction of iron oxides and sulfates, resulting in yields of volatile gases that differ from those predicted by simple thermal decomposition. Sulfates are most susceptible to carbothermic reduction, producing greater yields of sulfur dioxide and carbon dioxide at lower temperatures than would be expected from simple thermal decomposition, even when mixed with meteoritically relevant abundances of low-reactivity Type IV kerogen. Iron oxides were less susceptible, with elevated yields of water, carbon dioxide, and carbon monoxide only occurring when mixed with high abundances of more reactive Type III kerogen. We use these insights to reinterpret previous ablation simulation experiments and to predict the reactions capable of occurring during ablation of carbonaceous micrometeoroids in atmospheres of different compositions.