Naushad Ahmad

Hydrogen adsorption properties of nano- and microstructures of ZnO

Nanoparticles, microflowers, and microspheres of zinc oxide have been synthesized in a large quantity via solution process at low temperature and were tested for the hydrogen adsorption studies. The experiments were carried out using Sieverts apparatus which resulted in highest hydrogen adsorption value for nanoparticles is ∼1.220 wt%, whereas for microflower composed with thin sheets value reduced (∼1.011wt%) but in case of microspheres composed with nanoparticles having below one wt% (∼0.966 wt%). The FE-SEM and XRD clarify that the obtained products are crystalline with wurtzite phase. Including morphological and crystalline characterization, the surface area of the prepared nano- and microstructures was observed with BET.

Development of poly(urethane-ester)amide from corn oil and their anticorrosive studies

ABSTRACT Corn oil-based poly(urethane-ester)amide was synthesized from corn oil-based fatty amide diol, camphoric acid, and tolylene 2,4-diisocyanate. The structure of corn polyesteramide and corn poly(urethane-ester)amide (CPEA) was confirmed by Fourier transform infrared, 1H NMR, and 13C NMR spectroscopic techniques. CPUEA coatings were made on mild steel strips and their physicomechanical analysis (scratch hardness, impact test, conical mandrel test, and pencil hardness tests) was performed by standard methods. The surface morphology of coatings was observed by scanning electron microscopy and thermal stability was assessed by thermogravimetric analysis/differential scanning calorimetry. Anticorrosion properties of CPUEA were observed in acidic, saline, and tap water medium at room temperature using potentiodynamic polarization technique. The results of CPUEA coatings exhibit good physicomechanical and anticorrosive properties and can find application up to 175°C.

Effect of cobalt doping on structural, optical and redox properties cerium oxide nanoparticles

Cobalt-doped ceria nanoparticles were synthesized using the polyol method under co-precipitation hydrolysis. The structural, morphological, optical and redox properties were observed to investigate the influence of different concentration of cobalt ion doping on the prepared CeO2 nanomaterials in terms of X-ray diffraction, field-emission transmission electron microscopy, thermogravimetric analysis, Fourier-transform infrared spectroscopy, UV/vis absorption spectroscopy and temperature program reduction techniques. The optical band gap energy was calculated from the optical absorption spectra for doped ceria nanoparticles, which have been found to be 2.68, 2.77, and 2.82 eV for the 2, 4, and 7 mol% Co ion-doped CeO2 nanoparticles, respectively. As observed, the band gap energies increases as the doping Co ion concentrations increased, which could be due to significant increased oxygen vacancies with Co doping. The synergistic interaction between Co and CeO2 was the main factor responsible for high catalytic activity of cobalt-doped CeO2 model catalysts.

Influence of copper ion doping on structural, optical and redox properties of CeO2 nanoparticles

In this study, we doped different concentrations of copper ion in CeO2 matrix to investigate the influence of doping concentrations on crystal structure, thermal, optical and redox properties of the as-prepared nanoproducts. X-ray diffraction (XRD) patterns indicate that the doped CeO2 nanoparticles were highly crystalline with dominant (111) texture. No other impurities were observed and Cu ions were homogenously distributed inside the CeO2 lattice. As observed by transmission electron microscopy (TEM) the homogenously distributed nanoparticles were agglomerated with increase doping contents because of decreased crystalinity. The temperature program reduction (TPR) technique was used to examine the redox character of the doped ceria nanoparticles. The Cu ions doped CeO2 were reduced at low temperature indicating the high catalytic activity. The synergistic interaction between Cu and CeO2 was the main factor responsible for high catalytic activity of the Cu doped CeO2 model catalysts. Furthermore, the as-obtained Cu-doped CeO2 nanoparticles revealed superior redox performance in contrast with pure CeO2 prepared by the same route.

Synthesis and Characterization of Poly(urethane-ether azomethine) Fatty Amide Based Corrosion Resistant Coatings from Pongamia glabra Oil: An Eco-Friendly Approach

A novel attempt has been made to incorporate azomethine group in the backbone of polyurethane ether Pongamia oil fatty amide. The overall reaction was carried out in different steps like preparation of N,N-bis(2-hydroxyethyl) Pongamia glabra oil fatty amide, poly(ether fatty amide), and poly(urethane-ether) fatty amide. The hydroxyl terminated Schiff base, ethane 1,2-di(azomethine) bisphenol, reacts with fatty amide diol and is further treated with toluylene 2,4-diisocynate (TDI) to form poly(urethane-ether azomethine) fatty amide (PUEAF). These synthesized resins were characterized by FT IR, 1H NMR, and 13C NMR spectroscopic techniques. Molecular weight of PUEAF resin was measured by gel permeation chromatography (GPC), coating was made on mild steel strips, and evaluating their physicochemical and physicomechanical analysis was carried out by standard methods. The PUEAF25 coating showed highest scratch hardness (2.5 kg), gloss (90) at 45°, pencil hardness (4H), and impact resistance (150 lb/inch). Atomic force microscopy (AFM) and differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA) were used to determine the topography and thermal behavior of PUEAF. Corrosion studies of PUEAF coated mild steel were used in different corrosive media (3.5 wt% HCl, 5 wt% NaCl, and tap water) at room temperature using potentiodynamic polarization technique. The results of this study showed that PUEAF coatings exhibit good physicomechanical, anticorrosive properties and get application up to 180°C.

Modified Polyacrylic Acid-Zinc Composites: Synthesis, Characterization and Biological Activity

Polyacrylic acid (PAA) is an important industrial chemical, which has been extensively applied in various fields, including for several biomedical purposes. In this study, we report the synthesis and modification of this polymer with various phenol imides, such as succinimide, phthalimide and 1,8-naphthalimide. The as-synthesized derivatives were used to prepare polymer metal composites by the reaction with Zn+2. These composites were characterized by using various techniques, including NMR, FT-IR, TGA, SEM and DSC. The as-prepared PAA-based composites were further evaluated for their anti-microbial properties against various pathogens, which include both Gram-positive and Gram-negative bacteria and different fungal strains. The synthesized composites have displayed considerable biocidal properties, ranging from mild to moderate activities against different strains tested.

Thermal decomposition and kinetic studies of solid riboflavin using model-free methods

The thermal stability and decomposition kinetics of riboflavin were investigated by nonisothermal thermogravimetric analysis (TGA) experiments in an inert atmosphere. For kinetic analysis, riboflavin was heated from room temperature to 800 °C with five different heating rates (5,10,15,20 and 30°C min−1). From the thermal decomposition process, it was found that there are two main stages of pyrolysis. In the DTG thermograms, the temperature peaks at maximum weight loss rate changed with varying heating rate. The kinetic parameters of decomposition including apparent activation energy (Ea) and lnA (pre-exponential factor) under an inert atmosphere have been evaluated from the model-free isoconversion methods of Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO) and Friedman over the whole temperature domain. It was found that values of Ea and lnA decrease with increasing conversion (α). The reaction order does not have a significant influence on the process because of the high value of the pre-exponential factor. The apparent activation energy distributions with conversion calculated by these methods ranged between 15.18 and 236.55 kJ mol−1, and varied over a broad range in a complex manner depending on the heating rate.

Impact of Ni Ion-Doping on Structural, Optoelectronic and Redox Properties of CeO 2 Nanoparticles

We have investigated the influence of Ni doping on the physicochemical properties of CeO2 synthesized by a co-precipitation process. As-prepared nanoparticles were characterized by x-ray diffraction pattern (XRD), transmission electron microscopy (TEM), energy dispersive x-ray analysis, thermal analysis, Fourier transform infrared spectra, optical absorption and temperature program reduction techniques. The observed results clearly demonstrate the impact of Ni ion concentration on the crystallinity, optoelectronic and reducibility of CeO2 nanoparticles. XRD results show that the particle size was decreased after increasing the Ni ion-doping concentrations. TEM micrographs exhibited high aggregation in high Ni ion-doping concentration causing the smallest grain size of the materials. The band gap energies increased with decreasing particle size because of the higher oxygen-releasing capacity and stronger interaction between nickel and the CeO2 matrix. The 7% mol Ni-doped CeO2 exhibits low-temperature reduction. Because of excellent optoelectronic and redox properties, magnetically active Ni ion-doped CeO2 nanoparticles can be used for electrochemical biosensors and solid oxide fuel cell catalysts can be potentially extended to other applications.

Effect of organoclay on structure, morphology, thermal behavior and coating performance of Jatropha oil based polyesteramide

Abstract Jatropha oil (JO) is an inedible oil mainly used in biodiesel. We have attempted to prepare a JO-based polyesteramide/clay composite using a one-pot, two-step reaction, for application as a protective coating. The aim of the work is to utilize JO for its value-added application by preparing a JO polyesteramide/clay composite, to investigate the potential of the prepared composite as a protective coating, and also to study the effect of loaded clay on the structure, morphology, thermal stability and coating properties of the composite. The formation of composites was confirmed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and atomic force microscope (AFM) studies. The coating properties were studied by standard physico-mechanical and corrosion resistance tests in corrosive media (3.5 wt% HCl, 3.5 wt% NaCl and tap water). The thermal stability was assessed by differential scanning calorimetry (DSC), thermogravimetric (TGA) and derivative thermogravimetric (DTG) analyses. The coatings showed good physico-mechanical and corrosion resistance performance and can be safely used up to 275°C. The approach paves way towards an alternate value addition to a non-edible oil.

Fabrication, Characterization, and Growth Mechanism of Cobalt Oxide Nanodots to Nanospheres Via Soft Chemical Solution Process

In this study, the authors report a facile synthesis for the formation of nanoscale CoO dots to nanospheres via solution technique at low temperature and characterized in terms of their morphological, structural, compositional, and thermal properties. The morphological characterizations of as-synthesized and annealed CoO structures were done by scanning electron microscopy (SEM) and transmission electron microscopy, which confirmed that synthesized products are very small in size and bears small dots to spheres such as structures. The surface of nanodots is smooth and clean throughout the whole morphology. The crystalline property was analyzed with X-ray diffraction pattern and it reveals that the formed structures exhibit small size and clearly consistent with SEM observation. The compositional and thermal properties of as-synthesized and annealed CoO structures were observed via Fourier transform infrared spectroscopy and Thermogravimetric analysis, which confirmed that synthesized structures are pure CoO and showed good thermal stability. Finally, plausible mechanisms for the formation of CoO nanodots to nanospheres are also discussed.