Papers by Keyword: Hydrazine

Abstract: Atomic layer deposition (ALD) was used to grow titanium nitride (TiN) on SiO₂ with TiCl₄ and N₂H₄. X-ray photoelectron spectroscopy (XPS) and ellipsometry were used to characterize film growth. A hydrogen-terminated Si (Si-H) surface was used as a reference to understand the reaction steps on SPM cleaned SiO₂. The growth rate of TiN at 573 K doubled on Si-H compared to SiO₂ because of the formation of Si-N bonds. When the temperature was raised to 623 K, O transferred from Ti to Si to form Si-N when exposed to N₂H₄. Oxygen and Ti could be removed at 623 K by TiCl₄ producing volatile species. The added surface reactions reduce the Cl in the film below detection limits.

Abstract: Hydrous hydrazine is a promising hydrogen carrier material because of its high content of hydrogen (8.0 wt.%) and easy recharging as a liquid. Amorphous Ni_8.1Co_1.0Pt_0.9/Ce₂O₃ nanoparticles with low precious-metal content were synthesized by a facile co-reduction method at room temperature under ambient atmosphere. The increased degree of amorphization was attributed to the introduction of Ce₂O₃. The resultant Ni_8.1Co_1.0Pt_0.9/Ce₂O₃ nanocomposite was employed as an efficient nanocatalyst towards the decomposition of hydrous hydrazine to H₂, and exhibited excellent catalytic activity and 100% H₂ selectivity. Turnover frequency (TOF) value catalyzed by amorphous Ni_8.1Co_1.0Pt_0.9/Ce₂O₃ is 93.75 h^-1, which is much higher than Ni_8.1Co_1.0Pt_0.9 (4.39 h^-1) at 298 K. The development of the improved catalytic performance and low-cost catalyst with amorphous structure is believed to strongly promote the practical application of hydrous hydrazine as a hydrogen storage material.

Abstract: In Situ gas phase passivation methods can enable new channel materials. Toward this end pure anhydrous HOOH and H2NNH2 membrane gas delivery methods were developed. Implementation led to Si-OH passivation of InGaAs(001) at 350C and Si-N-H passivation of SiGe(110) at 285C. XPS and initial electrical characterization has been carried out. Feasibility for In Situ dry surface preparation and passivation was demonstrated.

Abstract: The effect of hydrazine, N₂H₄ in the presence of fatty amide as corrosion inhibitor on corrosion of carbon steel in 3.5 wt% NaCl solution was studied by linear polarization resistance method (LPRM) at room temperature and static condition. The specimens’ surface analysis was done using atomic force microscope (AFM). The inhibition efficiency improved to more than 80% when 500, 100 and 2000 ppm of hydrazine were added to the inhibited solution containing 20 ppm fatty amide. The results obtained show that the inhibition effect is increased with increase of hydrazine concentration in inhibited solution. It indicates that hydrazine retards the reduction of oxygen in the corrosion process by reacting with dissolved oxygen in the solution and thus, further it reduces the corrosion rate of carbon steel.

Abstract: In this work the stability of TiN and TiC nanopowders in isopropyl alcohol as well as the fabrication of dense and well adhered thin coatings based on TiN and TiC by electrophoretic deposition (EPD) have been evaluated in terms of zeta potential and mass deposited when hydrazine is added. The surface of TiN and TiC nanoparticles has been modified to improve the dispersion in isopropyl alcohol adding a cationic polymer (polyethylenimine) as dispersant with two different molecular weights. The influence of acidic/basic character of the solvent also has been evaluated in order to reach the most efficient EPD process. It was found that the adsorption of polyethylenimine with higher molecular weight can preserve the homogeneity of TiC coatings. The surface of TiN nanoparticles can be tuned in order to achieve a similar polyethylenimine adsorption which also improves the deposition in basic media.

Abstract: Hydrazine adsorption on Ni(110) surface is studied using density functional theory. Adsorption of hydrazine in its critical conformations (anti, cis, and gauche) on both 0.25 ML and 0.11 ML coverages are investigated. The results reveal that on both coverage, gauche conformations are adsorbed as the most stable conformation. The stable conformation tends to shift to cis as the coverage is reduced. Density of states analysis suggests that d_z²-band of Ni and p_z orbital of hydrazine are responsible for bonding formation between two constituents.

Abstract: Theoretical investigation of co-adsorption process between hydrazine (N₂H₄) and OH^- on Ni(111) is performed using density functional theory. OH^- adsorption mechanisms at various adsorption sites as well as its interaction with hydrazine in various conformations (anti, cis, and gauche) are studied. The stability of OH^- adsorption on nickel surface is significantly influenced by the presence of hydrazine molecule. Among the three conformations of hydrazine, OH^- adsorption on nickel surface doesn't occur in cis conformation. Otherwise, co-adsorption occurs in system with gauche and anti conformation. In anti system, hydrazine conformation is transformed during relaxation process and forms gauche conformation as the most stable configuration of the system.

Abstract: Copper nanoparticles (CuNPs) have been prepared by the reduction of copper chloride in glycerol using hydrazine at ambient conditions. The reduction process takes place under vigorous stirring for 8 h. The formation of CuNPs and size were confirmed by UV/Vis analysis and TEM imaging respectively. The experiment result showed that, 7.062 mM of hydrazine solution and 0.0147 mM of Cu²⁺ solution were needed to synthesize narrow size monodisperseCuNPs.The presence of nanoparticle was found after an induction period of 4 h and further reaction time, complete Cu⁰ state nanoparticle was obtained as deep red wine colour was observed. Stability study of CuNPs showed that the nanoparticles were stable up to 4 days. The particle size of the nanoparticles have been analysed by transmission electron microscopy (TEM) and the average size of CuNPs was in the range 2 to 10 nm.

Abstract: A compound of (1E,2E)-1,2-di (-3-nitrobenzylidene) hydrazine was synthesized under microwave irradiation (500 w), giving high yields of products (93%). Its structure was determined IR, ¹H NMR, MS, elemental analysis and X-ray diffraction. The crystal of the compound is Monoclinic, space group P2(1)/n with a = 6.9611(18), b = 7.823(2), c = 12.999(3) Å, α = 90, β = 105.215(4), γ = 90^o, V= 683.1(3) Å3, Z=4, Dc=1.450g/cm3,μ=0.110 mm-1, F(000)=308, R=0.0401 and wR = 0.1131 for 1273 observed reflection with I>2σ (I). π-π stacking interactions contribute to the stability of the structure.

Abstract: Gold-palladium nanoparticles (AuPd NPs) were prepared on a layer of graphene (GR) film by potentiostatic electrodeposition from a mixture electrolyte of HAuCl₄ and H₂PdCl₄ to fabricate the AuPd NPs/graphene/glass carbon electrode (AuPd/GR/GCE). The synthesized composite has been characterized using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). Electrocatalytic oxidation of hydrazine on the surface of modified electrode was investigated with cyclic voltammetry and chronoamperometry methods, the results showed that the AuPd NPs high catalysis for the electrochemical oxidation of hydrazine and the excellent conductivity of graphene. Electrocatalytic activity of the modified electrode was investigated for the oxidation of hydrazine in 0.1 M phosphate buffer solutions (pH=6.0). Under the optimized conditions, the oxidation current of hydrazine was linear to its concentration in the range of 2185 μM, and the estimated detection limit was 0.2 μM (S/N =3).