IR@CECRI
Not a member yet
2644 research outputs found
Sort by
Effect of ecofriendly sealing coat against corrosion protection of steel rebars in concrete
No full textPhosphating is one of the most important chemical conversion treatments for steel, mainly to improve
corrosion resistance and paint adhesion and as an absorbing layer for waxes, oils, lacquers, etc.
However, phosphate coating are crystalline and porous and need a sealing treatment after
phosphating. Chromate sealing is a well known practice, and due to its toxicity, development of an
ecofriendly sealing treatment is very essential. This paper focuses on the effect of zinc phosphate
chemical conversion coating with the addition of nano-SiO2 to protect the mild steel rebars against
corrosion in chloride contaminated concrete. The coated surfaces were characterised by scanning
electron microscopy and X-ray diffraction. Corrosion resistances of coated and uncoated rebars were
evaluated by anodic polarisation, linear polarisation resistance, Tafel and alternating current impedance
spectroscopy and cyclic polarisation technique. The results indicated that the coated rebars have
considerably reduced the corrosion rate even in the presence of 3% chloride environment
Self-assembled wire-like and honeycomb-like osmium nanoclusters (NCs) in DNA with pronounced catalytic and SERS activities
No full textA new route to the formation of ultra-small Os nanoparticles (NPs) in DNA is reported. The Os NPs that are
initially formed are self-assembled together to form Os nanoclusters (NCs) which have wire-like and
honeycomb-like morphologies. The synthesis was carried out within a minute using microwave heating
by the reaction of Os salt with ethanol. The size of the individual Os NPs varies between 1 and 3 nm and
the synthesized particles are stabilized in DNA. The stable Os NCs showed a coupled SPR band near 600
nm in the visible region, which is useful for using the material as a potential SERS substrate. The SERS
study was carried out using methylene blue (MB) as a model SERS probe molecule and the observed EF
value is �107, which is much higher compared to a recent report for Os NPs. Apart from SERS, the Os
NCs have also been tested in a catalysis reaction. The catalysis reaction was carried out for the first time
for the reduction of organic nitro compounds in the presence of excess NaBH4. The catalytic reaction
rate using Os NCs as a catalyst was found to be superior compared to earlier reports with other metal
NPs, like Au or Ag. The improved catalytic and SERS activities of the Os NCs due to their ultra-small size
with a high surface area might be useful in future in the field of biosensors, biomedicine, nano devices
and other organic catalysis reaction
Electrochemical Synthesis of Magnesium Hexaboride by Molten Salt Technique
No full textThe present work reports electrochemical synthesis of MgB6 from molten salts using the precursor consists of LiF–B2O3–MgCl2.
An attempt has been made to synthesize metastable phase MgB6 crystal by electrolysis method. DTA/TGA studies were made to
determine the eutectic point of the melt and it was found to be around 900∘C. The electrolysis was performed at 900∘C under
argon atmosphere, at current density of 1.5A/cm2.The electrodeposited crystals were examined using XRD, SEM, and XPS. From
the above studies, the electrochemical synthesis method for hypothetical MgB6 from chloro-oxy-fluoride molten salt system is
provided. Mechanism for the formation of magnesium hexaboride is discusse
Synthesis of Nitrogen Doped Carbon and Its Enhanced Electrochemical Activity towards Ascorbic Acid Electrooxidation
No full textNitrogen doped carbon, synthesized by a novel way of carbonizing polyaniline in an inert atmosphere at a constant temperature of
800∘C, exhibits several unique features.The carbon: nitrogen ratio is found to increase with the treatment duration up to 120 minutes
and a mass reduction of 60 wt% is observed with an interesting observation of the retention of the bulk polymer morphology,
surprisingly, even after the carbonization process. The electrochemical activity evaluated with potassium hexacyanoferrate and
hexamine ruthenium redox systems at a regular time interval helps to tune the catalytic activity. This type of nitrogen doped carbon
prepared from polyaniline base exhibits excellent electrocatalytic activity as illustrated by the oxidation of ascorbic acid in neutral
mediu
Faceted shape-drive cathode particles using mixed hydroxy-carbonate precursor for mesocarbon microbeads versus LiNi1/3Mn1/3Co1/3O2 Li-ion pouch cell
No full textUsing a mixed hydroxy-carbonate (MHC) precursor, homogeneous LiNi1/3Mn1/3Co1/3O2 phase synthesized
through a facile route yielded well dispersed, faceted, edge-blunted polyhedral particles
(w200 nm). These cathode particles revealed high degree of hexagonal ordering favorable for impressive
electrochemical performance viz., high capacity 187 mAh g�1 in Li vs LiNi1/3Mn1/3Co1/3O2 cell, not
fortuitously. Rather, can be clearly attributed to edge-blunted cathode particles that may facilitate
enhanced charge mobility mimicking a process akin to corona discharge predominantly in charge
concentrated regions which contrasts to moderate capacity from spherical particles explainable under
the ambit of shape-drive hither to unknown. Li-ion pouch cell (w500 mAh) fabricated with this activity
enhanced cathode quite rugged enough to endure loads (0.12 Wh, 1.1 Wh), as-demonstrated
In situ carbon coated LiFePO4/C microrods with improved lithium intercalation behavior
No full textLiFePO4/C microrods consisting of building blocks of interconnected nanoparticles surrounded by a thin
and amorphous coating of carbon have been prepared by a customized hydrothermal method.
Appreciable discharge capacity values of 168 mA h g�1 at 0.1 C and 130 mA h g�1 at 5 C rates have
been exhibited by the currently synthesized LiFePO4/C cathode. The study enumerates the feasibility
of exploiting the hydrothermal method to prepare an in situ carbon coated LiFePO4/C compound
with tunable morphological properties and desirable electrochemical properties observed for up to
100 cycles at a 5 C rat
Electric field induced transformation of carbon nanotube to graphene nanoribbons using Nafion as a solid polymer electrolyte
No full textWe report a remarkable transformation of multiwalled carbon nanotubes (MWCNTs, average
diameter 40 nm) to graphene nanoribbons (GNRs) in response to a field gradient of 25 V/cm, in
a sandwich configuration using a solid state proton conducting polymer electrolyte like a thin
perfluorosulphonated membrane, Nafion. In response to the application of a constant voltage for
a sustained period of about 24 h at both room temperature and elevated temperatures, an
interesting transformation of MWCNTs to GNRs has been observed with reasonable yield. GNRs
prepared by this way are believed to be better for energy storage applications due to their
enhanced surface area with more active smooth edge planes. Moreover, possible morphological
changes in CNTs under electric field can impact on the performance and long term stability of
devices that use CNTs in their electronic circuitr
Formation of shape-selective magnetic cobalt oxide nanowires: environmental application in catalysis studies
No full textA new route for the formation of shape-selective CoO nanowires has been developed using a simple
microwave (MW) heating method. The reduction of Co(II) ions was done using a new reducing agent
alkaline 2,7-dihydroxy naphthalene (2,7-DHN) in cetyltrimethylammonium bromide (CTAB) micellar media.
The reaction mixture was irradiated using MW for a total time of 6 min. The process exclusively generates
CoO nanowires of different lengths and having diameter y5 ¡ 2 nmto 15 ¡ 2 nm range just by tuning
the metal-ion-to-surfactant molar ratios and changing the other reaction parameters. Magnetization
measurements indicate that there is no observable coercivity for the short nanowires, but the coercivity
increases as the length of the nanowires increases although the magnetic moment values at the maximum
applied magnetic field of 2 T decreased with an increase in the length of the nanowires. The synthesized
CoO nanowires are found to serve as an effective catalyst for the mineralization of several organic dye
molecules in the presence of NaBH4 in a short reaction time. The process assists the room temperature
mineralization of the dyes and provides a cleanup measure of dye contaminated water bodies even in the
presence or in the absence of light. The yield of the CoO nanowires with uniform shapes is found to be
significantly high (.95%) and the nanowires are stable for more than a month under ambient conditions.
The proposed synthesis method is efficient, straightforward, reproducible, and robust. Other than in
catalysis, the cobalt oxide nanomaterials can also be applied for making pigments, lithium-ion battery
materials, solid state sensors, or as anisotropy source for magnetic recordin
Pd–TiO2/C as a methanol tolerant catalyst for oxygen reduction reaction in alkaline medium
No full textTiO2 on carbon was prepared by sol–gelmethod. Pd supported on TiO2–C comprising Pd and Ti in varying atomic
ratios namely, 1:1, 2:1 and 3:1 was prepared and characterized by X-ray diffraction and Transmission electron
microscopy techniques. The electrocatalytic activity for oxygen reduction reaction in aqueous 0.1 M KOH solution
containing methanol was characterized by rotating disk electrode. Catalytic activity of Pd–TiO2(3:1)/C for
ORR and methanol tolerance was found to be superior in relation to Pd/
PROCESS ON DEVELOPMENT OF ANTICORROSIVE COATING SYSYEM WITH POLYANILINE USEFUL FOR CORROSION PROTECTION OF STEEL REINFORCEMENT IN CONCRETE STRUCTURES
No full textThis provides an anticorrosive coating system containing polyaniline for corrosion protection of steel reinforcements in concrete structures. The developed coating system is found to have good adherence to the substrate and offers high corrosion resistance in concrete environment. The corrosion resistant property of the coating has been evaluated by immersion test, potential measurements, impedance test in simulated concrete environment i.e. cement extract and also by various accelerated tests such as applied voltage test, anodic polarization studies and impressed voltage test in concrete