by cvd method ,hydrothermal method and sol gel method

1. Submitted to: Dr.farid-ud-din
Submitted by : shafaq saba
Roll no: 16361507-034
Course title: Inorganic chemistry-III
Course code: CHEM-307
Semester : spring 2019
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2. Pyrite and its synthesis
h
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3. Contents
 Introduction 04
 Methods of synthesis 05
 Hydrothermal method 06
 Sol gel method 07
 Chemical vapor deposition 10
 Figure no 1 11
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4. Introduction:
 Chemical Formula – FeS2
 Pyrite is an iron sulfide mineral named from the Greek word for 'fire', as it emits sparks when hit
with other metals or minerals.
 Pyrite, formally known as Iron disulfide, is the most abundant naturally occurring of the sulfide
minerals. It has a crystal structure that resembles the fluorite structure. Iron disulfide has a
yellow-brass, metallic luster that is sometimes incorrectly recognized as gold. Due to this
mistaken identity it is often referred to as “fool’s gold”.
 It is non-fluorescent and magnetic after heating.
 Pyrite is also used for commercial production of sulfur dioxide, which is used in the paper
industry as well as in the manufacture of sulfuric acid. Fool’s gold also has applications in jewelry,
mineral detection in radio receivers, and photovoltaics.
 Iron Disulfide (FeS2) is a semiconductor with a suitable energy band gap (Eg≈0.95 eV)
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5. Methods of synthesis:
 By sol gel method
 By hydrothermal method
 By chemical vapor deposition
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6. Pyrite synthesis by hydrothermal method:
Iron and sulfur
sources; Na2S2O3,
either FeSO4.7H2O
or Fe(NO3)3.9H2O
Iron and sulfur
sources were
separately dissolved
in deionized water
and stirred with
magnetic stirrer
mixed and
transferred into a
stainless steel
autoclave with 2
litter capacity and
filled with distilled
water up to 40% of
the total volume
The autoclave was
sealed and
maintained at a
temperature in the
range of 130–180˚C
for a period of 2 to
h.
Cooled at room
temperature,
precipitates were
filtered and washed
with distil water.
Carbon disulfide use
to remove
and then dried at
80˚C for 4 h.
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7. Pyrite synthesis by sol gel dip coating
method:
FeS2 thin film was prepared using the sol–gel dip-coating method; in two
steps:
 preparation of Fe2O3 precursors
 sulfurization
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8. Step one:
preparation of Fe2O3 precursors
 Precursor Fe2O3 thin films were coated on quartz substrate via a sol–gel dip-coating method.
 Hydrate ferric nitrate Fe(NO3)3·9H2O was dissolved in a mixture of 2-methoxythanol and acetyl
acetone with a molar ratio 10:1. The solution was stirred at room temperature for 2 h to form the nitrate
sol.
 Quartz slide substrate cleaned with chromic acid lotion, immersed in ethanol in an ultrasonic bath for
15 min, rinsed with de-ionized water and then dried in air at 373 K.
 The gel films were coated on quartz substrates at 303 K using a dip coater.
 After dipping, the deposited gel film was dried at 373 K in air for 20 min. This dipping and drying
process was repeated for six cycles to obtain the expected thickness of each film sample.
 The finished gel films were annealed at 773 K for 30 min to form the precursor films.
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9. Step two:
sulfurization
 The precursor Fe2O3 films and a certain amount of sublimed sulfur powder were sealed in glass
ampoules. These sealed samples were annealed at 673 K and held for different periods with a
heating rate of 3 K/min.
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10. Pyrite synthesis by atmospheric pressure
chemical vapor deposition method:
 Di-tert butyl disulfide and FeCl3 were used as iron and sulfur precursors.
 Atmospheric pressure chemical vapor deposition (AP-CVD) is used to synthesize pyrite thin film.
The iron deposited on Mo coated glass is annealed at 400ºC for 2 hrs in oxygen.
 The annealed sample is taken and is placed inside the CVD chamber. The experiment is
performed for 2 hours in the temperature range of 375°C to 400°C with an inflow of a mixture of
Ar/H2 gas and vapor of Di-tert butyl disulfide.
 After 120 mins of operation, the gas is turned off and the furnace was cooled to 20ºC in 20 mins.
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11. Figure no.1:
Diagram of
chemical vapor
deposition
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12. references:
https://www.researchgate.net/publication/2515177
76_Pyrite_FeS_2_thin_films_deposited_by_solgel_m
ethodhttps://www.researchgate.net/publication/25
1517776_Pyrite_FeS_2_thin_films_deposited_by_sol
-gel_method
https://www.researchgate.net/publication/240386
042_Pyrite_FeS_2_films_prepared_via_sol-
gel_hydrothermal_method
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