In this slideshow three types of synthesis method is discussed .

1. Synthesis Of Nanomaterial
SOLVOTHERMAL METHOD
PHOTOCHEMICAL METHOD
ELECTROCHEMICAL METHOD

2. SOLVOTHERMAL METHOD

3. History:
Solvothermal synthesis route was first proposed by YI-TAI
QIAN in 1996 from university science and technology of china
This method is very similar to Hydrothermal route, the only
difference in the precursor solution is usually No aqueous but
this not always in the case in literature uses of the expression
SOLVO -- THERMAL
Solvant -- use of the temperature

4. SOLVOTHERMAL PROCESSES:
A “solvothermal reaction can be defined as a
chemical reaction (or a transformation) between
precursor(s) in a solvent (in a close system) at a
temperature higher than the boiling temperature of
this solvent and under high pressure”.
 auto geneous pressure or imposed pressure.
 Subcritical or supercritical domain.
 Homogeneous or heterogeneous system.

5. MAIN FACTORS GOVERNING THE SOLVOTHERMAL CRYSTAL GROWTH
CHEMICAL FACTORS
PHYSICAL FACTORS
KINETICAL FACTORS
- nature of the solvant,
- nature of the nutrient,
- nature of the seeds,
- the interactions solvant/ wall of the HP. Vessel
- the Crystal growth temperature (Tgrowth),
- the T value,
- the pressure value,
- the hydrodynamics in the crystal-growth system.
- the kinetics of dissolution,
- the kinetics characterizing the diffusion of chemical species,
- the crystal growth kinetics,
- the duration of the crystal growth.

6. 6
New Trends in Solvothermal Crystal Growth Processes
Recently one-dimensionnal (1D) nano-structures (wires, rods, tubes…) have been
the focus of intensive research owing to their applications in mesoscopic physics
and fabrication of nanoscale devices.
The formation of a 1D nanostructure depends on two steps:
- the nucleation,
- the crystal growth.
In addition for generating nanostructures three main parameters must be
controlled:
 the dimensions,
 the morphology,
 the monodispersity (or uniformity)

7. 7
THE SOLVOTHERMAL PROCESSES AND
THE CRYSTAL GROWTH AT THE NANOSCALE
Schematic illustrations of the different strategies for achieving 1D growth.
A)  Induction of 1D morphology through the
anisotropic structure,
B)  confinement by a liquid droplet in the
liquid/solid process,
C)  use of templates,
D)  use of capping agents able to modify the
growth rate in one direction,
E)  self assembly of OD nanostructure,
F)  size reduction of 1D microstructure.

8. Autoclave for cooking Autoclave for medical Autoclave for solovothermal
Apparatus in Solvothermal Synthesis

9. Apparatus in Solvothermal Synthesis – 2
whole apparatus part of chamber components of chamber

10.  Solovothermal are usually thick walled steel cylinders with hermetic seal which must
withstand high temperature and pressure for prolonged periods of times.

The autoclave material must be inert with respect to the solovent. The closure is the
most important element of the autoclave.

To prevent corroding of the internal cavity of the autoclave, prodective inserts are
genrally used. These may have the same shape of the autoclave and fit in the
internal cavity.

Inserts may be made up of carbon free iron, glass or quarts, copper or Teflon
depending on the temperature and material used.
Apparatus in Solvothermal Synthesis - 3

11. 1.most material can be made soluble in proper solvent by heating and most material can be made soluble
in proper solvent by heating and pressure in the system close to its critical point;
2.significant improvement in the chemical activity of the react and the possibility to replace the solid state
synthesis and materials which may not be obtained via solid state reaction may be prepared through
solvothermal synthesis.
3. Products of intermediate state metastable state and specific phase maybe easily produced, novel
components of metastable state and other specific contents state may be synthesized.
4. Easy and precise to control of the size shape distribution crystallinity of the final product through ajay
singh the parameters such a reaction temperature, reaction time, solvent type, surfactant type and
precursor time.
5. Substances which which are low in melting point high in vapour pressure and tend to go pyrolysis will be
obtained.
6. Mass production of samples solovothermal/hydrothermal.
Advantages:

12. Disadvantages:
1.The need to expensive autoclave.
2.safety issues during the reaction process.
3.impossibility observing the reaction process.

13. Applications
1.We can center size of various kind of Nano structures
through solvothermal approaches including medal oxides
carbonaceous Nano structures and etc..
2.We can also produce zeolite ,nano wires, carbon nanotubes

14. Examples

17. PHOTOCHEMICAL METHOD

18. Photochemical method
• Photochemistry is the branch of chemistry concerned with the chemical
effects of light. Generally, this term is used to describe a chemical reaction
caused by absorption.
• Photochemical reactions require a light source that
emits wavelengths.
Ultraviolet (wavelength from 100 to 400 nm)
Visible light (400 – 750 nm)
Infrared radiation (750 – 2500 nm)

19. Sources of Photochemical
In the early experiments sunlight was the light source.
Mercury vapor lamps
Low pressure mercury vapor lamps (254 nm)
Laser beams
LEDs have a relatively narrowband
Rayonet lamps
Poly chromatic sources
Monochromatic Source
The emitted light must of course reach the targeted functional group

20. • The solvent is an important experimental parameter.
• Chlorinated solvents are avoided because the C-Cl bond can lead to chlorination of the
substrate.
• Strongly absorbing solvents prevent photons from reaching the substrate.
• Hydrocarbon solvents absorb only at short wavelengths and these preferred for
Photochemical.
• Experiments requiring high energy photons.
• Solvents containing unsaturation absorb at longer wavelengths and can usefully filter out
short wavelengths.
Solvents:

23. ELECTROCHEMICAL METHOD

24.  It is possible to control particle size by adjusting the electrolysis
parameters and to improve homogeneity of Ag NPs by changing
the composition of the electrolytic solution.
 PVP can be used to protect Ag NPs from agglomeration,
significantly reduces silver deposition rate and promotes silver
nucleation & Ag NPs formation rate.
Electrochemical method

25. Electrochemical method for synthesis of Ag NPs

26.  The rate of reaction was found to increase with:
– Decrease in the distance between the electrodes (1–2 cm)
– Increase in the voltage (5–50 V DC)
– Increase in the temperature
 A longer reaction time resulted in:
– Larger size of Ag NPs
– Higher concentration of Ag NPs

27.  Alternatively, the cathode could be other metals such as
platinum.
 The presence of PVA (1–100 ppm):
– Acts as supporting electrolyte
– Accelerates the NP nucleation and growth
– Produces highly concentrated suspensions of NPs

28. Electrochemical method for synthesis of Ag NPs

29. THANK YOU
ARJUN KUMAR B
M.Sc. Nano science & technology
I year