426
of hydrated ferric nitrate, NH 4 H 2 PO 4 , hydrated sodium sulfate, and glucose are
separately dissolved in distilled water and then mixed with each other for a few
minutes. The resultant mixture is transferred into a steel autoclave. The reaction is
performed at 180 °C for 48 h. Afterward, the obtained black product is left to cool
to room temperature and then rinsed with a distilled water/ethanol mixture. The
washed and dried product is finally calcined at 450 °C (Ji et al. 2018). The hydrothermal method is also very popular for the synthesis of inorganic–organic hybrid
materials such as Co(C 4 H 4 N 2 )(VO 3 ) 2 and Co(C 12 H 12 N 2 )(VO 3 ) 2 (Li and Bai 2008),
manganese tetraphosphonate (Stock et al. 2004), and metal diphosphonates (Stock
and Bein 2002).
Coprecipitation Method
Coprecipitation is a wet chemical synthesis method, including the occurrence of
nucleation, growth, and Ostwald ripening stages. The products are prepared from
the solution phase under supersaturation conditions. Nucleation forms a huge number of small initial nuclei. The formed nuclei can grow through Ostwald ripening
process. Such a process can result in the formation of aggregates, which consequently affect morphology and particle size (Athar 2015). As an example, to prepare
iron–titanium mixed oxide, FeSO 4 ·7H 2 O and Ti(SO 4 ) 2 ·4H2O are dissolved in water
to prepare a mixed salt solution. Then 12.5% ammonia solution is added to the solution until the pH value of ~7.0. The resultant gel is aged for 48 h to obtain a suitable
crystalline structure. After washing and drying, the gel is calcined in a furnace
(Chen et al. 2012).
Coprecipitation technique can be applied to synthesize core–shell strictures. For
this purpose, two or more water-soluble salts are first dissolved in water. Then, the
pH value of the mixture is adjusted by adding a suitable precipitating agent.
Figure 16.12 illustrates a schema of the formation of core–shell structure. The core
phase is first dispersed in an aqueous salt medium as colloidal form. Achieving a
desirable dispersion is very important in this stage. Then, the particles of shell are
precipitated on the outer surface of core particles by the addition of a precipitant or
acid/base with a proper concentration (Dembski et al. 2018).
Chemical Vapor Deposition
Chemical vapor deposition is an extensively used synthesis technique, during which
a thin film is formed on the surface of a substrate. The film is deposited through a
gas-phase chemical reaction. The chemical vapor deposition can be carried out in
different media in cold-wall/hot-wall reactors. The pressure of the reactor may be
controlled at sub-torr to above atmospheric pressure. The temperature is usually
over the range of 200–1600 °C (Yan and Xu 2010; Warwick et al. 2011). Typically,
chemical vapor deposition encompasses the chemical reaction of a metal-containing
species on a substrate. An illustration of the typical main steps is shown in Fig. 16.13.
R. M. Moattari and T. Mohammadi
of hydrated ferric nitrate, NH 4 H 2 PO 4 , hydrated sodium sulfate, and glucose are
separately dissolved in distilled water and then mixed with each other for a few
minutes. The resultant mixture is transferred into a steel autoclave. The reaction is
performed at 180 °C for 48 h. Afterward, the obtained black product is left to cool
to room temperature and then rinsed with a distilled water/ethanol mixture. The
washed and dried product is finally calcined at 450 °C (Ji et al. 2018). The hydrothermal method is also very popular for the synthesis of inorganic–organic hybrid
materials such as Co(C 4 H 4 N 2 )(VO 3 ) 2 and Co(C 12 H 12 N 2 )(VO 3 ) 2 (Li and Bai 2008),
manganese tetraphosphonate (Stock et al. 2004), and metal diphosphonates (Stock
and Bein 2002).
Coprecipitation Method
Coprecipitation is a wet chemical synthesis method, including the occurrence of
nucleation, growth, and Ostwald ripening stages. The products are prepared from
the solution phase under supersaturation conditions. Nucleation forms a huge number of small initial nuclei. The formed nuclei can grow through Ostwald ripening
process. Such a process can result in the formation of aggregates, which consequently affect morphology and particle size (Athar 2015). As an example, to prepare
iron–titanium mixed oxide, FeSO 4 ·7H 2 O and Ti(SO 4 ) 2 ·4H2O are dissolved in water
to prepare a mixed salt solution. Then 12.5% ammonia solution is added to the solution until the pH value of ~7.0. The resultant gel is aged for 48 h to obtain a suitable
crystalline structure. After washing and drying, the gel is calcined in a furnace
(Chen et al. 2012).
Coprecipitation technique can be applied to synthesize core–shell strictures. For
this purpose, two or more water-soluble salts are first dissolved in water. Then, the
pH value of the mixture is adjusted by adding a suitable precipitating agent.
Figure 16.12 illustrates a schema of the formation of core–shell structure. The core
phase is first dispersed in an aqueous salt medium as colloidal form. Achieving a
desirable dispersion is very important in this stage. Then, the particles of shell are
precipitated on the outer surface of core particles by the addition of a precipitant or
acid/base with a proper concentration (Dembski et al. 2018).
Chemical Vapor Deposition
Chemical vapor deposition is an extensively used synthesis technique, during which
a thin film is formed on the surface of a substrate. The film is deposited through a
gas-phase chemical reaction. The chemical vapor deposition can be carried out in
different media in cold-wall/hot-wall reactors. The pressure of the reactor may be
controlled at sub-torr to above atmospheric pressure. The temperature is usually
over the range of 200–1600 °C (Yan and Xu 2010; Warwick et al. 2011). Typically,
chemical vapor deposition encompasses the chemical reaction of a metal-containing
species on a substrate. An illustration of the typical main steps is shown in Fig. 16.13.
R. M. Moattari and T. Mohammadi