**1. Introduction**

## **1.1 General introduction of pectin**

Pectin is a natural organic compound that has unique structure and characteristics. The uniqueness of the pectin structure is seen from its constituents consisting of three components [1–4], namely, homogalacturonan (HG), rhamnogalacturonan-I (RGI), and rhamnogalacturonan-II (RGII). In principle, the main structure is RG. Furthermore, the functional groups possessed by pectin are ferulic acid, methoxy, acetyl esters, and esters. Interactions between the functional groups that are held provide uniqueness to the characteristics of pectin through hydrogen bonds, hydrophobic interactions, polyelectrolyte behavior, specific ion interactions, and even covalent bonds [5, 6] as external cation binding matrices prepared in the preparation of the advanced material.

Schematically the binding and distribution of cations dissolved in the pectin solution can be illustrated as in **Figure 1**.

In general, pectin can bind various cations with oxidation numbers of +1, +2, and +3 through various functional groups that belong to one or more pectin molecules, so that the cations bound are ready to react to produce a compound that will be welldistributed and the size of the particles produced can reach the nanoscale.

### **1.2 General introduction of LaCrO3**

Perovskite compounds, ABO3 (where A = cation of alkali, alkaline earth, or lanthanide metal and B = cation of transition metal), have unique chemical and physical properties such as oxidative, magnetic, conductive, refractive, luminescent, and catalytic. With such interesting and valuable characteristics, these compounds have been utilized tremendously in electronic devices as a tuner of the dielectric/ferroelectric responses [7] and an overcomer inefficiency on photovoltaics and other optoelectronic devices [8], sensors as a hydrazine detector [9] and ozone sensing property [10], magnetisms as a huge magnetoresistance [11] and a magnetoelectric response [12], photoluminescences as a highly photoluminescent thin film [13] and a light-emitting material [14], catalysts as CO2/H2 converter into alcohol [15] and pollutant decomposer [16], solid oxide fuel cells as a self-anode in the next power generator [17] and a good performance cathode [18], and photocatalysts as a photo-oxidator of benzylic alcohol [19] and a decomposer of dyes [20].

Perovskite structural material (ABO3) can be synthesized by mixing the oxide of lanthanide or third main group elements with the oxide of the transition elements. The cations can fit into both the A and B sites of the perovskite structure. In principle, the ABO3 structure should obey the formulae of Goldschmidt's tolerance factor [21], t = 0.71(rA + rO)/(rB + rO). This t-value led to the formation of crystalline structures such as cubic [22], orthorhombic [23], and hexagonal forms [24].

One of the perovskite materials, lanthanum chromites (LaCrO3), has been extensively examined due to its applicability as interconnector for solid oxide fuel cell [25], excellent chemical stabilizer [26], good electrical properties at high temperature [27], total oxidation catalyst [28], partial oxidation catalyst [29], oxidative dehydrogenation catalyst [30], and photocatalyst [31]. Nowadays, various kinds of methods have been utilized to prepare the perovskite compounds such as hydrothermal [32, 33], precipitation [34, 35], coprecipitation [36, 37], auto-combustion [38, 39], and sol-gel [40–42]. Among these various kinds of the preparation methods, sol-gel holds particular importance, since it offers many advantages over the others. In the sol-gel technique, a homogeneous product is affected by all steps of preparation such as selection and dissolution of raw material, homogeneous mixing, and pH and temperature adjustments. In addition, these steps led to the opportunity to gain the nanomaterial. Therefore, unique

**109**

**Figure 2.**

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis…*

physical and chemical properties of nanomaterial will be more feasible to obtain compared to their micro- and macro-size counterparts in a huge range of updated

Since the transformation of raw materials from the dissolved state into a solid state is also crucial in the sol-gel method, gelation, as well as solidification, determines the particle size of the product. To gain the nanomaterial, the agglomeration should be avoided by controlling carefully the process of both gelation and solidifi-

In heterogeneous photocatalytic processes, the semiconductors used are chalcogenide-type semiconductor materials (oxides, TiO2, ZnO, ZrO, and CeO2, or sulfides, ZnS and CdS). Semiconductors can be used as photocatalyst because they have a void energy region called band-gap energy, which lies between the conduction band boundary (LUMO) and the valence band (HOMO) that does not provide energy for promoting recombination of electrons and holes produced by a photoac-

This semiconductor will function as a catalyst if it is illuminated with photons that have energy that is equal to or more than the energy bandgap (Eg) of the semiconductor used (hv ≥ Eg). Induction by these rays will excite the electrons (from the valence to the conduction band) in semiconductor materials [46]. As a result of

are separated into free photoelectrons in the conduction band and photo hole in the

)

) which

the photon illumination, the formation of electron pairs (e<sup>−</sup>) and holes (h+

There are several possibilities that occur in electron-hole pairs, namely:

2.Electron-hole pairs recombine on the surface (surface recombination) or in

valence band is ready to trigger the reaction as shown in **Figure 2**.

Semiconductor + hυ → (eCB−+ hVB<sup>+</sup>

1.Some pairs recombine in particles (volume recombination).

bulk particles in just a few nanoseconds (energy is lost as heat).

The reaction that occurs in this event is:

*Band-gap energy diagram in the photocatalytic process ([47]*

*DOI: http://dx.doi.org/10.5772/intechopen.83625*

cation as well as that of thermal treatment.

**1.3 Typical property of photocatalyst**

tivation in these semiconductors.

technologies [43–45].

**Figure 1.** *Illustration of binding of cations by pectin during the dissolution process.*

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis… DOI: http://dx.doi.org/10.5772/intechopen.83625*

physical and chemical properties of nanomaterial will be more feasible to obtain compared to their micro- and macro-size counterparts in a huge range of updated technologies [43–45].

Since the transformation of raw materials from the dissolved state into a solid state is also crucial in the sol-gel method, gelation, as well as solidification, determines the particle size of the product. To gain the nanomaterial, the agglomeration should be avoided by controlling carefully the process of both gelation and solidification as well as that of thermal treatment.

#### **1.3 Typical property of photocatalyst**

*Pectins - Extraction, Purification, Characterization and Applications*

solution can be illustrated as in **Figure 1**.

**1.2 General introduction of LaCrO3**

a decomposer of dyes [20].

Schematically the binding and distribution of cations dissolved in the pectin

Perovskite compounds, ABO3 (where A = cation of alkali, alkaline earth, or lanthanide metal and B = cation of transition metal), have unique chemical and physical properties such as oxidative, magnetic, conductive, refractive, luminescent, and catalytic. With such interesting and valuable characteristics, these compounds have been utilized tremendously in electronic devices as a tuner of the dielectric/ferroelectric responses [7] and an overcomer inefficiency on photovoltaics and other optoelectronic devices [8], sensors as a hydrazine detector [9] and ozone sensing property [10], magnetisms as a huge magnetoresistance [11] and a magnetoelectric response [12], photoluminescences as a highly photoluminescent thin film [13] and a light-emitting material [14], catalysts as CO2/H2 converter into alcohol [15] and pollutant decomposer [16], solid oxide fuel cells as a self-anode in the next power generator [17] and a good performance cathode [18], and photocatalysts as a photo-oxidator of benzylic alcohol [19] and

Perovskite structural material (ABO3) can be synthesized by mixing the oxide of lanthanide or third main group elements with the oxide of the transition elements. The cations can fit into both the A and B sites of the perovskite structure. In principle, the ABO3 structure should obey the formulae of Goldschmidt's tolerance factor [21], t = 0.71(rA + rO)/(rB + rO). This t-value led to the formation of crystalline structures such as cubic [22], orthorhombic [23], and hexagonal forms [24]. One of the perovskite materials, lanthanum chromites (LaCrO3), has been extensively examined due to its applicability as interconnector for solid oxide fuel cell [25], excellent chemical stabilizer [26], good electrical properties at high temperature [27], total oxidation catalyst [28], partial oxidation catalyst [29], oxidative dehydrogenation catalyst [30], and photocatalyst [31]. Nowadays, various kinds of methods have been utilized to prepare the perovskite compounds such as hydrothermal [32, 33], precipitation [34, 35], coprecipitation [36, 37], auto-combustion [38, 39], and sol-gel [40–42]. Among these various kinds of the preparation methods, sol-gel holds particular importance, since it offers many advantages over the others. In the sol-gel technique, a homogeneous product is affected by all steps of preparation such as selection and dissolution of raw material, homogeneous mixing, and pH and temperature adjustments. In addition, these steps led to the opportunity to gain the nanomaterial. Therefore, unique

distributed and the size of the particles produced can reach the nanoscale.

In general, pectin can bind various cations with oxidation numbers of +1, +2, and +3 through various functional groups that belong to one or more pectin molecules, so that the cations bound are ready to react to produce a compound that will be well-

**108**

**Figure 1.**

*Illustration of binding of cations by pectin during the dissolution process.*

In heterogeneous photocatalytic processes, the semiconductors used are chalcogenide-type semiconductor materials (oxides, TiO2, ZnO, ZrO, and CeO2, or sulfides, ZnS and CdS). Semiconductors can be used as photocatalyst because they have a void energy region called band-gap energy, which lies between the conduction band boundary (LUMO) and the valence band (HOMO) that does not provide energy for promoting recombination of electrons and holes produced by a photoactivation in these semiconductors.

This semiconductor will function as a catalyst if it is illuminated with photons that have energy that is equal to or more than the energy bandgap (Eg) of the semiconductor used (hv ≥ Eg). Induction by these rays will excite the electrons (from the valence to the conduction band) in semiconductor materials [46]. As a result of the photon illumination, the formation of electron pairs (e<sup>−</sup>) and holes (h+ ) which are separated into free photoelectrons in the conduction band and photo hole in the valence band is ready to trigger the reaction as shown in **Figure 2**.

The reaction that occurs in this event is:

 Semiconductor + hυ → (eCB−+ hVB<sup>+</sup> )

There are several possibilities that occur in electron-hole pairs, namely:


**Figure 2.** *Band-gap energy diagram in the photocatalytic process ([47]*

The electron-hole pair recombination reaction can be written as follows:

 Semiconductor (e − CB + h<sup>+</sup> VB) → semiconductor + heat

3.Each electron pair can react with donor species (D) and acceptor (A), which are adsorbed on the particle surface. In other words, the electrons in the conduction band that reach the surface will reduce the substrate (A) or solvent on the surface of the particles, while the holes in the valence band will oxidize the substrate (D) either directly or indirectly through hydroxyl radical formation. This phenomenon follows the reaction equation as follows:

 hυ + semiconductor → e <sup>−</sup> + h<sup>+</sup> A(ads) + e <sup>−</sup> → A<sup>−</sup> (ads) D(ads) + h<sup>+</sup> → D<sup>+</sup> (ads)

Some possible reactions that can occur with radical ions formed (A<sup>−</sup> and D+ ) include:


In general, the process of the occurrence of a photocatalytic reaction based on the energy-gap concept indicates the difference in HOMO energy (the top band of valence contains electrons) and LUMO (the lowest band of conduction without electrons) that must be passed. In other words, the promotion of electrons from the top band of valence to the lowest band of conduction requires minimum energy equivalent to its band-gap energies. If the energy owned is zero or larger than 4 eV, owned are zero or large (>4 eV), then each is a metal or insulator, whereas semiconductor has energy between these values. Furthermore, the band-gap energy is classified as direct and indirect. Direct means that the minimum energy from the lowest band of conduction is just above the maximum energy of the valence band at the same momentum of crystals. If the condition is not so, it is called indirect bandgap energy. The range of band-gap energy possessed by a material will determine the type of energy that will be used so that a photocatalytic reaction can occur. The type of energy can be used for the reaction as shown in **Figure 3**.

In principle, all light electromagnetic waves can be used as an energy source for a chemical reaction process. So far, light that can be used as a trigger for chemical reactions through electron transfer from the HOMO to the LUMO level in the degradation and/or breaking of a compound bond into an environmentally friendly product is visible and ultraviolet.

Visible radiation is often used to degrade toxic compounds of dyes since the waste of dyes which is channeled directly into a river or sea body will have a negative effect

**111**

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis…*

**Num Type of bond Bond energy**

 **H▬H** 436 11.58 **C▬H** 413 10.97 **O▬H** 366 9.72 **C▬O** 360 9.56 **C▬C** 348 9.25 **C**〓**C** 614 16.31 **C**〓**O** 745 19.79 **C**〓**N** 615 16.33 **C**☰**C** 839 22.29 **N**☰**N** 941 24.99

**(kJ/mol) (eV)**

on aquatic biota. In general, visible light radiation has a wavelength range of 400— 800 nm. In other words, the energy needed to break the chemical bonds of a compound is low. Generally, these dyes are compounds that have chromophore groups, such as methine, nitro, azo, anthraquinone, triarylmethane, and phthalocyanine groups. In fact, dyes used in industry can be either natural compounds or syntheses. Ultraviolet radiation has a high ability to breakdown the bond and cause decomposition because of its high energy compared to infrared radiation and visible light [48]. Sources of ultraviolet radiation can be obtained from sunlight or artificial light. Ultraviolet (UV) radiation of the sun is electromagnetic energy with wavelengths between 200 and 400 nm and has more energy than visible light. Based on

1.UVA with a wavelength of 320—400 nm is a high wavelength and emits

2.UVB with a wavelength of 280–320 nm is a shorter wavelength and is more intense than UVA. UVB is more strongly absorbed by several biomolecular

3.UVC with a wavelength of 200—280 nm is the most intensive and dangerous

UV radiation and has the potential to cause damage to organisms.

radiation of constant magnitude throughout the year. This radiation can cause

its wavelength, solar UV radiation is divided into:

premature aging of the skin.

pollutants.

*DOI: http://dx.doi.org/10.5772/intechopen.83625*

*Schematic radiation energy of electromagnetic wavelength.*

**Figure 3.**

**Table 1.**

*Some typical bonds and bond energies.*

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis… DOI: http://dx.doi.org/10.5772/intechopen.83625*

#### **Figure 3.**

*Pectins - Extraction, Purification, Characterization and Applications*

Semiconductor (e

The electron-hole pair recombination reaction can be written as follows:

3.Each electron pair can react with donor species (D) and acceptor (A), which are adsorbed on the particle surface. In other words, the electrons in the conduction band that reach the surface will reduce the substrate (A) or solvent on the surface of the particles, while the holes in the valence band will oxidize the substrate (D) either directly or indirectly through hydroxyl radical formation.

<sup>−</sup> → A<sup>−</sup>

Some possible reactions that can occur with radical ions formed (A<sup>−</sup> and D+

In general, the process of the occurrence of a photocatalytic reaction based on the energy-gap concept indicates the difference in HOMO energy (the top band of valence contains electrons) and LUMO (the lowest band of conduction without electrons) that must be passed. In other words, the promotion of electrons from the top band of valence to the lowest band of conduction requires minimum energy equivalent to its band-gap energies. If the energy owned is zero or larger than 4 eV, owned are zero or large (>4 eV), then each is a metal or insulator, whereas semiconductor has energy between these values. Furthermore, the band-gap energy is classified as direct and indirect. Direct means that the minimum energy from the lowest band of conduction is just above the maximum energy of the valence band at the same momentum of crystals. If the condition is not so, it is called indirect bandgap energy. The range of band-gap energy possessed by a material will determine the type of energy that will be used so that a photocatalytic reaction can occur. The type

In principle, all light electromagnetic waves can be used as an energy source for a chemical reaction process. So far, light that can be used as a trigger for chemical reactions through electron transfer from the HOMO to the LUMO level in the degradation and/or breaking of a compound bond into an environmentally friendly

Visible radiation is often used to degrade toxic compounds of dyes since the waste of dyes which is channeled directly into a river or sea body will have a negative effect

(ads)

(ads)

react between fellow radical ions or react with adsorbates (species

combine by transferring the electron back to form an excited state

diffuse from the surface of the semiconductor and participate in

VB) → semiconductor + heat

<sup>−</sup> + h<sup>+</sup>

)

− CB + h<sup>+</sup>

This phenomenon follows the reaction equation as follows:

hυ + semiconductor → e

D(ads) + h<sup>+</sup> → D<sup>+</sup>

from one of the reactants or releasing heat.

chemical reactions that occur in the solution medium.

of energy can be used for the reaction as shown in **Figure 3**.

A(ads) + e

**110**

include:

a.A<sup>−</sup> and D<sup>+</sup>

b.A<sup>−</sup> and D<sup>+</sup>

c.A<sup>−</sup> and D<sup>+</sup>

adsorbed to the surface).

product is visible and ultraviolet.

*Schematic radiation energy of electromagnetic wavelength.*


#### **Table 1.**

*Some typical bonds and bond energies.*

on aquatic biota. In general, visible light radiation has a wavelength range of 400— 800 nm. In other words, the energy needed to break the chemical bonds of a compound is low. Generally, these dyes are compounds that have chromophore groups, such as methine, nitro, azo, anthraquinone, triarylmethane, and phthalocyanine groups. In fact, dyes used in industry can be either natural compounds or syntheses.

Ultraviolet radiation has a high ability to breakdown the bond and cause decomposition because of its high energy compared to infrared radiation and visible light [48]. Sources of ultraviolet radiation can be obtained from sunlight or artificial light. Ultraviolet (UV) radiation of the sun is electromagnetic energy with wavelengths between 200 and 400 nm and has more energy than visible light. Based on its wavelength, solar UV radiation is divided into:


Therefore, to choose a type of UV light in photocatalytic reaction depends on the type of bond and the energy required. In general, the type of bond with its energy can be seen in **Table 1**.

#### **2. Method of preparation**

Preparation of LaCrO3 catalyst material was carried out using the sol-gel method with pectin as an emulsifying agent. The preparation was conducted by dissolving specified mass of La(NO3)3.9H2O and Cr(NO3)3.6H2O, respectively, in 100 mL of pectin solution (4 g pectin). The overall procedure was described in the previous article [49].

## **3. Characterizations**

Before the material made was applied, the photocatalyst was characterized to determine the physical and chemical properties associated through X-ray diffraction analysis, electron transmission microscopy, distribution of particle distribution, energy-gap, and functional groups related to the structural formation and the acidity of Brønsted-Lowry and Lewis.

#### **3.1 Analysis of X-ray diffraction**

X-ray diffraction can be utilized to identify the phase formed and the relative percentages of different phases of the materials obtained. Then, the real structural parameters like particle size, lattice parameters (a, b, and c), lattice volume, and theoretical density can be calculated from their diffractogram using Rietveld calculation [50].

X-ray diffraction experiments are carried out by the procedure as described in the previous article [49]. To know the crystallite size, the representative peak of a diffractogram can be elucidated by using the Scherrer method of calculation [51]. The results of the diffractogram, determination of the size of the crystalline phase, and the Rietveld calculation are presented in **Figure 4**.

In general, the results of LaCrO3 prepared using pectin provide a single crystalline phase, nanosize, and other parameter values shown in **Table 2**.

#### **3.2 Transmission electron microscope analysis**

TEM can be used to study the morphology and surface characteristics of the perovskite nanomaterials. To evaluate the surface morphology, the samples were

#### **Figure 4.**

*Diffractogram of LaCrO3 (a) experimental results and (b) the result of the Rietveld calculation using LaCrO3 calcined at 700°C.*

**113**

tion) happened.

presented in **Figure 5**.

**Table 2.**

**Figure 5.**

*(c) 800°C.*

30, and 28 nm, respectively.

**3.3 Particle size distribution analysis**

600, 700, and 800°C, respectively [49].

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis…*

**Num Parameter LaCrO3 calcined at Ref**

1 Crystalline phase Cubic Orthorhombic Orthorhombic [50] 2 Crystalline size (nm) 24.84 24.12 27.09 [48] 3 hkl plane 110 112 121 [50]

**600°C 700°C 800°C**

characterized using TEM. The analysis was conducted on polished and thermally etched samples with different magnifications. TEM results of LaCrO3 material are

*TEM micrographs of LaCrO3 prepared using pectin as the emulsifying agent: calcined at (a) 600, (b) 700, and* 

It seems that there is still a relatively large region of agglomeration in the crystalline phase formed in each of these preparations. Nevertheless, the particle sizes obtained using TEM in this study are significantly smaller than that of LaCrO3 prepared using sol-gel method reported by another research group [52]. It was found that the particle sizes of the sample calcined at 600, 700, and 800°C are 34.6,

Analysis of the particle size distribution of the solid sample was examined by the technique of dynamic light scattering (DLS). The measurement of the sample using this instrument can be determined by either wet or dry method. If a measurement is using the wet method, the sample is prepared using alcohol dispersant such as methanol, ethanol, or propanol. However, if the measurement is using a dry method on preparing the sample, air dispersant could be utilized. More information can be obtained in the manual book [53]. The more important in preparing sample is to prevent the irreversible change to the particle (dissolution, milling, or aggrega-

From **Figure 6**, it can be implied that there are two or three regions of the particle size which are quantum dot, nano-, and micron sizes. Overall, it can be said that nanosize of the particles 21.9, 86.4, and 89.11% referred to LaCrO3 calcined at

The results also can be implied that the more nanosize particle obtained, the higher the temperature of calcination applied. In other words, the temperature of calcination plays a role to determine the nanosize of the particle. In other studies,

*DOI: http://dx.doi.org/10.5772/intechopen.83625*

*Parameters of LaCrO3 prepared in various calcination temperatures.*

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis… DOI: http://dx.doi.org/10.5772/intechopen.83625*


#### **Table 2.**

*Pectins - Extraction, Purification, Characterization and Applications*

can be seen in **Table 1**.

**3. Characterizations**

acidity of Brønsted-Lowry and Lewis.

and the Rietveld calculation are presented in **Figure 4**.

**3.2 Transmission electron microscope analysis**

line phase, nanosize, and other parameter values shown in **Table 2**.

**3.1 Analysis of X-ray diffraction**

**2. Method of preparation**

Therefore, to choose a type of UV light in photocatalytic reaction depends on the type of bond and the energy required. In general, the type of bond with its energy

Preparation of LaCrO3 catalyst material was carried out using the sol-gel method with pectin as an emulsifying agent. The preparation was conducted by dissolving specified mass of La(NO3)3.9H2O and Cr(NO3)3.6H2O, respectively, in 100 mL of pectin solution (4 g pectin). The overall procedure was described in the previous article [49].

Before the material made was applied, the photocatalyst was characterized to determine the physical and chemical properties associated through X-ray diffraction analysis, electron transmission microscopy, distribution of particle distribution, energy-gap, and functional groups related to the structural formation and the

X-ray diffraction can be utilized to identify the phase formed and the relative percentages of different phases of the materials obtained. Then, the real structural parameters like particle size, lattice parameters (a, b, and c), lattice volume, and theoretical density can be calculated from their diffractogram using Rietveld calculation [50]. X-ray diffraction experiments are carried out by the procedure as described in the previous article [49]. To know the crystallite size, the representative peak of a diffractogram can be elucidated by using the Scherrer method of calculation [51]. The results of the diffractogram, determination of the size of the crystalline phase,

In general, the results of LaCrO3 prepared using pectin provide a single crystal-

TEM can be used to study the morphology and surface characteristics of the perovskite nanomaterials. To evaluate the surface morphology, the samples were

*Diffractogram of LaCrO3 (a) experimental results and (b) the result of the Rietveld calculation using LaCrO3*

**112**

**Figure 4.**

*calcined at 700°C.*

*Parameters of LaCrO3 prepared in various calcination temperatures.*

**Figure 5.** *TEM micrographs of LaCrO3 prepared using pectin as the emulsifying agent: calcined at (a) 600, (b) 700, and (c) 800°C.*

characterized using TEM. The analysis was conducted on polished and thermally etched samples with different magnifications. TEM results of LaCrO3 material are presented in **Figure 5**.

It seems that there is still a relatively large region of agglomeration in the crystalline phase formed in each of these preparations. Nevertheless, the particle sizes obtained using TEM in this study are significantly smaller than that of LaCrO3 prepared using sol-gel method reported by another research group [52]. It was found that the particle sizes of the sample calcined at 600, 700, and 800°C are 34.6, 30, and 28 nm, respectively.

#### **3.3 Particle size distribution analysis**

Analysis of the particle size distribution of the solid sample was examined by the technique of dynamic light scattering (DLS). The measurement of the sample using this instrument can be determined by either wet or dry method. If a measurement is using the wet method, the sample is prepared using alcohol dispersant such as methanol, ethanol, or propanol. However, if the measurement is using a dry method on preparing the sample, air dispersant could be utilized. More information can be obtained in the manual book [53]. The more important in preparing sample is to prevent the irreversible change to the particle (dissolution, milling, or aggregation) happened.

From **Figure 6**, it can be implied that there are two or three regions of the particle size which are quantum dot, nano-, and micron sizes. Overall, it can be said that nanosize of the particles 21.9, 86.4, and 89.11% referred to LaCrO3 calcined at 600, 700, and 800°C, respectively [49].

The results also can be implied that the more nanosize particle obtained, the higher the temperature of calcination applied. In other words, the temperature of calcination plays a role to determine the nanosize of the particle. In other studies,

**Figure 6.** *The particle size distribution of the LaCrO3 calcined at (a) 600, (b) 700, and (c) 800°C.*

the particle size of LaCrO3 prepared using hydrothermal method was determined by PSA method. The result proved that the average size of particle is in the range of micron [54] and 57 nm [55].

#### **3.4 Analysis of diffuse reflectance UV-Vis spectroscopy**

In order to know the band-gap energy of the LaCrO3 prepared in a different calcined temperature, the analysis was run using diffuse reflectance UV-Vis spectroscopy as shown in **Figure 7**.

To determine the bandgap of a powder sample using the diffuse reflectance spectrophotometer is a common technique [56]. So, in this study the band-gap energy is calculated using a Kubelka-Munk method [57] based on the equation below:

$$\alpha \text{(h}\nu\text{)} \simeq \beta \text{ (h}\nu - \text{E}\_{\text{op}}\text{)}^{\text{n}}$$

where β is a constant and n is an index related to the possible type of electron transition. The value of n could be 1/2, 2, 3/2, and 3. Those values are corresponding

**115**

**Figure 8.**

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis…*

to the nature of electron transition. In principle, there are two kinds of electron transition, which are direct and indirect. If the n value is 1/2 or 2, it means allowed direct or indirect electron transition happened. But if the n value is 3/2 or 3, it

*Reflectance (A) and absorption (B) features of LaCrO3 calcined at 600, 700, and 800°C, respectively.*

The results of the band-gap energy from LaCrO3 calcined at 600, 700, and 800°C, respectively, are 2.62, 2.89, and 2.98 eV. The magnitude of those band-gap energies is

In principle, FTIR analysis in the material field is used to assess the functional

From **Figure 8**, it can be implied that perovskite LaCrO3 is actually formed and can be assessed based on the type of bond vibration which can be referred to in detail in the following literature [a]. The La▬O▬La and La▬O▬Cr bonds through

groups and what bonds are formed in the material prepared in relation to the expected compound. In preparing samples for their analysis, the procedures performed are standard and can be referenced in various libraries [49, 59, 60]. The chemical bonding and chemical structure of the prepared perovskites can be identified. The FTIR spectra can give structural confirmation supporting XRD

analysis. Infrared spectra of LaCrO3 material are presented in **Figure 8**.

*Infrared spectra of LaCrO3 calcined at (a) 600°C, (b) 700°C, and (c) 800°C [48].*

means forbidden direct or indirect electron transition occurred [58].

suitable for photocatalytic reactions using UV and visible light irradiation.

*DOI: http://dx.doi.org/10.5772/intechopen.83625*

**3.5 Fourier transform infrared analysis**

**Figure 7.**

*Pectins as Emulsifying Agent on the Preparation, Characterization, and Photocatalysis… DOI: http://dx.doi.org/10.5772/intechopen.83625*

**Figure 7.** *Reflectance (A) and absorption (B) features of LaCrO3 calcined at 600, 700, and 800°C, respectively.*

to the nature of electron transition. In principle, there are two kinds of electron transition, which are direct and indirect. If the n value is 1/2 or 2, it means allowed direct or indirect electron transition happened. But if the n value is 3/2 or 3, it means forbidden direct or indirect electron transition occurred [58].

The results of the band-gap energy from LaCrO3 calcined at 600, 700, and 800°C, respectively, are 2.62, 2.89, and 2.98 eV. The magnitude of those band-gap energies is suitable for photocatalytic reactions using UV and visible light irradiation.

#### **3.5 Fourier transform infrared analysis**

In principle, FTIR analysis in the material field is used to assess the functional groups and what bonds are formed in the material prepared in relation to the expected compound. In preparing samples for their analysis, the procedures performed are standard and can be referenced in various libraries [49, 59, 60].

The chemical bonding and chemical structure of the prepared perovskites can be identified. The FTIR spectra can give structural confirmation supporting XRD analysis. Infrared spectra of LaCrO3 material are presented in **Figure 8**.

From **Figure 8**, it can be implied that perovskite LaCrO3 is actually formed and can be assessed based on the type of bond vibration which can be referred to in detail in the following literature [a]. The La▬O▬La and La▬O▬Cr bonds through

**Figure 8.** *Infrared spectra of LaCrO3 calcined at (a) 600°C, (b) 700°C, and (c) 800°C [48].*

*Pectins - Extraction, Purification, Characterization and Applications*

the particle size of LaCrO3 prepared using hydrothermal method was determined by PSA method. The result proved that the average size of particle is in the range of

In order to know the band-gap energy of the LaCrO3 prepared in a different calcined temperature, the analysis was run using diffuse reflectance UV-Vis spec-

calculated using a Kubelka-Munk method [57] based on the equation below:

To determine the bandgap of a powder sample using the diffuse reflectance spectrophotometer is a common technique [56]. So, in this study the band-gap energy is

where β is a constant and n is an index related to the possible type of electron transition. The value of n could be 1/2, 2, 3/2, and 3. Those values are corresponding

**3.4 Analysis of diffuse reflectance UV-Vis spectroscopy**

*The particle size distribution of the LaCrO3 calcined at (a) 600, (b) 700, and (c) 800°C.*

α(hν) ≈ β (hν − Eop)<sup>n</sup>

**114**

micron [54] and 57 nm [55].

**Figure 6.**

troscopy as shown in **Figure 7**.

information on bending vibrations are increasingly apparent as the calcination temperature increases. In other words, the structure of LaCrO3 which is formed along with the increase in the calcination temperature is getting closer and can be assessed through the diffractogram data.

The results also reflect that the existence of Brønsted-Lowry and Lewis acid sites is indicated by the presence of absorption bands at wave number 1400 and 1630 cm<sup>−</sup><sup>1</sup> , respectively. In detail, the acidity characteristics of the LaCrO3 calcined at the various temperatures were described in the previous article [49].
