5. Conclusions

where A0 is the open loop gain, X1, X2, Y1, Y2, Z1 and Z2 represent the inputs of the analog

ð Þ X1 � X2 ð Þ¼ Y1 � Y2 SF Zð Þ 1 � Z2 (20)

SF <sup>þ</sup> <sup>Z</sup><sup>2</sup> (21)

(22)

multiplier, SF a scale factor, typically SF = 10 V and W = OUT, according to Figure 26.

<sup>W</sup> <sup>¼</sup> ð Þ <sup>X</sup><sup>1</sup> � <sup>X</sup><sup>2</sup> ð Þ <sup>Y</sup><sup>1</sup> � <sup>Y</sup><sup>2</sup>

Since Z2 = U2, Y1-Y2 = βU2, 0 ≤ β < 1, X2 = 0 and X1 = Z1 = W=U3, according to Figure 26.

<sup>U</sup><sup>3</sup> <sup>¼</sup> <sup>W</sup> <sup>¼</sup> <sup>U</sup><sup>2</sup>

The relation (6) together with the relation (2) represents the calculation method regarding the linearization of the signal generated by the Wheatstone bridge, via an operational in-amp

By considering the three previously analyzed electronic blocks, the electronic block for signal conditioning generated by the sensing element is obtained. Figure 27 shows the schematic of

Figure 27. Schematic of the electronic block for signal conditioning generated by the sensing element, single supply

4.6.3. Resulting structures for the electronic block for signal conditioning generated

<sup>1</sup> � <sup>β</sup>U<sup>2</sup> SF

Since A0 ! 72 dB can be considered as W/A0 ! 0 and the relation (19) becomes:

Since Z1 = W it is obtained:

86 Cerium Oxide - Applications and Attributes

instrumentation amplifier.

by the sensing element

bridge applications.

Finally,

is obtained

Cerium, by its unique electronic configuration ([Xe] 4f2 6s<sup>2</sup> ) and by the two common valence states Ce3+ and Ce4+ allowing a redox reaction between them which gives CeO2 excellent chemical and physical properties, is used in many applications, like as: three-way catalytic reactions to eliminate toxic automobile exhaust, the low-temperature water gas shift reaction, oxygen permeation membrane systems for fuel cells as well as gas sensors. For gas sensing applications, several sensitive elements based on CeO2 were tested to determine both this detection function as well as this performances:


radius of the doping ion. Therefore, the introduction of trivalent ions in ceria leads to the production of anion vacancies which may enhance catalytic and gas sensing.

References

DOI: 10.1038/am.2015.27

of Pure & Applied Physics. 2015;53:596-603

DOI: 10.1016/S0920-5861(01)00477-1

10.1007/s10854-018-9125-x

14392013005000021

2001;36:1105-1117. DOI: 10.1023/A:1004817506146

Advances. 2014;4:16782-16791. DOI: 10.1039/c4ra00861h

Research. 2016;19(2):478-482. DOI: 10.1590/1980-5373-MR-2015-0698

[1] Song S, Wang X, Zhang H. CeO2-encapsulated noble metal nanocatalysts: Enhanced activity and stability for catalytic application-review. NPG Asia Materials. 2015;7:e179.

Prototyping a Gas Sensors Using CeO2 as a Matrix or Dopant in Oxide Semiconductor Systems

http://dx.doi.org/10.5772/intechopen.80801

89

[2] Babitha KK, Sreedevi A, Priyanka KP, Sabu B, Vargheze T. Structural characterization and optic studies of CeO2 nanoparticles synthesized by chemical precipitation. Indian Journal

[3] Melchionna M, Fornasiero P. The role of ceria-based nanostructured materials in energy applications. Materials Today. 2014;17(7):349-357. DOI: 10.1016/j.mattod.2014.05.005

[4] Hadi A, Yaacob II. Synthesis of PdO/CeO2 mixed oxides catalyst for automotive exhaust emissions control. Catalysis Today. 2004;96(3):165-170. DOI: 10.1016/j.cattod.2004.06.118

[5] Andreeva D, Idakiev V, Tabakova T, Ilieva L, Falaras P, Bourlinos A, et al. Low-temperature water-gas shift reaction over Au/CeO2 catalysts. Catalysis Today. 2002;72(1-2):51-57.

[6] Kharton V, Figueiredo FM, Navarro L, Naumovich EN, Kovalevsky AV, Yaremchenko AA, et al. Ceria-based materials for solid oxide fuel cells. Journal of Materials Science.

[7] Ansari SA, Khan MM, Ansari MO, Lee SKJ, Cho MH. Band gap engineering of CeO2 nanostructure using an electrochemically active biofilm for visible light applications. RSC

[8] Prabaharana DMDM, Sadaiyandib K, Mahendran M, Sagadevand S. Structural, optical, morphological and dielectric properties of cerium oxide nanoparticles. Materials

[9] Shi H, Hussain T, Ahuja R, Kang TW, Luo W. Role of vacancies, light elements and rareearth metals doping in CeO2. Scientific Reports. 2016;6:31345. DOI: 10.1038/srep31345 [10] Alla SK, Kollu P, Singh Meena S, Poswal HK, Prajapat CL, Mandal RK, et al. Investigation of magnetic properties for Hf4+ substituted CeO2 nanoparticles for spintronic applications. Journal of Materials Science: Materials in Electronics. 2018;29(12):10614-10623. DOI:

[11] Kumar E, Selvarajan P, Muthura D. Synthesis and characterization of CeO2 nanocrystals by solvothermal route. Materials Research. 2013;16(2):269-276. DOI: 10.1590/S1516-

[12] Sun C, Li H, Zhang H, Wang Z, Chen L. Controlled synthesis of CeO <sup>2</sup> nanorods by a solvothermal method. Nanotechnology. 2005;16:1454-1463. DOI: 0957-4484/05/091454

[13] Laberty-Robert C, Long JW, Lucas EM, Pettigrew KA, Stroud RM, Doescher MS, et al. Solgel-derived ceria nanoarchitectures: Synthesis, characterization, and electrical prop-

erties. Chemistry of Materials. 2006;18(1):50-58. DOI: 10.1021/cm051385t


Based on these results, it can be stated that CeO2 is a good candidate in gas sensors applications.
