**Author details**

This is a very exciting result since it opens a wide range of possibilities for using

The current chapter highlights that the transport properties of BaCe0.9Y0.1O3-<sup>δ</sup>

(BCY10) in very low humidity conditions are dependent on the nature of the surrounding atmosphere and on the temperature, being significantly different in reducing and oxidising conditions and at high and low temperatures. In reducing conditions, BCY10 shows a very high protonic conductivity (*e.g.* � <sup>10</sup>�<sup>3</sup> S cm�<sup>1</sup>

the BCY material, in particular, in different applications that involve very low humidity levels and low temperatures of operation. The most well-known is that of ammonia electrochemical synthesis [39–41], although many other processes concerning hydrogenation and de-hydrogenation reactions can also be considered

*Examples of dehydrogenation/hydrogenation reactions that can occur at very low humidity conditions.*

*Equilibrium constant for hydration of several perovskite proton conductors. Adapted from [9].*

*Analytical Chemistry - Advancement, Perspectives and Applications*

**Type Reaction** *Δ***H<sup>0</sup>**

**Dehydrogenations** 2CH4 gð Þ⇌C2H4 gð Þ þ 2H2 gð Þ 202

**Hydrogenations** C10H8 gð Þ þ 2H2 gð Þ⇌C10H12 gð Þ �134

6CH4 gð Þ⇌C6H6 gð Þ þ 9H2 gð Þ 89 C3H8 gð Þ⇌C3H6 gð Þ þ H2 gð Þ 124.3 iC4H10 gð Þ⇌iC4H8 gð Þ þ H2 gð Þ 122 C8H10 gð Þ⇌C8H8 gð Þ þ H2 gð Þ 117.6

C6H10 gð Þ þ H2 gð Þ⇌C6H12 gð Þ �120 C6H6 gð Þ þ 3H2 gð Þ⇌C6H12 gð Þ �207 N2 gð Þ þ 3H2 gð Þ⇌2NH3 gð Þ �109

that agree with these operating conditions (**Table 3**).

*Reproduced from [38] with permission from Elsevier.*

**5. Conclusions**

**64**

**Figure 12.**

**Table 3.**

Laura I.V. Holz, Vanessa C.D. Graça, Francisco J.A. Loureiro\* and Duncan P. Fagg Mechanical Engineering Department, Centre for Mechanical Technology and Automation, University of Aveiro, Aveiro, Portugal

\*Address all correspondence to: francisco.loureiro@ua.pt

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

) at

**298***=***kJ mol**�**<sup>1</sup>**
