**Author details**

**Figure 12.** Impedance for copper and different coating components immersed in H<sup>2</sup>

**Figure 11.** Impedance for stainless steel and different coating components immersed in H<sup>2</sup>

PANI, and the lowest impedance value (15 ohms·cm<sup>2</sup>

in the impedance modules obtained [30].

In a similar way as before, the coating systems were applied, but this time in a copper metal substrate. A similar response was obtained (**Figure 12**), where the Nyquist plots show a semicircle with lower impedance resistance values as compared with stainless steel samples; followed by a straight line with different slopes associated to the coating protection and mass

The high frequency impedance obtained was for the GO, followed by Cu, PANI, GO/

sample. The highest impedance modulus (low frequency) seen is for the bare copper sample

istered is for the coating GO/PANI/AuNp system (**Figure 12b**). The mass transfer is reflected

) lowering its values for PANI, GO, and GO/PANI, and the smallest value reg-

(b) Bode plots.

and (b) Bode plots.

88 Graphene Oxide - Applications and Opportunities

(650 ohms·cm2

transport (**Figure 12a**) [29].

SO<sup>4</sup>

SO<sup>4</sup>

1 M solution (a) Nyquist

1 M solution (a) Nyquist and

) for the GO/PANI/AuNp coating

Carmina Menchaca-Campos<sup>1</sup> , Elsa Pereyra-Laguna<sup>1</sup> , César García-Pérez<sup>1</sup> , Miriam Flores-Domínguez<sup>1</sup> , Miguel A. García-Sánchez<sup>2</sup> and Jorge Uruchurtu-Chavarín<sup>1</sup> \*

\*Address all correspondence to: juch25@uaem.mx

1 Centro de Investigación en Ingeniería y Cciencias Aplicadas-(IICBA), Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, Mexico

2 Departamento de Química, UAM-Iztapalapa, Mexico, DF, Mexico
