**Acknowledgements**

The authors wish to acknowledge the Consejo Nacional de Ciencia y Tecnología de los Estados Unidos Mexicanos (CONACyT) for its financial support to develop this project and to Magyar Földtani és Geofizikai Intézet for financial support under project TÉT\_12\_MX‐1‐ 2013‐0010. M. Pérez‐Corona is grateful to CONACyT for her scholarship to get her Ph. D. in Electrochemistry.
