AcknowledgementsThe authors would l

Acknowledgements
The authors would like to express their gratitude to the Dr. R.
Zanella Specia (CCADET, UNAM), Dr. C.L. Peza-Ledesma (CFATAUNAM),
and I.Q. E. Fragoso (IIM-UNAM) for performing SBET, FT-IR
and thermal analysis, respectively. The authors greatly acknowledge
Prof. J.L.G. Fierro (ICP-CSIC, Madrid, Spain) for stimulating
discussion and performing XPS analysis. Financial support by
PROMEP (Project UAQ-PTC-190) is gratefully acknowledged.