# Catalytic Evaluation of Hafnium Modified SiO\({}_{2}\) for the Dehydration of Alcohols
## 4 Conclusions  
Mesoporous silicon oxide with a structure similar to MCM-41 was prepared from sodium silicate, and its surface acidity was modified by adding 3.6 wt.% fhavium as well as sulfate ions. However, the introduction of sulfate ions from sulfuric acid caused the hexagonal structure, which is characteristic of MCM-41 materials, to collapse as evidenced by X-ray analysis at low angles. However, synergy between sulfate ions and hafnium was evidenced by the high catalytic activity obtained in the decomposition of ethanol and methanol. These materials showed resistance to deactivation during the reaction, making them a good option for the decomposition of bio-alcohols into high-value-added products. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline  & & **T = 300 \({}^{\circ}\)C** & & **T = 325 \({}^{\circ}\)C** & & **T = 350 \({}^{\circ}\)C** & \\ \hline
**Catalyst** & **XA * (\%)** & \(S_{C_{2}^{\star}}\)** ** **(\%)** & \(S_{E}\)*** **(\%)** & \(\mathbf{X_{A}}\)** **(\%)** & \(S_{C_{2}^{\star}}\)** **(\%)** & \(S_{E}\)** **(\%)** & \(\mathbf{X_{A}}\)** **(\%)** & \(S_{C_{2}^{\star}}\)** **(\%)** & \(S_{E}\)** **(\%)** \\ \hline SiO\({}_{2}\) & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ \hline
3.6 Hf/SiO\({}_{2}\) & 50 & 86 & 14 & 80 & 96 & 4 & 94 & 99 & 1 \\ \hline
12 SHf/SiO\({}_{2}\) & 100 & 100 & 0 & - & - & - & - & - & - \\ \hline \end{tabular}
* Conversion. ** Selectivity to ethylene. *** Selectivity to diethyl ether.  
\end{table} 
Table 3: Catalytic activity of the materials. **Author Contributions:** Conceptualization, H.E.B. and R.G.A. ; formal analysis, H.E.B. and R.G.A. ; investigation, H.E.B., R.G.A., L.A.G.S., J.A.C.G. and F.P.D. ; methodology, H.E.B. and R.G.A. ; software, F.P.D. and L.A.G.S. ; supervision, R.G.A. ; validation, R.G.A. and L.A.G.S. ; writing--original draft, H.E.B. ; writing--review and editing, R.G.A., L.A.G.S., J.A.C.G. and F.P.D. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by the National Council for the Humanities, Science and Technology (CONAHCYT, in Spanish), through the postdoctoral fellowship (231186) and the projects IPN-SIP-20231352, IPN-SIP-20232246. As well as the support of the laboratory and socio-technological observatory of permaculture, micro-nanomaterials and scientific and humanistic innovation, Higher Technological Institute of Naranjos, Technological Institute of Ciudad Madero, Project Future Team, Joint Agency Cooperation Glocal. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Not applicable. **Acknowledgments:** We want to express our gratitude to [PERSON], [PERSON], and [PERSON] from the Advanced Materials Research Center for their support in the characterization of the materials, as well as to Cinthya Cristal Casanova Juarez. **Conflicts of Interest:** The authors declare no conflict of interest. * (18) [PERSON]; [PERSON]; [PERSON]; [PERSON] Dehydration of Ethanol over Zeolites, Silica Alumina and Alumina: Lewis Aidity, Bronsted Acidity and Confinement Effects. _Appl. Catal. Gen._**2015**, _493_, 77-89. [CrossRef]
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