## 3 Fe-MOF Synthesis
### Electrochemical Synthesis
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**MOF** & **Organic Ligand** & **Metal Source** & **Solvent** & **Procedure** & **Reference** \\ \hline \multirow{6}{*}{Fe\({}_{3}\)O\({}_{4}\)@MIL-100(Fe)} & \multirow{6}{*}{H\({}_{3}\)BTC} & \multirow{6}{*}{Fe\({}_{9}\)O\({}_{4}\) nanoparticles} & \multirow{6}{*}{Water} & H\({}_{3}\)BTC (1.0 g), Fe\({}_{9}\)O\({}_{4}\) microspheres (0.6 g) and water (12.5 mL) were reacted under microwave at 150 \({}^{\circ}\)C for 30 min (300 W). The solid was collected, washed and dried in a vacuum at 60 \({}^{\circ}\)C. \\ \hline \multirow{6}{*}{NH\({}_{2}\)-MIL-101(Fe)} & \multirow{6}{*}{NH\({}_{2}\)-BDC} & \multirow{6}{*}{FeCl\({}_{3}\):6H\({}_{2}\)O} & \multirow{6}{*}{DMF} & Dissolved FeCl\({}_{3}\):6H\({}_{2}\)O and acetic acid in DMF under sonication, followed by the addition of NH\({}_{2}\)-BDC. Then, it was placed in a microwave reactor (110 \({}^{\circ}\)C and 45 min). After that, the reactor was cooled down to room temperature, the precipitates were collected, cleaned and finally dried under vacuum at 60 \({}^{\circ}\)C overnight. \\ \hline \multirow{6}{*}{MIL-88A(Fe)} & \multirow{6}{*}{Fumaric acid} & \multirow{6}{*}{FeCl\({}_{3}\):6H\({}_{2}\)O} & The fumaric acid solution was added into a FeCl\({}_{3}\):6H\({}_{2}\)O solution (ratio molar 1:1). Then it was transferred into a microwave oven and heated for 3 min. Finally, the formed precipitate was collected, washed and dried at 70 \({}^{\circ}\)C. \\ \hline \multirow{6}{*}{Fe-MOFs} & \multirow{6}{*}{H\({}_{3}\)BTC} & \multirow{6}{*}{FeSO\({}_{4}\) 7H\({}_{2}\)O} & FeSO\({}_{4}\) 7H\({}_{2}\)O & FeSO\({}_{4}\) 7H\({}_{2}\)O and H\({}_{3}\)BTC (with a ratio molar of 1:5:1), stainless-steel balls and deionized water were combined in a tetafluoroethylene milling pot. Stir milling was performed at 200 rpm and the microwave oven was started concurrently for 40 min. The solid was filtered, washed, added to a beaker containing ethanol and then stirred with a magnetic stirrer for 3 h. This mixture was then filtered and dried. \\ \hline \multirow{6}{*}{NH\({}_{2}\)-MIL-88B(Fe)} & \multirow{6}{*}{NH\({}_{2}\)-BDC} & \multirow{6}{*}{FeCl\({}_{3}\):6H\({}_{2}\)O} & FeCl\({}_{3}\):6H\({}_{2}\)O, NH\({}_{2}\)-BDC and DMF ( molar ratio of 1:1:282) were mixed for 30 min and the solution was gassed by shaking in an ultrasonic bath for 5 min. Then, it was transferred into a Teflon autoclave and placed in a microwave oven (150 \({}^{\circ}\)C, 20 min and 600 W). The final product was purified and dried under a vacuum at 60 \({}^{\circ}\)C overnight. \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Examples of Fe-MOF that were synthesized by the microwave-assisted method. Based on what has been mentioned above, the great complexity of this method can be noted as well as the fact that not all metals have been used to synthesize MOFs. Of all those found, Cu-, Ti- and Zn-MOF are the ones that stand out [116]. Nevertheless, in recent years, more and more articles have started to use this method to obtain Fe-MOF. In fact, the first work that synthesized Fe-MOFs by this method was performed by [PERSON] et al. [117] in 2013. Since then, these MOFs have been gradually synthesized using this method. Therefore, it is relevant to mention some of these remarkable works. The first of these works was the one by [PERSON] et al. [118], in which they managed to synthesize Fe-MIL-101 and Fe-MIL-101-NH\({}_{2}\) in 30 min. In addition to being a fast method, they produced crystals of these MOFs with properties, such as a high surface area, comparable to those obtained by the solvothermal method, in which the operating conditions are more aggressive. Concerning the study of [PERSON] et al. [119], a metal-organic nanocomposite was fabricated by cathodic electrodeposition and the main novelty of this synthesis was that it was carried out in a single step.