# Heterogeneous Electro-Fenton-like Designs for the Disposal of 2-Phenylphenol from Water
## 4 Conclusions  
In the present study, the preparation of new catalysts and electrocatalysts using a transition metal as nickel supported in different clay and carbonaceous materials were successfully performed. Their evaluation on the degradation of a pollutant such as a fungicide 2-phenylphenol proved their efficiency and feasibility for their use in a heterogeneous Fenton based process. However, it is concluded the superiority of heterogeneous nickel electrocatalyst synthesised by the inclusion of nanofibers doped with nickel into carbon felt. The preparation of this electrocatalyst adding carbon black, nickel doped nanofibers and PTFE to the carbon felt increased significantly the potential to produce hydrogen peroxide (more than 4 times the unmodified carbon felt). In addition, the presence of the nickel catalyst on the cathode favoured the expected generation of hydroxyl radicals. The optimisation of the ratios among carbon black, nickel doped nanofibers and PTFE allowed concluding that the best production of hydrogen peroxide and the degradation yields were attained when the amount of carbon black and nanofibers were increased while the added PTFE decreased in the range evaluated. Moreover, an increase in the current efficiency and reduction in energy consumption was also achieved when a current intensity was 100 mA. Thus, the heterogeneous nickel electrocatalyst shows an excellent behaviour in the electro-Fenton process, with high hydrogen peroxide production, pollutant removal and stability. Summing up, the use of this new electrocatalyst can be an alternative to the current cathodes that increase the catalogue of catalysts offering advantages such as low leaching, high stability and pollutants removal. These open the possibility to develop more effective electrocatalysts extending the type of catalysts in the electro-Fenton process that helps to increase the viability of electro-advanced oxidation processes showing high potential to be used in the removal of pollutants. In a future more investigations are requested in order to evaluate its behaviour in the operation at high scale.  
**Author Contributions:** Conceptualization, E.R. and M.A.S.; methodology, E.R. and M.A.S.; formal analysis, A.F.-S. and E.R.; investigation, R.M.-T. and A.F.-S.; resources, M.P. and M.A.S.; data curation, A.F.-S. and E.R.; writing--original draft preparation, A.F.-S.; writing--review and editing, E.R. and M.A.S.; visualization, A.F.-S., M.P. and M.A.S.; supervision, M.P. and M.A.S.; project administration, M.P. and M.A.S.; funding acquisition, M.A.S. All authors have read and agreed to the published version of the manuscript.  
This research is part of the R&D Project CTM 2017-87326-R funded by 10.13039/5011000110 33/FEDER \"Una manera de hacer Europa\", Project PID2020-113667 GB-I00 funded by MCIN/ AEI/ 10.13039/501100011033 and PDC2021-121394-I00 funded by MCIN/ AEI/ 10.13039/501100011033 and by the European Union Next GenerationEU/PRTR, and Xunta de Galicia and European Regional Development Fund (ED431C 2021-43). Antia Fdez-Sanroman acknowledges the University of Vigo for training fellowships.  
**Informed Consent Statement:** Not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.