Amino-grafted water-soluble maghemite nanocrystals synthesized by deep eutectic solvents electrolysis: Investigation of the formation mechanism

Benefiting from the hydrophilicity and modifiability, aminated iron oxide nanoparticles play significant roles in the construction of magnetically responsive functional materials, and are then widely used in the field of biomedicine and water purification. Using the deep eutectic solvent (DES) composed of urea and choline chloride as an electrolyte, amino-grafted water-soluble maghemite (gamma-Fe2O3) nanocrystals have been synthesized by organic electrolysis (DES-electrolysis). In the present work, the DES containing ferrous ions is used as the electrolyte to verify whether magnetite (Fe3O4) can be prepared by that organic electrolysis strategy. The results show that, regardless of the presence or absence of ferrous ions in the DES-based electrolyte, the resulting nanocrystals are maghemite rather than magnetite. The synthesized amino-grafted gamma-Fe2O3 nanoparticles can also be highly and stably dispersed in water. The present work deepens the understanding of the formation mechanism of amino-grafted water-soluble maghemite nanocrystals synthesized by DES-electrolysis.

Automated summary

Benefiting from hydrophilicity and modifiability, aminated iron oxide nanoparticles are widely used in the construction of magnetic functional materials in the fields of biomedicine and water purification. In this study, amino-grafted water-soluble maghemite nanocrystals were synthesized using deep eutectic solvents (DES) as an electrolyte for organic electrolysis (DES-electrolysis). The findings demonstrate that the resulting nanocrystals are maghemite, regardless of the presence or absence of ferrous ions in the DES-based electrolyte. This work provides a deeper understanding of the formation mechanism of amino-grafted water-soluble maghemite nanocrystals synthesized by DES-electrolysis.