An Innovative Approach to Produce Magnetite Nanoparticles Synthesized by a Combined Electrochemical and Chemical Coprecipitation Method and their Electrochemical Monitoring

Abstract

The synthesis of magnetite nanoparticles ( F e 3 O 4 NPs) remains an interesting topic for the electrochemistry community. However, currently, there is still some lack of information related to their production. For instance, the basic reaction stages involved in electrochemical synthesis and their dependence on the oxygen concentration, the optimal polarization potential and the current density applied are parameters that should be agreed upon. In this work, a simple and innovative approach is presented not only to efficiently produce F e 3 O 4 NPs but also their side products in a selective manner by controlling the dissolved oxygen in the reaction media. The approach includes a two-step methodology. First, F e ( O H ) 2 is electrochemically produced. As a second step, the production of magnetite nanoparticles is carried out through a purely chemical method with different amounts of atmospheric oxygen, as oxidizing agent. Thus, it is demonstrated that the F e 3 O 4 NPs are produced by chemical reactions rather than by an electrochemical process. Furthermore, through the acquisition of both open circuit potential and pH values as a function of time, it is possible to determine the optimal parameters, i.e., dissolved atmospheric oxygen and pH of the media, to selectively obtain not only F e 3 O 4 NP but also byside products such as hematite, maghemite, akageneite and lepidocrocite.