Straightforward engineering of porous C3N4/Fe3O4 electrocatalyst for oxygen reduction reaction in alkaline medium

Abstract

Recently, biodegradable polymer-derived and heteroatom-doped carbon-Fe3O4 electrocatalysts have attracted a lot of attention due to their ease of manufacturing, biocompatibility, ease of use, environmental friendliness, and ability to induce porosity. Furthermore, as compared to conventional polymers, the nitrogen-containing functional groups in the chitosan-based biopolymer generate cross-linking between the biopolymer and metal sources. We developed a highly stable and hierarchical N-doped carbon-Fe3O4 electrocatalyst by pyrolysis of the membrane produced from the chitosan gel with 2 (w/v)% of ferric chloride hexahydrate (FeCl3.6H2O) at 700 °C, 800 °C, and 900 °C, respectively. The produced materials were used to execute an electrocatalytic oxygen reduction process under a 0.1 M potassium hydroxide (KOH) electrolyte solution. Similar experiments were also carried out at 3 and 4 (w/v)% of FeCl3.H2O solutions under the pyrolysis of 800 °C and 900 °C. The working electrodes prepared at 3 and 4 (w/v)% of FeCl3.H2O with chitosan under 800 °C and 900 °C have demonstrated much improved electrocatalytic activity as compared with the electrodes prepared at 2 (w/v)% of FeCl3.H2O with chitosan under various pyrolysis temperatures. These results manifest the effective role of the addition of Fe to the chitosan to activate and enhance the electrocatalytic activity for oxygen reduction reaction (ORR). These results give a broad opportunity to explore the electrocatalyst for further applications.