ENHANCING OXYGEN EVOLUTION ACTIVITY OF NI, FE OXIDES USING NITROGEN PLASMA

• Main Author: Manopo, Jessie
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72994
• Institution: Institut Teknologi Bandung

The oxygen evolution reaction (OER) is a vital half-reaction for clean energy applications, such as water splitting and rechargeable metal-air batteries. However, this reaction suffers from sluggish kinetics due to high overpotential. To date, the most effective OER catalysts are RuO2 and IrO2. However, their relatively high-cost raw material hinders their practical application. Therefore, we need to develop alternative materials to replace these noble metal-based catalysts. The search for non-noble metal electrocatalysts has been extensively studied. In this study, Ni, and Fe oxides dispersed on carbon framework have been synthesized. The metal-organic framework precursors were synthesized using the coprecipitation method. The precursors were then calcined at 600oC to obtain the corresponding metal oxides supported on a carbon framework. In this study, the effect of the Ni to Fe ratio has been studied. The best performing OER catalyst is Ni, Fe oxides/C (1:1). This sample possesses the highest NiFe2O4 content which has a theoretical eg occupancy of ~1.3. Which is close to the ideal OER electrocatalyst (~1.25). The nitrogen plasma treatment was done and shown to enhance the electrocatalytic performance of the samples, increasing its ORR onset potential significantly by 0.09V. This is due to etching and destroying ?-orbital conjugation of chemically stable sp2 hybridization. The nitrogen plasma treatment can also dope the carbon framework and add more pyridinic-N and pyrrolic-N sites which also increase its electrocatalytic activity due to the conjugation of ?-orbital and the nitrogen lone pair electron. Lastly, the effect of different ligands has also been studied. The N-doped carbon framework showed superior performance (higher power density) compared to bare carbon due to its increased conductivity.