Highly Active Nitrogen-Doped Carbon Metal Oxide Hybrid Composites for Oxygen Reduction Reaction

Fuel Cells have been considered as clean and promising energy-converting devices due to their high efficiency and low/ zero emission. However, the cost and reliability are two challenges for their commercialization. The high cost of components, which is mainly due to the use of platinum-based catalysts for oxygen reduction reaction (ORR), is attracted extensive research works on finding alternatives synthesized from low-cost and more abundant compounds.

Recent studies on pyrolyzed metal inserted nitrogen doped carbon based catalysts for ORR show high performance, at level of platinum-based catalyst, and promising durability. Herein, we report synthesis, characterization and electrochemical analysis of hybrid composites consisting of N-doped (predominantly pyridinic N- and pyrrolic) carbons and transition metal (cobalt and iron) oxides for the ORR. XPS and XRD studies revealed the active nitrogen groups and crystallographic phases of nanoparticles. The composite catalysts were prepared via a solvothermal pyrolysis process. They exhibit high catalytic activity with the 4e or 2e reaction pathways and superior stability to Pt/C for ORR in alkaline media.

Figure 1. Cyclic voltammograms of hybrid composite of iron oxide inserted N-doped carbon nanomaterials in O₂-saturated solution of 0.1 M NaOH at 20 ±2 °C under different rotation rates.( Sweep rate = 10 mVs^-1)