Reference #: 00517
Potential Applications:
The catalyst from this invention can be utilized as a cathode electrocatalyst in a PEM fuel cell. Such a fuel cell could be utilized for various applications, including power sources for electric vehicles. in such electric vehicles, high power output and stability are of great importance, and the cathode catalyst from this invention is advantageous in that regards.
Advantages and Benefits:
1. Has remarkably high catalytic activity
2. A high onset potential for ORR
3. Demonstrates current densities that are superior to the fuel cell performances with Platinum-free catalysts reported in literature
4. The optimized carbon composite catalyst shows no degradation of fuel cell performance even for 350hr of continuous operation
5. Exhibits a well-defined diffusion limiting current which is only observed in Pt-based catalysts
Problem:
The major impediment to the commercialization of proton exchange membrane (PEM) fuel cells is the low activity of electrocatalysts for the oxygen reduction reaction (ORR). Platinum (Pt) is considered the best cathode catalyst toward four-electron reduction of oxygen to water in acidic environments. It also shows the lowest over-potential and the highest stability. However Platinum remains an expensive metal of low abundance and it is thus of great importance to find Platinum-free alternatives for PEM fuel cells. Over the years several alternative have been explored but none of them fully meet the requirements due to the following deficiencies: (i) low catalytic activity (ii) Poor stability (iii) low sensitivity towards 4-electron reduction of oxygen to water (large amounts of hydrogen peroxide>5%) and (iv) high electronic resistance. Also they are typically synthesized through complex routes with expensive precursors. As such, a need currently exists for a low-cost, easily manufactured carbon-based catalyst having high activity, selectivity, and stability for ORR.
Invention Description:
In general, invention is directed toward a method of producing a composite carbon catalyst. The method includes oxidizing a carbon precursor (e.g. carbon black). Optionally, nitrogen functional groups can be added to the oxidized carbon precursor. Then, the oxidized carbon precursor is refluxed with a non-platinum transitional metal precursor in a solution. Finally, the solution is pyrolyzed at a temperature of at least 500 degrees Celsius.