Prepartion And Properties Of Non-Noble Metal Electrocatalysts With Imidazole-Containing Polymer As Nitrogen Sources

Proton exchange membrane fuel cell (PEMFC) as a new chemical power supply, is expected to replace the thermal power with high energy consumption and high pollution generation. Electrocatalysts as a core component of PEMFC effect the performance and cost of PEMFC, it plays a crucial role in a commercial production. At present, the most common of the electrocatalysts is Pt-based catalysts, but Pt-based catalysts have their restrictions such as high cost and low stability. Therefore, the main goal now is to explore cheap non-noble metal electrocatalysts. In this paper, we selected moCNTs as the carbon source, PyPBI, AdPBI, PPI and melamine as the nitrogen source to prepare the electrocatalysts with high catalytic activity and high stability. The main work is as follows:1. Selecting moCNTs as the carbon source, PyPBI or AdPBI as the nitrogen source to prepare the electrocatalysts of moCNTs/PyPBI(Co) and moCNTs/AdPBI(Co) by a two-step method consisting of solution co-blending method and pyrolyzation. The results showed that the nitrogen source and the temperature were important factors influencing the catalytic activity, the maximum ORR onset potential of the electrocatalyst was 0.78V(vs. RHE) when selected PyPBI as nitrogen source and the temperature was 850?, we attributed it to product pyridinic nitrogen during pyrolysis process, next complexing of pyridinic N and cobalt to form Co-N active site.2. Selecting moCNTs as the carbon source, PyPBI and melamine as dual nitrogen source to prepare the electrocatalysts of moCNTs/PyPBI/Mela(Co) by a two-step method consisting of solution co-blending method and pyrolyzation. The results showed that the maximum ORR onset potential of the electrocatalyst was 0.85V(vs. RHE) when the temperature was 800? and the ratios of moCNTs/PyPBI(Co) precursors and melamine was 1:2.3. Selecting moCNTs as the carbon source, PPI and melamine as dual nitrogen source to prepare the electrocatalysts of moCNTs/PPI/Mela(Co) by a two-step method consisting of solution co-blending method and pyrolyzation. The results showed that the maximum ORR onset potential of the electrocatalyst was 0.91 V(vs. RHE) when the temperature was 700? and the ratios of moCNTs/PPI(Co) precursors and melamine was 1:2, the weight percentage of the pyridinic nitrogen was 49.2% and the average electron transfer numbers was 3.70, it showed that the electrocatalyst complete the ORR through the 4e~-reduction pathway involving H2O as a product, which provides a good explanation for its high electrocatalytic activity.