An ultra-low platinum loading ORR electrocatalyst with high efficiency: Synergistic effects of Pt and Fe-N-C support

The oxygen reduction reaction (ORR) is crucial in fuel cells and zinc-air batteries. However, the high cost and limited availability of platinum (Pt) catalysts have hindered the commercialization of these energy devices. Developing cost-effective, high-performance, low-platinum catalysts has become a key strategy for improving ORR activity.

This study presents a novel approach to synthesizing an ultra-low platinum loading ORR electrocatalyst. The researchers prepared Fe-N-C precursors via the polyaniline (PANI) pathway, which ensures uniform distribution of Fe-N-C species and facilitates the subsequent adsorption of platinum ions. This leads to the formation of Pt-Fe bimetallic alloys. The synergistic interaction between Pt and Fe-N-C sites enhances the homogeneous dispersion of Pt and the formation of smaller particle sizes, thereby improving the intrinsic activity and stability of the catalyst.

The Pt/Fe-N-C catalyst, with an ultra-low Pt loading of just 1.79 wt%, demonstrates remarkable performance. It exhibits a doubling of mass activity compared to conventional catalysts. In zinc-air batteries, this catalyst achieves an impressive peak power density of 200 mW/cm². The catalyst also shows excellent durability, with only a 20 mV drop in half-wave potential after 10,000 cycles in alkaline conditions and no significant shift in half-wave potential after 10,000 cycles in acidic conditions.

This research offers valuable insights into optimizing the structure of platinum-based catalysts to enhance their catalytic activity and stability. The ultra-low platinum loading ORR electrocatalyst developed in this study has the potential to significantly reduce the cost of fuel cells and zinc-air batteries, making them more viable for commercial applications. The findings pave the way for the development of more efficient and cost-effective energy conversion devices.