The global rapidly-growing energy demand and environmental concerns stimulates the lasting research interests to develop renewable energy alternatives worldwide. The electrochemical oxygen reduction and evolution are key steps in determining the performance of various next-generation energy conversion and storage devices, such as fuel cells, metal-air batteries, and water electrolysis et. al. The commercialization of these technologies prominently depends on the development of low-cost high-performance electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) to replace the state-of-the-art precious metal-based catalysts. In this presentation, several reasonable ways will be introduced for rational designing new non-precious metal nanocatalysts with high electrocatalytic activities and superior stability for ORR and OER. By focusing on the creation and enrichment of highly active sites and simultaneously considering the mass transfer and electron transportation, we have developed a series of efficient low-cost nanocatalysts. The further improvement on performance can be achieved by introducing transition metal into these nanocatalysts and modulating the nanostructures and the electronic structure of active centers. Furthermore, understanding the origin of high activity of these electrocatalysts is critical for developing efficient non-precious metal catalysts but still challenging. For example, we developed a highly active Fe-N-C ORR catalyst containing Fe-Nx coordination sites and Fe/Fe3C nanocrystals. By intensively investigating the correlations of the composition and structure of catalyst with the electrochemical performance, it was discovered that the high ORR activity of such Fe-N-C catalysts should originated from that Fe/Fe3C nanocrystals boost the activity of Fe-Nx. For OER catalysts, it was interestingly found that the electronic modulation on active center and the crystallinity of the catalysts significantly affect the OER activity. These new findings open opportunities for the rational design and bottom-up synthesis of cost-effective efficient ORR and OER electrocatalysts for energy conversion and storage applications.

Designing efficient non-precious metal nanocatalysts for oxygen reduction and evolution

254th National Meeting (2017)

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