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Corresponding Author

Jun-jie GE(gejj@ciac.ac.cn);
Chang-peng LIU(liuchp@ciac.ac.cn);
Wei XING(zmzhang@jlu.edu.cn)

Abstract

The development of highly active and stable catalysts toward oxygen reduction reaction (ORR) has been facing severe challenges. In recent years, pyrolytic M-N-C catalysts and metal-organic framework derived materials made the performance of non-noble metal catalysts greatly improved, however, the molecular and atomic level understanding in the reaction active sites and the mechanism are still lacking. Here, we summarize the recent research progress made in the Changchun Institute of Applied Chemistry. We present a microporous metal-organic-framework confined strategy toward the preferable formation of ORR catalysts. Firstly, we studied the active site and proposed a new active site structure for the Fe-N-C catalyst, which is helpful for the development of new catalyst. The M-N-C catalyst was carefully regulated and the best synthesis method was discussed; Secondly, a highly efficient binuclear Co2N5 catalyst was developed, which performs approximately 12 times higher activity than the conventional CoN4 site and shows unprecedented catalytic activity in an acidic electrolyte with the half-wave potential of 0.79 V, presenting the best one among the Co-N-C catalysts, and a more efficient FeCo diatomic catalyst was synthesized under the guidance of theoretical calculation, indicating that the FeCoN5—OH site enables the ORR onset potential and half-wave potential up to 1.02 and 0.86 V (vs. RHE), respectively, with an intrinsic activity over 20 times higher than the single-atom FeN4 site; Finally, to overcome the stability problem caused by Fenton reaction, we developed novel single atomic Cr and Ru catalysts, showing low Fenton reaction activity, higher activity and stability after the accelerated degradation test for 20000 cycles, with the half-wave potentials being dropped only 15 and 17 mV, respectively, much lower than 31 mV of Fe-N-C catalysts. This offers a new way to solve the problem in catalyst application. We believe that upon further understanding in the active sites and the continuous development of new catalyst, the non-noble metal catalysts in PEMFCs will become truly applicable, which aids to solve the increasingly serious energy crisis environment.

Graphical Abstract

Keywords

oxygen reduction reaction, metal-nitrogen-carbon catalyst, active site, atmotic dispersion, fuel cell

Publication Date

2020-08-28

Online Available Date

2020-06-03

Revised Date

2020-05-29

Received Date

2020-05-07

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