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Corresponding Author

Zi-dong WEI(zdwei@cqu.edu.cn)

Abstract

Transition metal oxides (TMOs) based catalysts have become the most promising catalysts to be employed in anion exchange membrane fuel cell for the sluggish oxygen reduction reaction (ORR). However, their ORR activity is still far from that of the Pt-based catalysts. Therefore, it is important to develop high performance TMO based catalysts. Electrical conductivity and intrinsic activity have been regarded as the two keys to affect the ORR activity of the TMOs based catalysts. In this review, we focused on the recent progresses in the fundamental viewpoints on the electrical conductivity and intrinsic activity of the TMOs based ORR catalysts. Accordingly, the strategies to enhance the electrical conductivity and intrinsic activity are also summarized. The electrical conductivity could be reinforced in two ways. On the one hand, by coupling with the conductive materials, the external electrical conductivity of TMOs based catalysts could be elevated strongly. On the other hand, the intrinsic electrical conductivity of TMOs based catalysts could be enhanced by introducing oxygen vacancies or doping other cations or anions into TMOs. For the intrinsic activity of the TMOs based ORR catalysts, the crystal structure modulation for TMOs based catalysts is presented. Besides, the ORR descriptor of TMOs based catalysts, which is important for the future catalysts design, is also concluded in this review. And the conclusions and some future perspectives are also outlined. Although many strategies have been proposed to evaluate the electrical conductivity of TMOs based catalysts, there is still room for the further enhancement when the durability of TMOs based catalysts has been taken into consideration. And the ORR mechanism of TMOs based catalysts also should be further explored. Hence, there is a challenging but desired avenue for the development of the high performance TMOs based catalysts which are expected to be applied into anion exchange membrane fuel cell.

Graphical Abstract

Keywords

transition-metal-oxides, oxygen reduction reaction, fuel cell

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Publication Date

2018-10-28

Online Available Date

2018-07-23

Revised Date

2018-07-10

Received Date

2018-06-28

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