Surface-Engineered Cobalt Oxide Nanowires as Multifunctional Electrocatalysts for Efficient Zn-Air Batteries-Driven Overall Water Splitting

Surface-Engineered Cobalt Oxide Nanowires as Multifunctional Electrocatalysts for Efficient Zn-Air Batteries-Driven Overall Water Splitting

Energy Storage Materials

10.1016/j.ensm.2019.05.046

closed

https://doi.org/10.1016/j.ensm.2019.05.046

Baoshan Tang, Jing Yang, Zongkui Kou, Le Xu, Hwee Leng Seng, Yannan Xie, Albertus D. Handoko, Xixia Liu, Zhi Wei Seh, Hiroyo Kawai, Hao Gong, Weifeng Yang

03 June 2019

Tang, B., Yang, J., Kou, Z., Xu, L., Seng, H. L., Xie, Y., Handoko, A. D., Liu, X., Seh, Z. W., Kawai, H., Gong, H. & Yang, W. 2019. Surface-engineered cobalt oxide nanowires as multifunctional electrocatalysts for efficient Zn-Air batteries-driven overall water splitting. Energy Storage Materials, 23, 1-7.

Active sites engineering of electrocatalysts is an essential step to improve their intrinsic electrocatalytic capability for practical applications. Here, we demonstrate a facile surface phosphidisation into cobalt oxide (Co3O4) nanowires to boost their active sites, where phosphorus substitution for oxygen atoms greatly increases the number of cobalt (II) cations (Co2þ) and oxygen vacancies (VO) active sites. First-principles calculations combined with high-resolution X-ray photoemission spectroscopy, electron spin resonance and X-ray absorption spectroscopy characterization identify that the phosphorus heteroatoms and VO alter the electron density of surface Co atoms in Co3O4 nanowires, resulting in the conversion of cobalt (III) cations (Co3þ) to more active Co2þ.Asa result, the multifunctional catalysts of Co3O4 nanowires exhibit superior catalytic performance in overall water splitting with a low cell voltage of 1.61 V at 10mA cm 2 and zinc-air batteries with a high open-circuit voltage of 1.41 V and power density of 72.1mWcm 2. Particularly, two-series-connected Zn-air batteries powerfully drive an electrolyzer system without any additional electrode materials. These experimental and theoretical findings offer a promising approach to constructing active sites in non-precious metal catalysts for efficient and stable electrocatalytic activity.

PublisherCopyrights

This work was supported by Singapore Ministry of Education Academic Research Fund Tier 2 MOE2016-T2-1-049 and grant R-284-000-157-112. W.Y. acknowledges the support from Institute of Materials Research and Engineering (IMRE), A*STAR (Agency for Science, Technology, and Research). Z.W.S. acknowledges the support of the Singapore National Research Foundation (NRFNRFF2017-04) and IMRE, A*STAR (IMRE/17-1R1211).

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Institute of Materials Research and Engineering