Water- And acid-stable self-passivated dihafnium sulfide electride and its persistent electrocatalytic reaction

Se Hwang Kang, Se Hwang Kang, Joonho Bang, Kyungwha Chung, Chandani N. Nandadasa, Gyeongtak Han, Subin Lee, Kyu Hyoung Lee, Kimoon Lee, Yanming Ma, Yanming Ma, Sang Ho Oh, Seong Gon Kim, Young Min Kim, Young Min Kim, Sung Wng Kim, Sung Wng Kim

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Abstract

Electrides have emerged as promising materials with exotic properties, such as extraordinary electron-donating ability. However, the inevitable instability of electrides, which is caused by inherent excess electrons, has hampered their widespread applications. We report that a self-passivated dihafnium sulfide electride ([Hf2S]2+ 2e-) by double amorphous layers exhibits a strong oxidation resistance in water and acid solutions, enabling a persistent electrocatalytic hydrogen evolution reaction. The naturally formed amorphous Hf2S layer on the cleaved [Hf2S]2+ 2e- surface reacts with oxygen to form an outermost amorphous HfO2 layer with ∼10-nm thickness, passivating the [Hf2S]2+ 2e- electride. The excess electrons in the [Hf2S]2+ 2e- electride are transferred through the thin HfO2 passivation layer to water molecules under applied electric fields, demonstrating the first electrocatalytic reaction with excellent long-term sustainability and no degradation in performance. This self-passivation mechanism in reactive conditions can advance the development of stable electrides for energy-efficient applications.

Original languageEnglish
Article numberEABA7416
JournalScience Advances
Volume6
Issue number23
DOIs
Publication statusPublished - 2020 Jun

All Science Journal Classification (ASJC) codes

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    Kang, S. H., Kang, S. H., Bang, J., Chung, K., Nandadasa, C. N., Han, G., Lee, S., Lee, K. H., Lee, K., Ma, Y., Ma, Y., Oh, S. H., Kim, S. G., Kim, Y. M., Kim, Y. M., Kim, S. W., & Kim, S. W. (2020). Water- And acid-stable self-passivated dihafnium sulfide electride and its persistent electrocatalytic reaction. Science Advances, 6(23), [EABA7416]. https://doi.org/10.1126/sciadv.aba7416