ScholarWorks@성균관대학교

초록

Electrides, in which anionic electrons are trapped in structural cavities, have garnered significant attention for exceptional functionalities based on their low work function. In low-dimensional electrides, a strong quantum confinement of anionic electrons leads to many interesting phenomena, but a severe chemical instability due to their open structures is one of the major disadvantages for practical applications. Here we report that one-dimensional (1D) dititanium sulfide electride exhibits an extraordinary stability originating from the surface self-passivation and consequent durability in bifunctional electrocatalytic activity. Theoretical calculations identify the uniqueness of the 1D [Ti2S]2+<middle dot>2e- electride, where multiple cavities form two distinct channel structures of anionic electrons. Combined surface structure analysis and in-situ work function measurement indicate that the natural formation of amorphous titanium oxide surface layer in air is responsible for the remarkable inertness in water and pH-varied solutions. This makes the [Ti2S]2+<middle dot>2e- electride an ideal support for a heterogenous metal-electride hybrid catalyst, demonstrating the enhanced efficiency and superior durability in both the hydrogen evolution and oxygen reduction reactions compared to commercial Pt/C catalysts. This study will stimulate further exploratory research for developing a chemically stable electride in reactive conditions, evoking a strategy for a practical electrocatalyst for industrial energy conversions.

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