Efficient Hydrogen Evolution Reaction Catalysis in Alkaline Media by All-in-One MoS2 with Multifunctional Active Sites

Abstract

MoS2 becomes an efficient and durable nonprecious-metal electrocatalyst for the hydrogen evolution reaction (HER) when it contains multifunctional active sites for water splitting derived from 1T-phase, defects, S vacancies, exposed Mo edges with expanded interlayer spacings. In contrast to previously reported MoS2-based catalysts targeting only a single or few of these characteristics, the all-in-one MoS2 catalyst prepared herein features all of the above active site types. During synthesis, the intercalation of in situ generated NH3 molecules into MoS2 sheets affords ammoniated MoS2 (A-MoS2) that predominantly comprises 1T-MoS2 and exhibits an expanded interlayer spacing. The subsequent reduction of A-MoS2 results in the removal of intercalated NH3 and H2S to form an all-in-one MoS2 with multifunctional active sites mentioned above (R-MoS2) that exhibits electrocatalytic HER performance in alkaline media superior to those of all previously reported MoS2-based electrocatalysts. In particular, a hybrid MoS2/nickel foam catalyst outperforms commercial Pt/C in the practically meaningful high-current region (>25 mA cm(-2)), demonstrating that R-MoS2-based materials can potentially replace Pt catalysts in practical alkaline HER systems.