MoS2 Polymorphic Engineering Enhances Selectivity in the Electrochemical Reduction of Nitrogen to Ammonia
B. Rahmat Suryanto, D. Wang, L. Azofra, M. Harb, L. Cavallo, R. Jalili, D. Mitchell, M. Chatti, D. MacFarlane
ACS Energy Lett., 4, pp. 430-435, (2019)
The electrochemical N2 reduction reaction (NRR) offers a direct pathway to produce NH3 from renewable energy. However, aqueous NRR suffers from both low Faradaic efficiency (FE) and low yield rate. The main reason is the more favored H+ reduction to H2 in aqueous electrolytes. Here we demonstrate a highly selective Ru/MoS2 NRR catalyst on which the MoS2 polymorphs can be controlled to suppress H+ reduction. A NRR FE as high as 17.6% and NH3 yield rate of 1.14 × 10–10 mol cm–2 s–1 are demonstrated at 50 °C. Theoretical evidence supports a hypothesis that the high NRR activity originates from the synergistic interplay between the Ru clusters as N2 binding sites and nearby isolated S-vacancies on the 2H-MoS2 as centers for hydrogenation; this supports formation of NH3 at the Ru/2H-MoS2 interface.
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