Abstract
Electrochemical hydrogenation of nitrate to ammonia using renewable electricity is a promising route for sustainability but lacks catalysts that can deliver balanced selectivity, activity, and durability. Here, a new family of noble metal-free and high-performing Chevrel phase Ni2Mo6T8 (T = S, Se, and Te) catalysts that have similar structural and textural properties and differ presumably only in chalcogenide anion is systematically studied. The side-by-side comparisons allow the uncovering of the critical roles of chalcogenide anions in impacting kinetic activities and long-term durability. The incorporation of anions with larger size and smaller electronegativity from sulfide to selenide and telluride invokes stronger inhibition of the otherwise competing hydrogen evolution reaction (HER) and steers the hydrogenation toward the selective formation of ammonia, thus improving both Faradic selectivity and the turnover frequency to high levels of 99.4% and 21.5 s−1, respectively, on the Ni2Mo6Te8 catalyst. More significantly, the bulkier anion in the Ni2Mo6T8 catalyst kinetically inhibited the intercalation of electrolyte cations, a major degradation mechanism in the catalyst family examined here and delivered several times improved durability. Therefore, this study introduces novel active motifs for selective nitrate reduction and provides insights into the catalyst degradation mechanism and practical ways to improve durability.
Original language | English (US) |
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Article number | 2312079 |
Journal | Advanced Functional Materials |
Volume | 34 |
Issue number | 14 |
DOIs | |
State | Published - Apr 3 2024 |
Funding
This material was based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under award DE\u2010SC0023266. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for partial support of this research. Use of the Center for Nanoscale Materials, an Office of Science user facility, was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE\u2010AC02\u201006CH11357. The authors also thank the support provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DOE DE\u2010FG02\u201003ER15457 and DE\u2010SC0024448 to the Institute for Catalysis in Energy Processes (ICEP) at Northwestern University (Y.L., T.J.M). This work made use of the Keck\u2010II facility of Northwestern University's NUANCE Center, which had received support from the SHyNE Resource (NSF ECCS\u20102025633), the IIN, and Northwestern's MRSEC program (NSF DMR\u20101720139). The TEM studies were performed using the Themis in the UConn/Thermo Fisher Scientific Center for Advanced Microscopy and Materials Analysis (CAMMA).
Keywords
- Chevrel phase
- ammonia synthesis
- catalyst durability
- degradation mechanism
- electrocatalyst
- nitrate reduction
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Chemistry
- Biomaterials
- General Materials Science
- Condensed Matter Physics
- Electrochemistry