Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study Full article
| Conference |
XI International Conference Mechanisms of Catalytic Reactions 07-11 Oct 2019 , Сочи |
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| Journal |
Topics in Catalysis
ISSN: 1022-5528 , E-ISSN: 1572-9028 |
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| Output data | Year: 2020, Volume: 63, Number: 1-2, Pages: 12-23 Pages count : 12 DOI: 10.1007/s11244-020-01238-7 | ||
| Tags | Ammonia synthesis; Mo-based catalysts; Tailor-made active sites | ||
| Authors |
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| Affiliations |
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Funding (1)
| 1 | Federal Agency for Scientific Organizations | 0303-2016-0001 |
Abstract:
The strong Mo–N bond restrains the catalytic activity of metallic Mo in ammonia synthesis. In this study, the semi-empirical calculations in conjunction with the density functional theory calculations, Brønsted–Evans–Polanyi relationship and microkinetic modeling were used to evaluate the rate of ammonia synthesis on model active sites of Mo-based alloys, nitrides, and clusters with a modified Mo–N bond. It was found that active sites of binary alloys MoδMe1−δ (0 ≤ δ ≤ 1; Me = Co, Pt, Ir, Rh) show the synergetic behavior. The sites of ternary Mo3Me3N (Me = Mo, Co, Pt, Ir) and Mo2N-type nitrides revealed higher activities than sites on Mo planes due to an extra Mo bond with the lattice N atom. The sites of octahedral clusters Mo3Me3N (Me = Mo, Co, Ir, Pt) exhibited higher catalytic activity than the sites of nitrides because their Me–N bonds are weaker than Mo–N. It was also found that tetragonal Mo2Me2 (Me = Co, Pt, Ir) and bi-tetragonal clusters Mo3Me2 (Me = Co, Ir, Pt) are the best cases because their sites provide the optimal combination of local structure and thermodynamics. Catalytic activities of the most active sites, relative to the Fe–C7 center, were found to change in the row 18.4 (threefold site Mo2Ir1 in cluster Mo3Ir2), 7.3 (Mo2 in cluster Mo2Ir2), 3.9 (Mo2Pt1 in cluster Mo3Ir3N), 3.8 (M3 on alloy Mo0.78Ir0.22), 2.0 [Mo3Pt1 on the plane (100) of Mo3Pt3N], 0.57 [Mo3 on the plane (111) of Mo2N], and 0.03 [Mo4 on the plane Mo(110)–(1 × 2)]. The design of tailor-made catalytic sites suggested in this paper can probably be applied to other catalytic systems.
Cite:
Cholach A.
, Bryliakova A.
Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study
Topics in Catalysis. 2020. V.63. N1-2. P.12-23. DOI: 10.1007/s11244-020-01238-7 WOS Scopus РИНЦ AN OpenAlex
Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study
Topics in Catalysis. 2020. V.63. N1-2. P.12-23. DOI: 10.1007/s11244-020-01238-7 WOS Scopus РИНЦ AN OpenAlex
Dates:
| Published online: | Feb 15, 2020 |
| Published print: | Mar 1, 2020 |
Identifiers:
| Web of science: | WOS:000516240200002 |
| Scopus: | 2-s2.0-85079698195 |
| Elibrary: | 43248722 |
| Chemical Abstracts: | 2020:332497 |
| OpenAlex: | W3006191758 |