Adjustment of active sites in catalytic ammonia synthesis over metal alloys and clusters: A theoretical study

Cholach, A. R.

doi:10.1016/j.apcata.2018.06.017

Cited by 4 publications

(13 citation statements)

References 71 publications

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“…[106] Several theoretical studies suggest alloying Ru with other metals (Pt, Rh) will improve the B 5 site necessary for efficient N 2 activation. [107] Goddard et al predicted that Rh doping with Fe would increase the TOF for NH 3 synthesis by a factor of 3 compared to Fe (111). [108] Doping Rh with other elements such as Pt, Cu, Pd may also dramatically improve the TOF compared to Rh.…”

Section: Intermetallic/alloymentioning

confidence: 99%

“…[108] Doping Rh with other elements such as Pt, Cu, Pd may also dramatically improve the TOF compared to Rh. [107,108]…”

Section: Intermetallic/alloymentioning

confidence: 99%

“…Ru−Fe supported on MgO exhibited higher activity than Ru/MgO and Fe/MgO with resistance to N and H poisoning at high pressure [106] . Several theoretical studies suggest alloying Ru with other metals (Pt, Rh) will improve the B 5 site necessary for efficient N 2 activation [107] . Goddard et al.…”

Section: Different Class Of Catalysts For Nh3 Synthesismentioning

confidence: 99%

“…predicted that Rh doping with Fe would increase the TOF for NH 3 synthesis by a factor of 3 compared to Fe (111) [108] . Doping Rh with other elements such as Pt, Cu, Pd may also dramatically improve the TOF compared to Rh [107,108] …”

Section: Different Class Of Catalysts For Nh3 Synthesismentioning

confidence: 99%

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Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

2020

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Section: Intermetallic/alloymentioning

confidence: 99%

“…[108] Doping Rh with other elements such as Pt, Cu, Pd may also dramatically improve the TOF compared to Rh. [107,108]…”

Section: Intermetallic/alloymentioning

confidence: 99%

Section: Different Class Of Catalysts For Nh3 Synthesismentioning

confidence: 99%

Section: Different Class Of Catalysts For Nh3 Synthesismentioning

confidence: 99%

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Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

2020

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“…We have shown an outlook of binary alloys as possible active catalysts for ammonia synthesis [32,33]. The present study considers Mo-based alloys, nitrides and clusters as other candidates for the formation of advanced catalytic sites by modifying the strength of the surface-nitrogen bond and activity in the hydrogenation of atomically adsorbed nitrogen.…”

Section: Introductionmentioning

confidence: 99%

Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study

Cholach

Bryliakova

2020

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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 Mo δ Me 1−δ (0 ≤ δ ≤ 1; Me = Co, Pt, Ir, Rh) show the synergetic behavior. The sites of ternary Mo 3 Me 3 N (Me = Mo, Co, Pt, Ir) and Mo 2 N-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 Mo 3 Me 3 N (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 Mo 2 Me 2 (Me = Co, Pt, Ir) and bi-tetragonal clusters Mo 3 Me 2 (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-C 7 center, were found to change in the row 18.4 (threefold site Mo 2 Ir 1 in cluster Mo 3 Ir 2 ), 7.3 (Mo 2 in cluster Mo 2 Ir 2 ), 3.9 (Mo 2 Pt 1 in cluster Mo 3 Ir 3 N), 3.8 (M 3 on alloy Mo 0.78 Ir 0.22 ), 2.0 [Mo 3 Pt 1 on the plane (100) of Mo 3 Pt 3 N], 0.57 [Mo 3 on the plane (111) of Mo 2 N], and 0.03 [Mo 4 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.

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Unraveling the Enhanced N₂ Activity on CuNi Alloy Catalysts for Ammonia Production: Experiments, DFT, and Statistical Analysis

Agharezaei,

Tomohiro,

Kobayashi

et al. 2024

J. Phys. Chem. C

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One of the main challenges in designing catalysts for ammonia synthesis is to create active sites on the surface of the catalyst that prefers to reduce the strong N 2 molecule despite its highly stable structure. Binary alloys have been demonstrated as potential ammonia synthesis catalysts in the literature. However, for binary alloys to be commercially viable, one needs to improve their catalytic activity for N 2 reduction by strategically manipulating the several unique active sites present on their surface. Herein, by using computational tools, we created five different compositions of Cu x Ni 1−x (0.5 ≤ x ≤ 0.9) alloys via special quasi-random structure (SQS) and genetic algorithm (GA). The alloy with about 50% of Cu and 50% of Ni is predicted to have the highest catalytic activity based on the shift of the d-band center toward the Fermi level. We then synthesized MgO-supported Cu 0.5 Ni 0.5 nanoparticles and compared their activity for ammonia synthesis with that of Ni/MgO and Cu/MgO. It was found that the MgO-supported Cu 0.5 Ni 0.5 alloy possesses 21 times higher activity than Cu/MgO and 3 times higher than Ni/MgO for ammonia synthesis, confirming the computational results. To demonstrate the impact of alloying on the catalytic activity, we further investigated all the possible unique sites on the surface of the Cu 0.5 Ni 0.5 alloy for nitrogen reduction reaction (NRR) via density functional theory (DFT). The investigation of the 96 unique active sites on the Cu 0.5 Ni 0.5 surface demonstrated that the position and concentration of Ni atoms near each investigated adsorption site have a linear correlation with the adsorption energy of the N 2 . Along with the structural and electronic properties of the active sites modified by Ni, orientation of the N 2 molecule also plays an important role in determining the activity of the CuNi catalyst. These findings not only explained the notable increase in the activity of CuNi catalysts compared to the pure metals for NH 3 synthesis but also offered critical insights required to tailor the specific surface environment of CuNi catalysts for NRR. This knowledge can serve as a foundation for further developments in designing binary alloy catalysts for sustainable ammonia synthesis.

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Adjustment of active sites in catalytic ammonia synthesis over metal alloys and clusters: A theoretical study

Cited by 4 publications

References 71 publications

Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study

Unraveling the Enhanced N₂ Activity on CuNi Alloy Catalysts for Ammonia Production: Experiments, DFT, and Statistical Analysis

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Adjustment of active sites in catalytic ammonia synthesis over metal alloys and clusters: A theoretical study

Cited by 4 publications

References 71 publications

Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

Recent Advances in Heterogeneous Catalysis for Ammonia Synthesis

Design of Active Centers in Ammonia Synthesis on Mo-Based Catalysts: A Theoretical Study

Unraveling the Enhanced N2 Activity on CuNi Alloy Catalysts for Ammonia Production: Experiments, DFT, and Statistical Analysis

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Unraveling the Enhanced N₂ Activity on CuNi Alloy Catalysts for Ammonia Production: Experiments, DFT, and Statistical Analysis