Ambient ammonia synthesis via palladium-catalyzed electrohydrogenation of dinitrogen at low overpotential

Wang, Jun; Yu, Liang; Hu, Lin; Chen, Gang; Xin, Hongliang; Feng, Xiaofeng

doi:10.1038/s41467-018-04213-9

Cited by 665 publications

(498 citation statements)

References 45 publications

(36 reference statements)

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“…[33] In addition, since the concentration of newly produced NH 3 ⋅H 2 O in the electrolyte varied from 0.001 × 10 −3 to 0.01 × 10 −3 m, the NH 3 ⋅H 2 O concentration was assumed as 0.005 × 10 −3 m for calculating the equilibrium potential of this NRR half-reaction [33] In addition, since the concentration of newly produced NH 3 ⋅H 2 O in the electrolyte varied from 0.001 × 10 −3 to 0.01 × 10 −3 m, the NH 3 ⋅H 2 O concentration was assumed as 0.005 × 10 −3 m for calculating the equilibrium potential of this NRR half-reaction …”

Section: Quantification Of Hydrazinementioning

confidence: 99%

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

White

et al. 2019

Adv Funct Materials

167

121

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Developing cost-effective, high-performance nitrogen reduction reaction (NRR) electrocatalysts is required for the production of green and low-cost ammonia under ambient conditions. Here, a strategy is proposed to adjust the reaction preference of noble metals by tuning the size and local chemical environment of the active sites. This proof-of-concept model is realized by single ruthenium atoms distributed in a matrix of graphitic carbon nitride (Ru SAs/g-C 3 N 4 ). This model is compared, in terms of the NRR activity, to bulk Ru. The as-synthesized Ru SAs/g-C 3 N 4 exhibits excellent catalytic activity and selectivity with an NH 3 yield rate of 23.0 µg mg cat −1 h −1 and a Faradaic efficiency as high as 8.3% at a low overpotential (0.05 V vs the reversible hydrogen electrode), which is far better than that of the bulk Ru counterpart. Moreover, the Ru SAs/g-C 3 N 4 displays a high stability during five recycling tests and a 12 h potentiostatic test. Density functional theory calculations reveal that compared to bulk Ru surfaces, Ru SAs/g-C 3 N 4 has more facile reaction thermodynamics, and the enhanced NRR performance of Ru SAs/g-C 3 N 4 originates from a tuning of the d-electron energies from that of the bulk to a single-atom, causing an up-shift of the d-band center toward the Fermi level.can maximize metal utilization. Since SACs have unique catalytic sites, they usually exhibit a distinct catalytic selectivity as compared to their nanoclusters or nanoparticle counterparts. [2] For example, single atomic Pt immobilized in the surface of Ni nanocrystals shows a higher activity and chemoselectivity toward the hydrogenation of 3-nitrostyrene. [3] Isolated Co single-site catalysts anchored on a N-doped porous carbon nanobelt exhibits an excellent catalytic performance for oxidation of ethylbenzene with 98% conversion and 99% selectivity, whereas the Co nanoparticles are essentially inert. [4] Moreover, atomic Ni-anchored covalent triazine framework has a remarkable selectivity for the conversion of CO 2 to CO, with a Faradaic efficiency (FE) of > 90% over the range of −0.6 to −0.9 V versus the reversible hydrogen electrode (RHE). [5] In view of these reported works, it is evident that the size of metal particles is a key factor in determining their catalytic performance, and decreasing the size offers an intriguing opportunity to alter the activity and selectivity of these metal catalysts. SACs, as the limit of size reduction, hold great potential to achieve high activity and selectivity in catalytic reactions.Recently, the electrocatalytic N 2 reduction reaction (NRR) in aqueous electrolytes for synthesizing ammonia at ambient

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Section: Quantification Of Hydrazinementioning

confidence: 99%

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

White

et al. 2019

Adv Funct Materials

167

121

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“…Based on the calibration curves ( Figure S8, Supporting Information), we determined the corresponding NH 3 yields ( Figure 2b) and FEs ( Figure 2c). [44] The mass ratio of H 2 /NH 3 at various potentials is shown in Figure S10c (Supporting Information). Both NH 3 yields and FEs initially increase with potential being more negative.…”

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confidence: 99%

Electrocatalytic Hydrogenation of N₂ to NH₃ by MnO: Experimental and Theoretical Investigations

et al. 2018

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NH3 is a valuable chemical with a wide range of applications, but the conventional Haber–Bosch process for industrial‐scale NH3 production is highly energy‐intensive with serious greenhouse gas emission. Electrochemical reduction offers an environmentally benign and sustainable route to convert N2 to NH3 at ambient conditions, but its efficiency depends greatly on identifying earth‐abundant catalysts with high activity for the N2 reduction reaction. Here, it is reported that MnO particles act as a highly active catalyst for electrocatalytic hydrogenation of N2 to NH3 with excellent selectivity. In 0.1 m Na2SO4, this catalyst achieves a high Faradaic efficiency up to 8.02% and a NH3 yield of 1.11 × 10−10 mol s−1 cm−2 at −0.39 V versus reversible hydrogen electrode, with great electrochemical and structural stability. On the basis of density functional theory calculations, MnO (200) surface has a smaller adsorption energy toward N than that of H with the *N2 → *N2H transformation being the potential‐determining step in the nitrogen reduction reaction.

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“…This method allows the comparison of intrinsic activities of active sites and facilitates the identification and improvement of active-site structures for ENRR. [8][9][10][11][12][13][14][15][16][17][18] Mechanistic insights gained so far lean heavily on computational investigations, with relatively little experimental input and insufficient theory/experiment integration. [1] Despite more than acentury of optimization, the Haber-Bosch process remains energy and carbon intensive.…”

mentioning

confidence: 99%

“…[8][9][10][11][12][13][14][15][16][17][18] Mechanistic insights gained so far lean heavily on computational investigations, with relatively little experimental input and insufficient theory/experiment integration. [8][9][10][11][12][13][14][15][16][17][18] Mechanistic insights gained so far lean heavily on computational investigations, with relatively little experimental input and insufficient theory/experiment integration.…”

mentioning

confidence: 99%

“…To determine the density of surface Ns ites active in the ENRR on the VNO catalyst, we develop anovel quantitative isotopic exchange strategy.T his method is based on the understanding that the ENRR on VNO follows the MvK mechanism, [10,[21][22][23][24] with surface Na ctively involved in the catalytic turnovers.Itfollows that all surface Nsites involved in the ENRR would be replaced by 15 Nw hen the ENRR proceeds with 15 N 2 as the feed, leading to the formation of 14 NH 3 ( Figure 1A). Thus,t he amount of surface Ns ites involved in the ENRR could be determined by quantifying the amount of 14 NH 3 produced.…”

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confidence: 99%

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Quantification of Active Sites and Elucidation of the Reaction Mechanism of the Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride

et al. 2019

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Despite recent intense interest in the development of catalysts for the electrochemical nitrogen reduction reaction (ENRR), mechanistic understanding and catalyst design principles remain lacking. In this work, we develop as trategy to determine the density of initial and steady-state active sites on ENRR catalysts that follow the Mars-van Krevelen mechanism via quantitative isotope-exchange experiments. This method allows the comparison of intrinsic activities of active sites and facilitates the identification and improvement of active-site structures for ENRR. Combined with detailed density functional theory calculations,w es how that the ratelimiting step in the ENRR is likely the initial N Nb ond activation via the addition of ap roton and an electron to the adsorbed N 2 on the Nv acancies to form N 2 H. The methodology developed and mechanistic insights gained in this work could guide the rational catalyst design in the ENRR.Ammonia synthesis via the Haber-Bosch process is ap illar of modern agriculture,which converts the abundant but inert dinitrogen in the atmosphere to the key precursor of nitrogenbased fertilizers (N-fertilizers). [1] Despite more than acentury of optimization, the Haber-Bosch process remains energy and carbon intensive. [2][3][4][5][6][7] Distributed and modular ammonia synthesis via the electrochemical nitrogen reduction reaction (ENRR) at or close to ambient conditions,p owered by renewable electricity is an attractive alternative because it allows as-needed and on-site production of ammonia, and in turn N-fertilizers,from N 2 and water. [3] Widespread adoption of the ENRR for ammonia production could drastically reduce the carbon footprint of agricultural activities.ENRR is also compatible with the intermittencyo fr enewable energy sources,e .g., solar and wind energy,a sa mmonia and Nfertilizers can be produced and stored when renewable electricity is abundant or even in surplus.Ar ecent flurry of studies on the ENRR led to the discovery of many catalysts with remarkable ammonia production rates and selectivities. [8][9][10][11][12][13][14][15][16][17][18] Mechanistic insights gained so far lean heavily on computational investigations, with relatively little experimental input and insufficient theory/experiment integration. Forexample,reported ammonia production rates are typically normalized by the geometric area or electrochemical surface area determined by capacitance measurements, [19] which make the comparison of the intrinsic activity among different catalysts challenging. Catalyst development based on the comparison of (electrochemical) surface area normalized activities risks missing highly active structures/phases if they exist in low densities. Our recent work highlights this risk, as VN 0.7 O 0.45 ,rather than the bulk VN phase,inthe vanadium nitride (referred to as the oxygen-modified VN catalyst, or VNO below) is identified as the active phase. [10] Thus,i dentification and quantification of active sites in the ENRR are key to developing catalyst design principles. [20]...

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Ambient ammonia synthesis via palladium-catalyzed electrohydrogenation of dinitrogen at low overpotential

Cited by 665 publications

References 45 publications

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

Electrocatalytic Hydrogenation of N₂ to NH₃ by MnO: Experimental and Theoretical Investigations

Quantification of Active Sites and Elucidation of the Reaction Mechanism of the Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride

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Ambient ammonia synthesis via palladium-catalyzed electrohydrogenation of dinitrogen at low overpotential

Cited by 665 publications

References 45 publications

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

Tuning the Catalytic Preference of Ruthenium Catalysts for Nitrogen Reduction by Atomic Dispersion

Electrocatalytic Hydrogenation of N2 to NH3 by MnO: Experimental and Theoretical Investigations

Quantification of Active Sites and Elucidation of the Reaction Mechanism of the Electrochemical Nitrogen Reduction Reaction on Vanadium Nitride

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Electrocatalytic Hydrogenation of N₂ to NH₃ by MnO: Experimental and Theoretical Investigations