NH3 Production Research Articles

Bimetallic Cu11Ag3 Nanotips for Ultrahigh Yield Rate of Nitrate-to-Ammonium.

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH3 production and NO3- removal but suffers from low NH3 yield rate (<1.20 mmol h-1 cm-2). We present bimetallic Cu11Ag3 nanotips with tailored local environment and tip-enhanced effects, which achieve an ultrahigh NH3 yield rate of 2.36 mmol h-1 cm-2 at a low applied potential of -0.33 V vs. RHE, a high Faradic efficiency (FE) of 98.8%, and long-term operation stability at 1800 mg-N L-1 NO3-, outperforming most of the recently reported catalysts. At a NO3- concentration as low as 15 mg-N L-1, it still delivers a high FE of 86.9% and an NH3 selectivity of 93.8%. Operando ATR-FTIR spectra, finite-element method, and DFT calculations reveal that the Cu11Ag3 exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H2 formation, while its tip-enhanced enrichment promoting NO3- accumulation.

Bimetallic Cu11Ag3 Nanotips for Ultrahigh Yield Rate of Nitrate‐to‐Ammonium

Electrochemical reduction of nitrate to ammonia (NRA) offers a sustainable approach for NH3 production and NO3‐ removal but suffers from low NH3 yield rate (&lt;1.20 mmol h‐1 cm‐2). We present bimetallic Cu11Ag3 nanotips with tailored local environment and tip‐enhanced effects, which achieve an ultrahigh NH3 yield rate of 2.36 mmol h‐1 cm‐2 at a low applied potential of ‐0.33 V vs. RHE, a high Faradic efficiency (FE) of 98.8%, and long‐term operation stability at 1800 mg‐N L‐1 NO3‐, outperforming most of the recently reported catalysts. At a NO3‐ concentration as low as 15 mg‐N L‐1, it still delivers a high FE of 86.9% and an NH3 selectivity of 93.8%. Operando ATR‐FTIR spectra, finite‐element method, and DFT calculations reveal that the Cu11Ag3 exhibits reduced adsorption energy barrier of *N intermediates, favorable water dissociation for *H generation and high energy barrier for H2 formation, while its tip‐enhanced enrichment promoting NO3‐ accumulation.

Bifunctional sludge-derived redox carbon dots with photoelectron storage and delivery properties for ammonia production by photosensitized Shewanella oneidensis MR-1

Combining the light-harvesting capabilities of photosensitizers with microbial catalysis shows great potential in solar-driven biomanufacturing. However, little information is available about the effects of photosensitizers on the photoelectron transport during the dissimilatory nitrate reduction to ammonium (DNRA) process. Herein, redox carbon dots (CDs-500) were prepared from sludge via the pyrolysis-Fenton reaction and then used to construct a photosynthetic system with Shewanella oneidensis MR-1. The MR-1/CDs-500 photosynthetic system showed a 5.9-fold increase in ammonia production (4.9 mmol(NH3)·g−1(protein)·h−1) with a high selectivity of 94.0 %. The photoelectrons were found to be stored in CDs-500 and transferred into the cells. During the inward electron transport, the intracellular CDs-500 could be used as the direct photoelectron transfer stations between outer membrane cytochrome c and DNRA-related enzymes without the involvement of CymA and MtrA. This work provides a new method for converting waste into functional catalysts and increases solar-driven NH3 production to a greater extent.

Phosphorization of α-Fe2O3 Boosts Active Hydrogen Mediated Electrochemical Nitrate Reduction to Ammonia.

Inexpensive iron-based materials are considered promising electrocatalysts for nitrate (NO3 -) reduction, but their catalytic activity and spontaneous corrosion remain challenges. Here, the α-Fe2O3 active surface is reconstructed by gradient phosphorization to obtain FePx with higher electrochemical activity. FeP2.0 optimizes the adsorption energy of NO3 - and its reduction intermediates, meanwhile promote the generation of active hydrogen (*H) but inhibit its generation of H2. More importantly, Fe and P can serve as binding sites for NO3 - and *H, respectively, which improves the electron utilization of NO3 - deoxygenation and the efficiency of the subsequent hydrogenation for the selective synthesis of NH3. 91.7% NO3 - conversion rate is achieved for the reduction of 100mL 200mg L-1 NO3 --N, 99.3% ammonia (NH3 selectivity (yield of 1.79 mg h-1 cm-2), and 91.4% Faraday efficiency in 3 h. The high-purity solid NH4Cl is finally extracted by gas extraction and vacuum distillation (81.4% recovery). This study provides new insights and strategies for the conversion of NO3 - to NH3 products over iron-based electrocatalysts.

Highly-selective Electrocatalytic Reduction of NO to NH3 using Cu Embedded WS2 Monolayer as Single-atom Catalyst: A DFT Study.

Electrocatalytic nitric oxide reduction reaction (NORR) is a promising method for generating NH3. However, developing a NORR catalyst for NH3 synthesis with low cost and high efficiency is still challenging. We here report a series of single-atom catalysts (SACs), designed by embedding nine different transition metals from Sc to Cu in S-vacant WS2 monolayer (TM@WS2), and investigate the electrocatalytic performance for NORR process using the dispersion-corrected density functional theory (DFT) calculations. Among them, Cu-based SACshows a strong binding to the WS2 surface and high selectivity towards NORR process, and also it greatly inhibits the competing hydrogen evolution reaction (HER). Through ab initio molecular dynamics (AIMD) simulations, the thermal stability of SAC is assessed and found no structure deformation even at 500 K temperature. All possible reactive pathways including distal and alternating mode at both N- and O-end configurations for NH3 production were explored. We predicted that the Cu@WS2 SAC exhibits remarkable catalytic activity and selectivity with lowest limiting potential of -0.41 V via the N-alternating pathway. Our study emphasize that the transition metal dichalcogenide (TMDC) based SACs are potential candidates for converting NO to NH3, and this opens a new avenue in designing NORR catalysts with high catalytic performance.

CoNiOOH nanosheets array enables highly effective value-added chemicals production via nitrite and sulfide electrolysis

Here, we show that the CoNiOOH nanosheets array can be applied for catalyzing nitrite reduction and sulfide oxidation reactions (NO2RR and SOR) simultaneously, realizing NH3 production and synchronous desulfuration. As a result, the catalyst achieves a maximal Faradic efficiency of 93 % with the corresponding yield rate of 14.6mg h−1 cm−2 for NH3 production and high robustness over 4 consecutive cycles. Beyond that, it could trigger the SOR with a low potential of 0.65 V vs RHE to reach 100 mA cm−2, far lower than that needed for the water oxidation (1.62 V vs RHE). More importantly, the coupling system composed of NO2RR and SOR could realize value-added products on both sides. Theoretical and experimental analyses validate that Ni regulates the electronic structure of Co site, which optimizes the activation and adsorption of reactants and intermediates, and thus reduce the energy barriers, accounting for the performance enhancement.

Regulating RuxMoy Nanoalloys Anchored on Porous Nitrogen-Doped Carbon via Domain-Confined Etching Strategy for Neutral Efficient Ammonia Electrosynthesis.

Neutral electrochemical nitrate (NO3-) reduction to ammonia involves sluggish and complex kinetics, so developing efficient electrocatalysts at low potential remains challenging. Here, we report a domain-confined etching strategy to construct RuxMoy nanoalloys on porous nitrogen-doped carbon by optimizing the Ru-to-Mo ratio, achieving efficient neutral NH3 electrosynthesis. Combining in situ spectroscopy and theoretical simulations demonstrated a rational synergic effect between Ru and Mo in nanoalloys that reinforces *H adsorption and lowers the energy barrier of NO3- hydrodeoxygenation for NH3 production. The resultant Ru5Mo5-NC surpasses 92.8% for NH3 selectivity at the potential range from -0.25 to -0.45 V vs RHE under neutral electrolyte, particularly achieving a high NH3 selectivity of 98.3% and a corresponding yield rate of 1.3 mg h-1 mgcat-1 at -0.4 V vs RHE. This work provides a synergic strategy that sheds light on a new avenue for developing efficient multicomponent heterogeneous catalysts.

Promotion of La2O3 on Pd/Al2O3 three-way catalyst for passive selective catalytic reduction operation

For three-way catalysts (TWC) applied in lean burn gasoline engines for passive selective catalytic reduction (pSCR) operation, besides the conversion efficiency of HC/CO/NO, the production of NH3 is also an important concern. In this work, La2O3 was introduced into the Pd/Al2O3 catalyst system, the influence on its TWC performance for pSCR operation was investigated, and the physicochemical properties were characterized by a range of techniques. The results reveal that the introduced La2O3 mainly interacts with Al2O3 by preferentially anchoring to the tetra-coordinated Al sites on the surface. When the catalyst is modified by appropriate amount of La2O3 (4 wt%), higher dispersion of Pd species, larger amount of Pd2+ and active oxygen species are achieved, which well contributes to improved low-temperature reduction ability and NH3 desorption property of the catalyst. As a consequence, excellent catalytic conversions of HC/CO/NO are obtained, and meanwhile, higher concentration of NH3 is generated, making the modified catalyst more promising for pSCR operation.

Flame dynamic insights into pollutant production characteristics of NH[formula omitted]/H[formula omitted]/air combustion during turbulent flame–wall interaction

A turbulent premixed NH3/H2/air flame with Damköhler number Da = 0.004 has been simulated using direct numerical simulations (DNS) with detailed chemistry. The flame is propagating in a fully-developed turbulent channel flow with friction Reynolds number Reτ = 313. The global and local production speeds of NO, N2O and NH3 have been analyzed. Special attention is paid on the flame dynamic insights into the pollutant production characteristics during the flame–wall, flame–turbulence and flame–flame interaction process. Finally, important findings have been concluded: (1) The unburned NH3 is reduced in the turbulent case due to the smaller quenching distance; (2) The N2O consumption speed would decrease just before flame quenching on the wall in the turbulent case, due to the thickened flame thickness, which is contradictory to the laminar case; (3) Effect of flame curvature on pollutant production speeds should be combined with the effect of flame surface density; (4) Low Damköhler number flame tends to produce more N2O and less NO, due to the more frequent flame–flame interaction events. These findings would help to better understand the pollutant production characteristics of turbulent premixed NH3/H2/air flames in lab-scale burners with strong flame–wall interactions.Novelty and Significance StatementThe novelty of this research is summarized into 3 points: (1) It is, to our knowledge the first time, pollutant production characteristics are investigated in detail for the premixed NH3/H2/air flame propagating in a fully developed turbulent boundary layer; (2) The effects of flame–wall, flame–turbulence and flame–flame interactions, the underlying reasons and controlling mechanisms are investigated in detail, which has not yet been (comprehensively) done in previous studies; (3) Novel and important findings have been concluded for the wall effects, turbulence effects (including flame curvature and surface density function effects) and flame–flame interaction effects. Some of these findings have never been reported before, but important for the comprehensive understanding of the pollutant production characteristics. It is significant because understanding the turbulence and wall effects on NO, N2O and NH3 production characteristics in the premixed NH3/H2/air flames is crucial for the future clean combustion energy system design.

MOF‐on‐MOF Heterostructured Electrocatalysts for Efficient Nitrate Reduction to Ammonia

AbstractElectrocatalytic nitrate reduction reaction (NO3−RR) is an important route for sustainable NH3 synthesis and environmental remediation. Metal–organic frameworks (MOFs) are one family of promising NO3−RR electrocatalysts, however, there is plenty of room to improve in their performance, calling for new design principles. Herein, a MOF‐on‐MOF heterostructured electrocatalyst with interfacial dual active sites and build‐in electric field is fabricated for efficient NO3−RR to NH3 production. By growing Co‐HHTP (HHTP=2,3,6,7,10,11‐hexahydroxytriphenylene) nanorods on Ni‐BDC (BDC=1,4‐benzenedicarboxylate) nanosheets, experimental and theoretical investigations demonstrate the formation of Ni−O−Co bonds at the interface of MOF‐on‐MOF heterostructure, leading to dual active sites tailed for NO3−RR. The Ni sites facilitate the adsorption and activation of NO3−, while the Co sites boost the H2O decomposition to supply active hydrogen (Hads) for N‐containing intermediates hydrogenation on adjacent Ni sites, cooperatively reducing the energy barriers of NO3−RR process. Together with the accelerated electron transfer enabled by built‐in electric field, remarkable NO3−RR performance is achieved with an NH3 yield rate of 11.46 mg h−1 cm−2 and a Faradaic efficiency of 98.4 %, outperforming most reported MOF‐based electrocatalysts. This work provides new insights into the design of high‐performance NO3−RR electrocatalysts.

MOF-on-MOF Heterostructured Electrocatalysts for Efficient Nitrate Reduction to Ammonia.

Electrocatalytic nitrate reduction reaction (NO3 -RR) is an important route for sustainable NH3 synthesis and environmental remediation. Metal-organic frameworks (MOFs) are one family of promising NO3 -RR electrocatalysts, however, there is plenty of room to improve in their performance, calling for new design principles. Herein, a MOF-on-MOF heterostructured electrocatalyst with interfacial dual active sites and build-in electric field is fabricated for efficient NO3 -RR to NH3 production. By growing Co-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) nanorods on Ni-BDC (BDC=1,4-benzenedicarboxylate) nanosheets, experimental and theoretical investigations demonstrate the formation of Ni-O-Co bonds at the interface of MOF-on-MOF heterostructure, leading to dual active sites tailed for NO3 -RR. The Ni sites facilitate the adsorption and activation of NO3 -, while the Co sites boost the H2O decomposition to supply active hydrogen (Hads) for N-containing intermediates hydrogenation on adjacent Ni sites, cooperatively reducing the energy barriers of NO3 -RR process. Together with the accelerated electron transfer enabled by built-in electric field, remarkable NO3 -RR performance is achieved with an NH3 yield rate of 11.46 mg h-1 cm-2 and a Faradaic efficiency of 98.4 %, outperforming most reported MOF-based electrocatalysts. This work provides new insights into the design of high-performance NO3 -RR electrocatalysts.

Strategy of constructing D-A structure and accurate active sites over graphitic carbon nitride nanowires for high efficient photocatalytic nitrogen fixation

Constructing photocatalysts for the stable and efficient production of NH3 is of excellent research significance and challenging. In this paper, the electron acceptor 5-amino-1,10-phenanthroline (AP) is introduced into the electron-donor graphitic carbon nitride (CN) framework by a simple heated copolymerization method to construct a donor–acceptor (D-A) structure. Subsequently, the phenanthroline unit is coordinated with transition metal Fe3+ ions to obtain the photocatalyst Fe(III)-0.5-AP-CN with better nitrogen fixation performance, and the average NH3 yield can reach 825.3 μmol g−1 h−1. Comprehensive experimental results and theoretical calculations show that the presence of the D-A structure can induce intramolecular charge transfer, effectively separating photogenerated electrons and holes. The Fe active sites can improve the chemisorption energy for N2, enhance the N-Fe bonding, and better activate the N2 molecule. Therefore, the synergistic effect between the construction of the D-A structure and the stably dispersed Fe active sites can enable CN to achieve high-performance N2 reduction to produce NH3.

Cu/CuxO/Graphdiyne Tandem Catalyst for Efficient Electrocatalytic Nitrate Reduction to Ammonia.

The electrocatalytic reduction reaction of nitrate (NO3 -) to ammonia (NH3) is a feasible way to achieve artificial nitrogen cycle. However, the low yield rate and poor selectivity toward NH3 product is a technical challenge. Here a graphdiyne (GDY)-based tandem catalyst featuring Cu/CuxO nanoparticles anchored to GDY support (termed Cu/CuxO/GDY) for efficient electrocatalytic NO3 - reduction is presented. A high NH3 yield rate of 25.4mg h-1 mgcat. -1 (25.4mg h-1 cm-2) with a Faradaic efficiency of 99.8% at an applied potential of -0.8V versus RHE using the designed catalyst is achieved. These performance metrics outperform most reported NO3 - to NH3 catalysts in the alkaline media. Electrochemical measurements and density functional theory reveal that the NO3 - preferentially attacks Cu/CuxO, and the GDY can effectively catalyze the reduction of NO2 - to NH3. This work highlights the efficacy of GDY as a new class of tandem catalysts for the artificial nitrogen cycle and provides powerful guidelines for the design of tandem electrocatalysts.

Evaluating the potential of green hydrogen, ammonia and urea in Lao PDR energy transitions.

Abstract We report the results of a systematic evaluation of the redeployment of surplus hydropower electricity to produce green hydrogen (H2), ammonia (NH3) and urea (CH4N2O) in Lao PDR. Participatory system mapping (PSM) workshops convened across multiple Lao PDR ministries revealed both direct and indirect opportunities and risks as probable consequences of green H2, NH3 and urea production. Participants debated and prioritized green urea fertilizer to replace “grey” imports; coal co-firing; and fuel cells as the products that contribute to the opportunities and manage the risks identified by the PSM process. Techno-economic modelling indicates the levelized cost of urea (US$467/tonne) is competitive with Thai imports, associated with opportunities for trading carbon offsets. Carbon credits were not sufficient to offset the additional co-firing costs of coal generation, and fuel cells are a likely future enterprise. A targeted capacity building and training program was a central pillar of a systems-based dissemination strategy to develop necessary technical and planning skills and community and awareness raising. The collated research results represent an integrated foundation to draft the Lao PDR National green H2 and NH3 road map and action plan, and a cross-sectoral revision of energy transition development plans.

Spatial-confined effect of CuOx microneedles bundles on TiO2 nanotubes: Reinforcing the adsorption and enrichment of ultralow concentration nitrate for efficient NH3 electrosynthesis

Nitrate (NO3−) Electroreduction to produce NH3 offers an alternative approach to sustainable production of NH3. Yet it remains challenging to simultaneously improve the adsorption and enrichment of low-concentration NO3−. Here, bundles of CuOx microneedles on TiO2 nanotubes (NTs) were developed by a spatial-confined electrodeposition strategy, achieving 87.7 % or 98.4 % NH3 FE at −0.25 V or −0.45 V vs RHE in 2 or 10 mM NO3− electrolytes, respectively. Both in-situ spectroscopy and finite element analysis simulation demonstrated that CuOx microneedle bundles and its interface between TiO2 NTs not only greatly improve the enrichment of low concentration NO3− and its derived-NO2− and the diffusion of NH3 product, but also enhance the adsorption of NO2− and H2O to facilitate the hydrodeoxygenation of NO3− as well as inhibit hydrogen evolution reaction competition. This work will provide a promising avenue to develop electrocatalysts to realize efficient catalytic conversion of reactants at low concentrations.

Bio-inspired catalysts for enhanced N₂ electroreduction to NH3: Architecting molecular screening interfaces via active sites microenvironment engineering

The electrochemical nitrogen reduction reaction (ENRR) promises a sustainable route for ammonia (NH3) production but faces hurdles from competing hydrogen evolution reaction (HER) and insufficient N2 concentration. Drawing inspiration from Tropical Lizards’ unique mechanism of creating a thin air layer on their hydrophobic skin, we modify the catalyst-water interface using alkyl thiols of different chain lengths on VS2 (Cx-VS2, x = 4,8,12). This novel approach suppresses HER and increases N2 availability. Among the tailored catalysts, C8-VS2 exhibits superior ENRR performance, with an ammonia yield of 58.43 μg h−1 mgcat−1 and a Faradaic efficiency of 34.69 % that surpasses unmodified VS2 (21.05 μg h−1 mgcat−1 and 8.87 %). Supporting measurements and density functional theory (DFT) calculations confirm the pivotal role of the modified interface in optimizing NH3 production. Our findings offer fresh perspectives for designing efficient electrocatalysts via tailoring interface microenvironments, with potential implications for various applications.

Reduced spinel oxide ZnCo2O4 with tetrahedral Co2+ sites for electrochemical nitrate reduction to ammonia and energy conversion

Electrocatalytic NO3− reduction to ammonia (NRA) at ambient conditions emerges as an appealing solution for green ammonia synthesis. In this work, we prepared a reduced Co-based spinel oxide for efficient ammonia synthesis and energy conversion. The in-depth structural characterization and electrochemical evaluation revealed thatthe introduction of Zn and reduction treatment led to the formation of electron-deficient tetrahedrally coordinated Co2+ sites. The resulting R-ZnCo2O4 exhibited remarkable NH3 production capacity with high NH3 selectivity of 92.2 %, FE of 92.3 %, and yield rate of 5.35 mgNH3 h−1 cm−2 (ca. 26.75 mgNH3 h−1 mgcat−1) under a low potential of − 0.3 V vs. RHE. The NRA pathway on R-ZnCo2O4 was further elucidated through DFT calculations and in situ characterizations. The high NRA efficiency of R-ZnCo2O4 was further explored in a Zn − NO3− battery, which was specified by an open circuit voltage of 1.46 V and a peak-power density of 1.40 mW cm−2, demonstrating its promising application for sustainable energy supply and green ammonia synthesis.

Insights into the multiple active sites in Bi-Co bimetallic oxide for a deeper understanding of nitrate electroreduction to ammonia

The electrochemical nitrate reduction reaction (NO3RR) is a promising approach for nitrate removal and NH3 production at ambient conditions. The development of various types of efficient electrocatalysts, especially bimetallic oxides with the advantages of superior durability and excellent catalytic activity, have become a research focus. However, the analysis of active sites for bimetallic oxide catalysts either emphasizes the role of bimetallic interactions or focuses on the role of oxygen vacancies (OVs), resulting in a lack of thoroughness. Herein, a Bi-Co bimetallic oxide (BCO) was constructed for NO3RR, illustrating 1.5∼7.8 folds higher NH3 yield rate than those of commercial single metal oxide (Bi2O3, Co3O4). The NO3RR pathway by BCO was explored according to H* capture test, DEMS, and isotope labeling experiment. An in-situ Raman test showed the structure evolution of BCO during NO3RR, and therefore the catalytic sites of BCO were further identified according to physical characteristics before and after NO3RR. Results suggest that Bi0, OVs and amorphous Co oxide as the real active sites play a vital role in nitrate electroreduction. Furthermore, research on 25 articles also indicates the presence of multiple catalytic sites in bimetallic oxides for NO3RR. This study provides a new and comprehensive insight into the active sites identification for the type of bimetallic oxide NO3RR electrocatalysts.

Radiocatalytic ammonia synthesis from nitrogen and water.

The development of alternative methods to the Haber-Bosch process for ammonia (NH3) synthesis is a pressing and formidable challenge. Nuclear energy represents a low-carbon, efficient and stable source of power. The harnessing of nuclear energy to drive nitrogen (N2) reduction not only allows 'green' NH3 synthesis, but also offers the potential for the storage of nuclear energy as a readily transportable zero-carbon fuel. Herein, we explore radiocatalytic N2 fixation to NH3 induced by γ-ray radiation. Hydrated electrons (e- aq) that are generated from water radiolysis enable N2 reduction to produce NH3. Ru-based catalysts synthesized by using γ-ray radiation with excellent radiation stability substantially improve NH3 production in which the B5 sites of Ru particles may play an important role in the activation of N2. By benefitting from the remarkable penetrating power of γ-ray radiation, radiocatalytic NH3 synthesis can proceed in an autoclave under appropriate pressure conditions, resulting in an NH3 concentration of ≤5.1mM. The energy conversion efficiency of the reaction is as high as 563.7mgNH3·MJ-1. This radiocatalytic chemistry broadens the research scope of catalytic N2 fixation while offering promising opportunities for converting nuclear energy into chemical energy.

Spatially Separated Cu/Ru on Ordered Mesoporous Carbon for Superior Ammonia Electrosynthesis from Nitrate over a Wide Potential Window.

Nitrate (NO3-) in wastewater poses a serious threat to human health and the ecological environment. The electrocatalytic NO3- reduction to ammonia (NH3) reaction (NO3-RR) emerges as a promising carbon-free energy route for enabling NO3- removal and sustainable NH3 synthesis. However, it remains a challenge to achieve high Faraday efficiencies at a wide potential window due to the complex multiple-electron reduction process. Herein, spatially separated dual-metal tandem electrocatalysts made of a nitrogen-doped ordered mesoporous carbon support with ultrasmall and high-content Cu nanoparticles encapsulated inside and large and low-content Ru nanoparticles dispersed on the external surface (denoted as Ru/Cu@NOMC) are designed. In electrocatalytic NO3-RR, the Cu sites can quickly convert NO3- to adsorbed NO2- (*NO2-), while the Ru sites can efficiently produce active hydrogen (*H) to enhance the kinetics of converting *NO2- to NH3 on the Cu sites. Due to the synergistic effect between the Cu and Ru sites, Ru/Cu@NOMC exhibits a maximum NH3 Faradaic efficiency (FENH3) of approximately 100% at -0.1 V vs reversible hydrogen electrode (RHE) and a high NH3 yield rate of 1267 mmol gcat-1 h-1 at -0.5 V vs RHE. Finite element method (FEM) simulation and electrochemical in situ Raman spectroscopy revealed that the mesoporous framework can enhance the intermediate concentration due to the in situ confinement effect. Thanks to the Cu-Ru synergistic effect and the mesopore confinement effect, a wide potential window of approximately 500 mV for FENH3 over 90% and a superior stability for NH3 production over 156 h can be achieved on the Ru/Cu@NOMC catalyst.