Electrochemical Nitrogen Reduction Research Articles

Electrochemical dinitrogen to ammonia reduction at a nickel(ii) site: an easy access to an air-stable catalyst

The electrochemical nitrogen reduction reaction (NRR) for producing NH3 (ammonia) is a suitable alternative to the Haber–Bosch process due to its eco-friendly and non-polluting nature.

Electrocatalytic nitrogen reduction reaction: recent advances in dual-atom catalysts for sustainable ammonia production

This review provides an overview of the recent developments in dual-atom catalysts (DACs) for the electrochemical nitrogen reduction reaction.

Flatland materials for photochemical and electrochemical nitrogen fixation applications: from lab-door experiments to large-scale applicability

Flatland materials were meticulously surveyed to explore their functionality in photochemical and electrochemical nitrogen reduction reaction applications. New insights are presented for pilot-scale NRR operations via 2D materials.

Vanadium doped B5N3 and B7N5 monolayer as single atom catalyst for nitrogen reduction reaction – a first-principles study

The Haber-Bosch process, commonly used for ammonia synthesis, can be replaced by the electrochemical nitrogen reduction reaction (NRR), which offers a more environmentally conscious and sustainable approach. However, developing electrocatalysts with low potential, high selectivity, and fast reaction kinetics remains challenging. In the current work, we have theoretically calculated the potential of V@B5N3 and V@B7N5 (V = Vanadium) material which serves as an electrocatalyst for NRR using density functional theory (DFT) simulations. Our results reveal that the monolayer of V@B7N5 exhibits remarkable catalytic activity and effectively suppresses the hydrogen evolution reaction at an overpotential of 0.13 V. Furthermore, the potential-determining step involving the conversion of *N2-*N2H demonstrates a favourable energy barrier, indicating facile kinetics. The V@B7N5 monolayer shows promising selectivity, with an anticipated ammonia production efficiency of 99%. These findings open avenues for employing single-atom catalysts under ambient conditions to synthesise ammonia, offering a potential solution for sustainable ammonia production.

Electrochemical Analysis on Transition Metal Nitride Catalysts for Nitrogen Reduction Reaction

A versatile and sustainable process for ammonia production is needed to ensure a sustainable future for the growing global population, both with regards to fertilizer production as well as energy carrier. Theoretical simulations of transition metal nitride catalysts have demonstrated the possibilityof a nitrogen reduction reaction catalysis cycle on four transition metal nitrides, CrN, VN, ZrN and NbN.[1,2] Reproducible and reliable research and development approaches in the direction of electrochemical reduction of nitrogen towards ammonia are therefore of importance. An operando ammonia quantification methodology for electrochemical catalysis studies has been developed in-house and recently published [3]. Allowing for automatic, quantitative detection of aqueouos ammonia at the ppb level, within minutes from the sample preparation. We have now analyzed all four theoretically proposed TMNs, as well as rutile Niobium oxynitride (NbON) of several stochiometries as thin films on a conductive electrode substrate in ambient environment and aqueouos electrochemical system [3,4].Electrochemical analysis and ammonia quantification suggest NbON of specific stochiometry and ZrN to be promising catalyst candidates, while lacking stability in the environment of choice in these studies.Literature:[1] Y. Abghoui, A.L. Garden, J.G. Howalt, T. Vegge and E. Skúlason, Electroreduction of N2 to ammonia at ambient conditions on mononitrides of Zr, Nb, Cr, and V: A DFT guide for experiments. ACS Catalysis, 2016.6(2): p. 635.[2] Y. Abghoui, A.L. Garden, V.F. Hlynsson, S. Björgvinsdóttir, H. Ólafsdóttir and E.Skúlason, Enabling electrochemical reduction of nitrogen to ammonia at ambient conditions through rational catalyst design. Physical Chemistry Chemical Physics,2015.17(7): p. 4909.[3] F. Hanifpour, C.P. Canales, E.G. Fridriksson, A. Sveinbjörnsson, T.K. Tryggvason,E. Lewin, . H.D. Flosadóttir, Investigation into the mechanism of electrochemical nitrogen reduction reaction to ammonia using niobium oxynitride thin-film catalysts. Electrochimica Acta, 2022.403: p. 139551.[4] F. Hanifpour, C.P. Canales, E.G. Friðriksson, A. Sveinbjörnsson, T. Tryggvason, Y.Abghoui, . E. Skúlason, Operando Quanitification of ammonia produced from computationally derived transition metal nitride electro catalysts. Journal of Catalysis, 2022. 413: p.956

Gold Ultralow Loading on Nickel Foam for Nitrogen Electrochemical Reduction

Gold electroless deposition on nickel foam offers several advantages over traditional electrodeposition techniques. One of the main advantages is that it can produce uniform thickness coatings on complex shapes and geometries, such as porous and three-dimensional substrates like nickel foam. The resulting gold-nickel foam composite has high surface area and good electrical conductivity, making it suitable for various electrochemical applications, including catalysis, sensing, and energy storage.In this work we focused on the development of synthetic strategies to grow and optimize the surface coverage of gold on nickel foam and the evaluation of its suitability for the electrochemical reduction of nitrogen for ammonia synthesis.The gold electroless deposition on Ni Foam has been obtained by immersion in aqueous solution containing KAuCl4 and HCl, with or without stirring and addition of a surfactant agent (Isopropyl Alcohol). Depositions were performed by varying the immersion time from 30 seconds to 30 minutes. Scanning electron microscopy (SEM) has been employed to compare different deposition conditions and to optimize the morphology of the nanofilms, allowing higher catalytic activity. The electrochemical performance of the gold deposited on nickel foam was evaluated in a standard two compartments electrochemical cell using a Pt wire as counter electrode (CE), a saturated calomel electrode (SCE, saturated KCl) as reference and 0.1 M Na2SO4 solution as electrolyte. Electrochemical active surface area (EASA) and linear sweep voltammetry (LSV) have been adopted to evaluate the active area and the overpotential toward hydrogen evolution reaction (HER). Chronoamperometry experiments were carried out at various potentials to evaluate the performance of the catalyst for the electroreduction of nitrogen and ammonia synthesis.The amount of ammonia produced was measured by the indophenol blue method.The maximum NH3 yield of 2.8x10-11 mol s-1 cm-2 was achieved at -0.045 V vs RHE. The maximum faradaic efficiency of 5.8% was achieved at more positive potential (0.015 V vs RHE) due to the HER.The results show that the gold on nickel foam exhibits excellent electrochemical stability and high conductivity.This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under grant agreement No 101006941. This project started on the 1st of November 2020 with a duration of 42 months.

(Digital Presentation) In-Situ Spectroelectrochemistry to Unveil the Mechanism of Green Ammonia Production on the Ti2n Nitride Mxene

Electrochemical nitrogen reduction reaction (NRR) is used to convert nitrogen (N2) to ammonia (NH3) at ambient temperature and pressure. In general, acidic electrolytes are used to provide protons (H+) for the reduction process. However, this leads to a low NH3 selectivity because of H2 by-product formation via the hydrogen evolution reaction (HER). Recently, we showed that a Ti2N MXene is active and selective for NRR, and provided preliminary evidence that this catalyst works through a Mars-van Krevelen (MvK) mechanism rather than conventional associative/dissociative mechanisms. To improve the selectivity of the NRR process, the electrolyte was shifted from acidic to neutral pH values. From this, it was seen that NRR in 0.1M Na2SO4 was able to achieve a selectivity significantly greater than that of 0.1M HCl. We also observed that at more cathodic potentials, the material begins to irreversibly decompose into TiO2 as evidenced by cyclic voltammetry analysis before and after chronoamperometry experiments. To further understand the performance of this material, we use in-situ/operando techniques, including X-ray absorption spectroscopy (XAS) and Fourier-transform infrared (FTIR) spectroscopy, to deconvolute the mechanism of NH3 production. We use XAS to track the Ti oxidation state shift and degree of shift as a function of reaction time and applied potential. We also use XAS to track the change in the atomic bond lengths at the local coordination environment of the Ti atoms throughout time and voltage. Furthermore, we use FTIR to elucidate in real-time the adsorption of NRR reactive species and intermediates on the MXene surface. All findings are further corroborated with density functional theory (DFT) calculations to track the reaction energy pathway over each intermediate. We plan to expand these findings to other materials and systems, and use the knowledge obtained from these studies to design optimal electrolytic conditions to produce NH3 through NRR.

Is Ethanol Essential for the Lithium-Mediated Nitrogen Reduction Reaction?

Ammonia is used extensively as a fertilizer in agriculture and in the chemical industry. It also has the potential to store carbon-neutral fuel (hydrogen) in the future. To help meet the future demand for ammonia, the electrochemical nitrogen reduction reaction (NRR) has received much attention. It would serve as a decentralized method of synthesizing ammonia at low temperature and pressure. [1]To this day, the most promising NRR results have been shown via the lithium-mediated approach, in which lithium metal is electroplated in an organic electrolyte containing a lithium salt, saturated nitrogen gas, and a proton shuttle. The saturated nitrogen in the electrolyte reacts with electrodeposited lithium and protons are subsequently delivered by the shuttle. The local availabilities of protons and nitrogen are crucial for achieving a high selectivity towards ammonia rather than hydrogen evolution. The selectivity is heavily affected by the solid electrolyte interphase (SEI) which is formed between the electrodeposited lithium and bulk electrolyte. [2,3,4,5]This study investigates the role of ethanol as the proton shuttle in the lithium-mediated nitrogen reduction reaction (Li-NRR). In situ mass spectrometry and electrochemical quartz crystal microbalance are used to elucidate the importance of ethanol. Furthermore, particularly designed chronopotentiometry experiments are designed to provide additional information, allowing for a detailed discussion of ethanol’s multifaceted role in the Li-NRR. It is shown that ethanol is crucial for the formation of the SEI, but not necessary for the actual synthesis of ammonia. The SEI formation in the Li-NRR system is critically influenced by ethanol at the onset of lithium plating. Ethanol is not necessary to shuttle protons from the anode to the cathode. Furthermore, it is shown that lithium is an active species in the Li-NRR system even without electrochemistry. Finally, it is revealed that ethanol plays an important role in the context of anodic electrode potentials and electrolyte stability.References MacFarlane, D. R. et al. Adv. Mater. 32, 1904804 (2020)Du, H-L et al. Nature 609, 722 (2022)Lazaouski, N. et al. ACS Catal. 12, 5197-5208 (2022)Andersen, S. Z. et al. Energy Environ. Sci. 13, 4291-4300 (2020)Andersen, S. Z. et al. Nature 570, 504 (2019)

Electrochemical N2-to-NH3 with high faradaic efficiency on ZrO2/carbon quantum dots catalysts in neutral electrolyte

Electrochemical nitrogen reduction (NRR) to synthesize NH3 is limited by low Faraday efficiency (FE). Developing electrocatalysts that can efficiently adsorb/activate N2 and suppress hydrogen evolution reaction (HER) to enhance FE is needed. In this work, x-ZrO2/CQDs-T series catalysts were successfully prepared. The results demonstrate that: (I) The appropriate introduction of carbon quantum dots (CQDs) effectively enhances the surface adsorption capacity of ZrO2/CQDs for N2. (II) By high-temperature calcination eliminates the alkaline functional group (-NH2) of CQDs, which reduces the basicity of ZrO2/CQDs catalyst and inhibits the adsorption of protons on the catalyst surface. (III) Due to the semiconductor properties of ZrO2, the charge transfer efficiency of ZrO2/CQDs catalyst is significantly reduced, thereby weakening the binding of electrons to the adsorbed protons. As a result, 1-ZrO2/CQDs-750 catalyst appropriately and effectually restricts the accessibility of protons/electrons and promotes more N2 molecules to occupy active sites, thus achieving up to 66.62 % FE, which is superior to most reported NRR catalysts so far. Meanwhile, electrochemical in situ ATR-SEIRAS technique reveals that 1-ZrO2/CQDs-750 catalyst surface occurs in associative alternating reactions. The introduction of CQDs not only effectively affects the adsorption of N2 and N-related intermediates on ZrO2/CQDs catalyst and limits the proton/electron accessibility to improve FE of NRR, but also promotes the exposure of active sites to increase NH3 yield.

Design of Single-Atom Catalysts for E lectrocatalytic Nitrogen Fixation.

The Electrochemical nitrogen reduction reaction (ENRR) can be used to solve environmental problems as well as energy shortage. However, ENRR still faces the problems of low NH3 yield and low selectivity. The NH3 yield and selectivity in ENRR are affected by multiple factors such as electrolytic cells, electrolytes, and catalysts, etc. Among these catalysts are at the core of ENRR research. Single-atom catalysts (SACs) with intrinsic activity have become an emerging technology for numerous energy regeneration, including ENRR. In particular, regulating the microenvironment of SACs (hydrogen evolution reaction inhibition, carrier engineering, metal-carrier interaction, etc.) can break through the limitation of intrinsic activity of SACs. Therefore, this Review first introduces the basic principles of NRR and outlines the key factors affecting ENRR. Then a comprehensive summary is given of the progress of SACs (precious metals, non-precious metals, non-metallic) and diatomic catalysts (DACs) in ENRR. The impact of SACs microenvironmental regulation on ENRR is highlighted. Finally, further research directions for SACs in ENRR are discussed.

Tuning transition metal atoms embedded in N6 cavity structure toward efficient electrocatalytic ammonia synthesis

Electrochemical nitrogen reduction reaction (NRR) has become a promising route for ammonia synthesis. Designing a providential catalyst is a key strategy to further improve electrocatalytic activity. In this study, we systematically explored the NRR catalytic performance of transition metal (TM) atoms supported in graphitic C3N with six-fold N cavity (TM/TM2@C3N) through density functional theory (DFT) calculations. Our results show that, compared to single atom catalysts (SACs), homonuclear double atom catalysts (DACs) can produce a strong d-p orbital coupling to facilitate the activation and reduction of N2. Among these catalysts, the low limiting potentials are required for Mn2@C3N and Fe2@C3N (−0.33 V/−0.47 V) along distal path, which can also suppress the competitive hydrogen evolution reaction. Our results unveil that the Mn_d orbitals accepted electrons while the dzx/dyz orbitals donate them back to *N2, resulting in the bonding states and antibonding states. Meanwhile, the higher d-band center of Mn2 results in fewer electrons in the equivalent antibonding states, increasing the binding strength of Mn–N2. Fe2@C3N is the opposite in Mn2@C3N. Importantly, the limiting potential of NRR on TM2@C3N illustrates a volcanic relationship with the adsorption free energy of the reaction intermediate *NH2 (ΔG*NH2). And the ΔG*NH2 can be used as descriptor to make the activity trend clear. Our work provides a new perspective for measuring and screening high-efficiency DACs for NRR.

Exploring the source of ammonia generation in electrochemical nitrogen reduction using niobium nitride.

In this study, niobium nitride (NbN) is prepared via the urea-glass route by annealing a mixture of NbCl5 and urea at 650 °C under a flow of N2, and is used as a catalyst for the electrochemical nitrogen reduction reaction (NRR). The as-prepared NbN exhibits a maximum production rate of 5.46 × 10-10 mol s-1 cm-2 at -0.6 V vs. RHE, along with an apparent FE of 16.33% at -0.3 V vs. RHE. In addition, the leaching of NbN is confirmed by ICP-OES, where the leached amount of Nb is almost identical to the amount of N measured by UV-vis. Moreover, 1H NMR experiments are performed using 15N2 as the feeder gas; the dominant detection of 14NH4+ peaks strongly suggests that the produced NH3 originates from the leaching of NbN rather than via an electrocatalytic process. Hence, for a comprehensive understanding of NH3 generation, especially when utilizing transition metal nitride (TMN)-based NRR catalysts, a thorough investigation employing multiple analytical methods is imperative.

Molecular Imprinting Technology Enables Proactive Capture of Nitrogen for Boosted Ammonia Synthesis under Ambient Conditions.

Electrochemical nitrogen reduction reaction (NRR) is a burgeoning field for green and sustainable ammonia production, in which numerous potential catalysts emerge endlessly. However, satisfactory performances are still not realized under practical applications due to the limited solubility and sluggish diffusion of nitrogen at the interface. Herein, molecular imprinting technology is adopted to construct an adlayer with abundant nitrogen imprints on the electrocatalyst, which is capable of selectively recognizing and proactively aggregating high-concentrated nitrogen at the interface while hindering the access of overwhelming water simultaneously. With this favorable microenvironment, nitrogen can preferentially occupy the active surface, and the NRR equilibrium can be positively shifted to facilitate the reaction kinetics. Approximately threefold improvements in both ammonia production rate (185.7µg h-1 mg-1 ) and Faradaic efficiency (72.9%) are achieved by a metal-free catalyst compared with the bare one. It is believed that the molecular imprinting strategy should be a general method to find further applicability in numerous catalysts or even other reactions facing similar challenges.

Lithium-Mediated Ammonia Electrosynthesis with Ether-Based Electrolytes.

Ammonia is of great importance in fertilizer production and chemical synthesis. It can also potentially serve as a carbon-free energy carrier for a future hydrogen economy. Motivated by a worldwide effort to lower carbon emissions, ammonia synthesis by lithium-mediated electrochemical nitrogen reduction (LiNR) has been considered as a promising alternative to the Haber-Bosch process. A significant performance improvement in LiNR has been achieved in recent years by exploration of favorable lithium salt and proton donor for the electrolyte recipe, but the solvent study is still in its infancy. In this work, a systematic investigation on ether-based solvents toward LiNR is conducted. The assessments of solvent candidates are built on their conductivity, parasitic reactions, product distribution, and faradaic efficiency. Notably, dimethoxyethane gives the lowest potential loss among the investigated systems, while tetrahydrofuran achieves an outstanding faradaic efficiency of 58.5 ± 6.1% at an ambient pressure. We found that solvent molecules impact the above characteristics by dictating the solvation configurations of conductive ions and inducing the formation of solid electrolyte interphase with different compositions. This study highlights the importance of solvents in the LiNR process and advances the electrolyte optimization for better performance.

Regulating the electrocatalytic performance for nitrogen reduction reaction by tuning the N contents in Fe3@NxC20-x (x = 0~4): a DFT exploration

The Haber-Bosch (H-B) process, which is widely used in industry to synthesize ammonia, leads to serious energy and environment-related issues. The electrochemical nitrogen reduction reaction (eNRR) is the most promising candidate to replace H-B processes because it is more energy-efficient and environmentally friendly. Atomic-level catalysts, such as single-atom and double-atom catalysts (SACs and DACs), are of great interest due to their high atomic utilization and activity. The synergy between the metal atoms and two-dimensional (2D) support not only modulates the local electronic structure of the catalyst but also controls the catalytic performance. In this article, we explored the eNRR performance of 2D Fe3@Nx C20-x (x = 0~4), whose structure was based on the experimentally synthesized Ag3@C20 sheet, by means of density functional theory calculations. Through calculations, we found that the 2D Fe3@N4C16 with Fe2 site coordinated with four N is a promising eNRR catalyst: the limiting potential is as low as -0.45 V, and the competing hydrogen evolution reaction can be effectively suppressed. Our work not only confirms that the coordination environment of the metal site is crucial for the electrocatalytic activity but also provides a new guideline for designing low-cost eNRR catalysts with high efficiency.

Modulating the coordination environment of active site structure for enhanced electrochemical nitrogen reduction: The mechanistic insight and an effective descriptor

The effect of coordination environment of active site structure can never be underestimated in the rational design of a high-performance catalyst especially in electrochemical application. We designed a B-modified C2N-based double-atom catalyst (M2@B2-C2N) with the hybrid coordination of B2N4, on which electrochemical nitrogen reduction reaction (NRR) was computationally studied. Our DFT calculations revealed that the NRR could proceed highly efficiently for M2 = Mo2 and W2 with the onset potential of UL = -0.25 V and UL = -0.27 V, respectively. Remarkably, the NRR complied with a special quasi-dissociative mechanism instead of the conventional associative mechanism on M2@B2-C2N (M2 = Mo2 and W2). Using the optimal metal-based catalyst as a reference, these two model catalysts could yield superior NRR selectivity with respect to HER. The AIMD simulation demonstrated that the NRR could proceed with the applied potential of cathode as URHE = -0.20 V (Mo2) and −0.39 V (W2). The underlying chemical and structural origin of coordination environment was formulated as an effective descriptor Ω, which enables to bridge the NRR activity and active site structure. Our study could further the understanding of metal active site structure that catalyzes an electrochemical reaction involving small molecules.

Design of Electrocatalytic Janus WSeS/WSe2 Heterostructure Nanowall Electrodes with High Selectivity and Faradaic Efficiency for Nitrogen Reduction

AbstractThe electrochemical nitrogen reduction reaction (NRR) is an attractive process for next‐generation ammonia synthesis; therefore, identifying a suitable catalyst for this reaction is critical. In recent years, transition‐metal dichalcogenides (TMDs) and their Janus structures have gained significant attention because of their outstanding catalytic properties. However, the synthesis of Janus TMDs remains challenging, and exposing their active sites is difficult when using a low‐dimensional structure to improve the catalytic activity. To date, relatively little research has been conducted in this area. Herein, emerging Janus WSeS/WSe2 heterostructure nanowalls are systematically explored. These nanowalls are used as a nitrogen fixation catalyst in electrolytes. The nanowalls demonstrate a significant NH3 yield rate and Faradaic efficiency of 13.97 µg h‐mgcat−1 and 35.24% at −0.3 V in 0.1 m HCl, as well as 15.96 µg h‐mgcat−1 and 40.2% in 0.1 M Na2SO4. This study presents an in‐depth analysis of the properties of Janus WSeS/WSe2 heterostructure nanowalls and a conceptual framework for linking TMD‐based catalysts and the NRR.

Regulation of cerium species in Keggin structure of phosphotungstic acid for efficient nitrogen electroreduction to ammonia

As a sustainable and economical strategy, electrochemical nitrogen reduction reaction (eNRR) is a promising alternative of energy-intensive Haber-Bosch process to produce ammonia. Fabricating efficient catalysts for eNRR is still challenging due to the bottleneck of insufficient activity and low electron selectivity. Herein, phosphotungstic acid (PTA) as substrate to anchor cerium species on the 4-fold hollow site was prepared, which reaches high ammonia yield rates of 42 μg h−1 mgcat−1 and Faradaic efficiencies of 9.2 % at −0.6 V versus reversible hydrogen electrode. Experiments and theoretical calculations reveal that the introduction of Ce species could significantly improve the electronic density of adjacent exposed W atoms, further boosting the effective adsorption and activation of N2 to form active *N2. Finally, the designed Ce-PTA catalysts show high electrocatalytic activity of N2 reduction into ammonia. This work highlights the important role of using PTA as substrate to prepare stable supported metal species for heterogeneous electrocatalysis.

Transition-metal-based Catalysts for Electrochemical Synthesis of Ammonia by Nitrogen Reduction Reaction: Advancing the Green Ammonia Economy.

Ammonia (NH3), a cornerstone in the chemical industry, has historically been pivotal for producing various valuable products, notably fertilizers. Its significance is further underscored in the modern energy landscape, where NH3 is seen as a promising medium for hydrogen storage and transportation. However, the conventional Haber-Bosch process, which accounts for approximately 170 million ton of NH3 produced globally each year, is energy-intensive and environmentally damaging. The electrochemical nitrogen reduction reaction (NRR) emerges as a sustainable alternative that operates in ambient conditions and uses renewable energy sources. Despite its potential, the NRR faces challenges, including the inherent stability of nitrogen and its competition with the hydrogen evolution reaction. Transition metals, especially ruthenium (Ru) and molybdenum (Mo), have demonstrated promise as catalysts, enhancing the efficiency of the NRR. Ru excels in catalytic activity, while Mo offers robustness. Strategies like heteroatom doping are being pursued to mitigate NRR challenges, especially the competing hydrogen evolution reaction. This review delves into the advancements of Ru and Mo-based catalysts for electrochemical ammonia synthesis, elucidating the NRR mechanisms, and championing the transition towards a greener ammonia economy. It also seeks to elucidate the core principles underpinning the NRR mechanism. This shift aims not only to address challenges inherent to traditional production methods but also to align with the overarching goals of global sustainability.

Tuning Main Group Element-based Metal-Organic Framework to Boost Electrocatalytic Nitrogen Reduction Under Ambient Conditions.

Main group element-based materials are emerging catalysts for ammonia (NH3 ) production via a sustainable electrochemical nitrogen reduction reaction (N2 RR) pathway under ambient conditions. However, their N2 RR performances are less explored due to the limited active behavior and unclear mechanism. Here, an aluminum-based defective metal-organic framework (MOF), aluminum-fumarate (Al-Fum), is investigated. As a proof of concept, the pristine Al-Fum MOF is synthesized by the solvothermal reaction process, and the defect engineering method namely solvent-assisted linker exchange, is applied to create the defective Al sites. The defective Al sites play an important role in ensuring the N2 RR activity for defective Al-Fum. It is found that only the defective Al-Fum enables stable and effective electrochemical N2 RR, in terms of the highest production rate of 53.9µg(NH3 ) h-1 mgcat -1 (in 0.4m K2 SO4 ) and the Faradaic efficiency of 73.8% (in 0.1m K2 SO4 ) at -0.15V vs reversible hydrogen electrode) under ambient conditions. Density functional theory calculations confirm that the N2 activation can be achieved on the defective Al sites. Such sites also allow the subsequent protonation process via the alternating associative mechanism. This defect characteristic gives the main group Al-based MOFs the ability to serve as promising electrocatalysts for N2 RR and other attractive applications.