Electrochemical Reduction Reaction Research Articles

In-situ construction of Ni–Fe alloy nanoparticles on perovskite surface for CO2 direct electrolysis

Perovskite (ABO3) materials are commonly used as cathodes for solid oxide electrolysis cells (SOECs), but their electrochemical performance is poor due to the low CO2 adsorption and conductivity. Herein, we design an A-site deficient (La0.5Sr0.5)0.95Fe0.85Mn0.1Ni0.05O3-δ (95LSFMNi) perovskite cathode with rich oxygen vacancy and Ni–Fe alloy to enhance the CO2 adsorption. The surface precipitated Ni–Fe alloy nanoparticles introduce more oxygen vacancies into the matrix and increase the active sites for CO2 adsorption, enhancing the electrochemical reduction reaction for CO2 (CO2RR). Fe element exsolution was stimulated after the Ni reduction, and Fe content in the nanoparticles increased with the reduced time. The 95LSFMNi with in-situ dissolved Ni–Fe particles exhibits a doubled conductivity than the parent La0.5Sr0.5Fe0.9Mn0.1O3-δ (LSFM) at 800 °C and 5%H2/Ar. In addition, the electrolysis current density at 1.6 V and 800 °C reaches 1.09 A cm−2, representing a 28.2% increase compared to the LSFM. These findings demonstrate that the in-situ precipitated nano Ni–Fe particles are highly effective in enhancing the catalytic ability of CO2RR.

Modulating Hydrogen Adsorption by Unconventional p-d Orbital Hybridization over Porous High-entropy Alloy Metallene for Efficient Electrosynthesis of Nylon-6 Precursor.

Renewable electricity driven electrosynthesis of cyclohexanone oxime (C6H11NO) from cyclohexanone (C6H10O) and nitrogen oxide (NOx) is a promising alternative to traditional environment-unfriendly industrial technologies for green synthesis of C6H11NO. Precisely controlling the reaction pathway of the C6H10O/NOx-involved electrochemical reductive coupling reaction is crucial for selectively producing C6H11NO, which is yet still challenging. Herein, we report a porous high-entropy alloy PdCuAgBiIn metallene (HEA-PdCuAgBiInene) to boost the electrosynthesis of C6H11NO from C6H10O and nitrite, achieving a high Faradaic efficiency (47.6%) and almost 100% yield under ambient conditions. In situ Fourier transform infrared spectroscopy and theoretical calculations demonstrate that unconventional orbital hybridization between d-block metals and p-block metals could regulate the local electronic structure of active sites and induce electron localization of electron-rich Pd sites, which tunes the active hydrogen supply and facilitates the generation and enrichment of key intermediates NH2OH* and C6H10O*, and efficiently promotes their C-N coupling to selectively produce C6H11NO.

Customizing pyridinic nitrogen coordination in Ni–N–C for electrocatalytic CO2 reduction towards CO

Nickel anchored N-doped carbon electrocatalysts (Ni–N–C) are rapidly developed for the electrochemical reduction reaction of carbon dioxide (CO2RR). However, the high-performanced Ni–N–C analogues design for CO2RR remains bewilderment, for the reason lacking of definite guidance for its structure-activity relationship. Herein, the correlation between the proportion of nitrogen species derived from various nitrogen sources and the CO2RR activity of Ni–N–C is investigated. The x-ray photoelectron spectroscopy (XPS) spectrum combined with the CO2RR performance results show that pyridinic-N content has a positive correlation with CO2RR activity. Moreover, density functional theory (DFT) demonstrates that pyridinic-N coordinated Ni–N4 sites offers optimized free energy and favorable selectivity towards CO2RR compared with pyrrolic-N. Accordingly, Ni–Na–C with highest pyridinic-N content (ammonia as nitrogen source) performs superior CO2RR activity, with the maximum carbon monoxide faradaic efficiency (FECO) of 99.8% at −0.88 V vs. RHE and the FECO surpassing 95% within potential ranging of −0.88 to −1.38 V vs. RHE. The building of this parameter for CO2RR activity of Ni–N–C give instructive forecast for low-cost and highly active CO2RR electrocatalysts.

Highly Selective Electrocatalytic CO2 Conversion to Tailored Products through Precise Regulation of Hydrogenation and C-C Coupling.

The electrochemical reduction reaction of carbon dioxide (CO2RR) into valuable products offers notable economic benefits and contributes to environmental sustainability. However, precisely controlling the reaction pathways and selectively converting key intermediates pose considerable challenges. In this study, our theoretical calculations reveal that the active sites with different states of copper atoms (1-3-5-7-9) play a pivotal role in the adsorption behavior of the *CHO critical intermediate. This behavior dictates the subsequent hydrogenation and coupling steps, ultimately influencing the formation of the desired products. Consequently, we designed two model electrocatalysts comprising Cu single atoms and particles supported on CeO2. This design enables controlled *CHO intermediate transformation through either hydrogenation with *H or coupling with *CO, leading to a highly selective CO2RR. Notably, our selective control strategy tunes the Faradaic efficiency from 61.1% for ethylene (C2H4) to 61.2% for methane (CH4). Additionally, the catalyst demonstrated a high current density and remarkable stability, exceeding 500 h of operation. This work not only provides efficient catalysts for selective CO2RR but also offers valuable insights into tailoring surface chemistry and designing catalysts for precise control over catalytic processes to achieve targeted product generation in CO2RR technology.

Insight into Fluoride Additives to Enhance Ammonia Production from Lithium-Mediated Electrochemical Nitrogen Reduction Reaction.

Demands for green ammonia production increase due to its application as a proton carrier, and recent achievements in electrochemical Li-mediated nitrogen reduction reactions (Li-NRRs) show promising reliability. Here, it is demonstrated that F-containing additives in the electrolyte improve ammonia production by modulating the solid electrolyte interphase (SEI). It is suggested that the anionic additives with low lowest unoccupied molecular orbital levels enhance efficiency by contributing to the formation of a conductive SEI incorporated with LiF. Specifically, as little as 0.3wt.% of BF4 - additive to the electrolyte, the Faradaic efficiency (FE) for ammonia production is enhanced by over 15% compared to an additive-free electrolyte, achieving a high yield of 161 ± 3nmol s-1 cm-2. The BF4 - additive exhibits advantages, with decreased overpotential and improved FE, compared to its use as the bulk electrolyte. The observation of the Li3N upper layer implies that active Li-NRR catalytic cycles are occurring on the outermost SEI, and density functional theory simulations propose that an SEI incorporated with LiF facilitates energy profiles for the protonation by adjusting the binding energies of the intermediates compared to bare copper. This study unlocks the potential of additives and offers insights into the SEIs for efficient Li-NRRs.

Interface Engineering of the Cu1.5Mn1.5O4/CeO2 Heterostructure for Highly Efficient Electrocatalytic Nitrate Reduction to Ammonia.

The electrochemical nitrate reduction reaction (NO3RR) is considered a sustainable technology to convert the nitrate pollutants to ammonia. However, developing highly efficient electrocatalysts is necessary and challenging given the slow kinetics of the NO3RR with an eight-electron transfer process. Here, a Cu1.5Mn1.5O4 (CMO)/CeO2 heterostructure with rich interfaces is designed and fabricated through an electrospinning and postprocessing technique. Benefiting from the strong coupling between CMO and CeO2, the optimized CMO/CeO2-2 catalyst presents excellent NO3RR performance, with NH3 Faraday efficiency (FE) up to 93.07 ± 1.45% at -0.481 V vs reversible hydrogen electrode (RHE) and NH3 yield rate up to 48.06 ± 1.32 mg cm-2 h-1 at -0.681 V vs RHE. Theoretical calculations demonstrate that the integration of CeO2 with CMO modulates the adsorption/desorption process of the reactants and intermediates, showing a reduced energy barrier in the rate determination step of NO* to N* and achieving an outstanding NO3RR performance.

An Anti-Scaling Strategy for Electrochemical Wastewater Treatment: Leveraging Tip-Enhanced Electric Fields.

Electrode scaling poses a critical barrier to the adoption of electrochemical processes in wastewater treatment, primarily due to electrode inactivation and increased internal reactor resistance. We introduce an antiscaling strategy using tip-enhanced electric fields to redirect scale-forming compounds (e.g., Mg(OH)2 and CaCO3) from the electrode-electrolyte interface to the bulk solution. Our study utilized Cu nanowires (Cu NW) with high-curvature nanostructures as the cathode, in contrast to Cu nanoparticles (Cu NP), Cu foil (CF), and Cu mesh (CM), to evaluate the electrochemical nitrate reduction reaction (NO3RR) performance in hard water conditions. The Cu NW/CF cathode demonstrated superior NO3RR efficiency, with an apparent rate constant (Kapp) of 1.04 h-1, significantly outperforming control electrodes under identical conditions (Kapp < 0.051 h-1). Through experimental and theoretical analysis, including COMSOL simulations, we show that the high-curvature design of Cu NW induced localized electric field enhancements, propelling OH- ions away from the electrode surface into the bulk solution, thus mitigating scale formation on the cathode. Testing with real nitrate-contaminated wastewater confirms that the Cu NW/CF cathode maintained excellent denitrification efficiency over a 60-day period. This study offers a promising perspective on preventing electrode scaling in electrochemical wastewater treatment, paving the way for more efficient and sustainable practices.

Manipulating d-band center of bimetallic Sn-alloy coupling with carbon nanofibers for high-performance electrocatalytic production of ammonia from nitrate

The production of ammonia from electrochemical nitrate reduction reaction (NO3RR) has emerged as a highly promising approach to replace the conventional “Haber-Bosch” process, but the research progress of this field is still hindered by the absence of a structure–activity relationship for manipulating catalyst structure to promote its catalytic performance. In this study, we chose TMSn (M=Fe, Co, Ni) alloys as the models to evaluate the electronic structure and their NO3RR activity. Alloying various transition metals with Sn allows to regulate charge distribution, thereby modulating the d-band center of the catalysts and further regulating the catalytic activity of NO3RR. Density functional theory (DFT) simulation predicts that CoSn alloy, with the strongest NO3− adsorption and lowest thermodynamic energy barrier, is potentially considered as a highly efficient NO3RR catalyst. With this theoretical guidance, a series of TMSn alloy catalysts with carbon nanofiber (TMSn-CNF) as a support were synthesized via a two-step electrospinning/carbonization strategy. The CNF as a substrate ensures the excellent cycling performance. As a result, a significantly enhanced NO3RR activity with a NH3 yield rate of 42.20 mg h−1 cm−2 at −0.6 V vs. RHE is achieved on CoSn-CNF compared with NiSn-CNF (13.91 mg h−1 cm−2), FeSn-CNF (13.81 mg h−1 cm−2) and Sn-CNF (6.10 mg h−1 cm−2), superior to most of the previously reported catalysts. We have further constructed an aqueous Zn-NO3− battery using CoSn-CNF as the cathode, achieving a remarkable power density of 5.88 mW cm−2. This battery not only generates large quantity of NH3, but also functions as an effective power source.

Nanoporous copper titanium tin (np-Cu2TiSn) Heusler alloy prepared by dealloying-induced phase transformation for electrocatalytic nitrate reduction to ammonia

Heusler alloys are a series of well-established intermetallic compounds with abundant structure and elemental substitutions, which are considered as potentially valuable catalysts for integrating multiple reactions owing to the features of ordered atomic arrangement and optimized electronic structure. Herein, a nanoporous copper titanium tin (np-Cu2TiSn) Heusler alloy is successfully prepared by the (electro)chemical dealloying transformation method, which exhibits high nitrate (NO3–) reduction performance with an NH3 Faradaic efficiency of 77.14 %, an NH3 yield rate of 11.90 mg h−1 mg−1cat, and a stability for 100 h under neutral condition. Significantly, we also convert NO3− to high-purity ammonium phosphomolybdate with NH4+ collection efficiency of 83.8 %, which suggests a practical approach to convert wastewater nitrate into value-added ammonia products. Experiments and theoretical calculations reveal that the electronic structure of Cu sites is modulated by the ligand effect of surrounding Ti and Sn atoms, which can simultaneously enhance the activation of NO3−, facilitate the desorption of NH3, and reduce the energy barriers, thereby boosting the electrochemical nitrate reduction reaction.

Machine-learning-aided Au-based single-atom alloy catalysts discovery for electrochemical NO reduction reaction to NH3

Machine-learning-aided Au-based single-atom alloy catalysts discovery for electrochemical NO reduction reaction to NH3

Highly Stable Perovskite Oxides for Electrocatalytic Acidic NOx− Reduction Streamlining Ammonia Synthesis from Air

Electrochemical nitrogen oxide ions reduction reaction (NOx−RR) shows great opportunity for ammonia production under ambient conditions. Yet, performing NOx−RR in strong acidic conditions remains challenging due to the corrosion effect on the catalyst and competing hydrogen evolution reactions. Here, we demonstrate a stable La1.5Sr0.5Ni0.5Fe0.5O4 perovskite oxide for the NOx−RR at pH 0, achieving a Faradaic efficiency for ammonia of approaching 100% at a current density of 2 A cm−2 in a H‐type cell. At industrially relevant current density, the NOx−RR system shows stable cell voltage and Faradaic efficiency for &gt;350 h in membrane electrode assembly (MEA) at pH 0. By integrating the catalyst in a stacked MEA with a series connection, we have successfully obtained a record‐breaking 2.578 g h−1 NH3 production rate at 20 A. This catalyst's unique acid‐operability streamlines downstream ammonia utilization for direct ammonium salt production and upstream integration with NOx sources. Techno‐economic and lifecycle assessments reveal substantial economic advantages for this ammonia production strategy, even when coupled with a plasma‐based NOx production system, presenting a sustainable complement to the conventional Haber‐Bosch process.

Reconstructing Solvation Structure by Steric Hindrance-Coordination Push-Pull of Dipolymer-H2O-Zn2+ toward Long-life Aqueous Zinc-Metal Batteries.

Aqueous zinc-metal batteries are prospective energy storge devices due to their intrinsically high safety and cost effectiveness. Yet, uneven deposition of zinc ions in electrochemical reduction and side reactions at the anode interface significantly hinder their development and application. Here, we propose a solvation-interface attenuation strategy enabled by a frustrated tertiary amine amphiphilic dipolymer electrolyte additive. The configuration of superhydrophilic segments with covalently bonded lipophilic spacers enables coupled steric hindrance/coordination, which establishes a balanced push-pull dynamic of dipolymer-H2O-Zn2+. Such interplay reconstructs the solvation structure of Zn2+ and allows the formation of a stable dipolymer-inorganic hybrid solid electrolyte interface (SEI) layer. This SEI layer effectively shields the zinc-metal anode from water and anions, significantly reducing side reactions. In addition, the dipolymer adsorbed at the zinc-metal anode interface regulates the interfacial electrochemical reduction kinetics and ensures uniform zinc deposition. As a result, the Zn-Zn symmetric cells with dipolymer-containing electrolyte exhibit remarkable cycling stability exceeding 5800 h (242 days). The Zn-NVO batteries and Zn-AC hybrid ion supercapacitors also deliver stable cycling for up to 1440 h (60 days) with high-capacity retention over 80%. This research demonstrates the potential to facilitate the development and commercialization of zinc-based energy storage devices.

Interfacial Accumulation and Stability Enhancement Effects Triggered by Built-in Electric Field of SnO2/LaOCl Nanofibers Boost Carbon Dioxide Electroreduction.

Constructing a built-in interfacial electric field (BIEF) is an effective approach to enhance the electrocatalysts performance, but it has been rarely demonstrated for electrochemical carbon dioxide reduction reaction (CO2RR) to date. Herein, for the first time, SnO2/LaOCl nanofibers (NFs) with BIEF is created by electrospinning, exhibiting a high Faradaic efficiency (FE) of 100% C1 product (CO and HCOOH) at -0.9--1.1V versus reversible hydrogen electrode (RHE) and a maximum FEHCOOH of 90.1% at -1.2 VRHE in H-cell, superior to the commercial SnO2 nanoparticles (NPs) and LaOCl NFs. SnO2/LaOCl NFs also exhibit outstanding stability, maintaining negligible activity degradation even after 10h of electrolysis. Moreover, their current density and FEHCOOH are almost 400mAcm-2 at -2.31V and 83.4% in flow-cell. The satisfactory CO2RR performance of SnO2/LaOCl NFs with BIEF can be ascribed to tight interface of coupling SnO2 NPs and LaOCl NFs, which can induce charge redistribution, rich active sites, enhanced CO2 adsorption, as well as optimized Gibbs free energy of *OCHO. The work reveals that the BIEF will trigger interfacial accumulation and stability enhancement effects in promoting CO2RR activity and stability of SnO2-based materials, providing a novel approach to develop stable and efficient CO2RR electrocatalysts.

An Energy-Efficient Integrated System by Coupling Carbon Dioxide Reduction and Methanol Oxidation to Produce the Identical Value-Added Formic Acid

Metal-organic frameworks (MOFs) are considered as promising catalytic materials for electrochemical carbon dioxide reduction (ECR) reactions due to their excellent properties. However, the development of efficient and stable electrocatalysts within a wide potential window remains a great challenge. Herein, the rod-like Sn-MOF is synthesized by a fast and simple solution reaction, which has good performance in converting CO2 to HCOOH. In particular, Sn-MOF reaches a maximum Faradaic efficiency of 86.4% at −1.15 V vs RHE with a current density of 25.2 mA cm−2. It is worth noting that Sn-MOF has excellent long-term stability, maintaining more than 80% of FEHCOOH production within 30 h of continuous electrolysis. Meanwhile, X-ray diffraction and X-ray photoelectron spectroscopy characterization confirm that Sn2+ in Sn-MOF can be reduced to Sn0 in the ECR reaction. The theoretical results show that *COOH intermediate tends to form in the ECR process on Sn-MOF, and it has a high selectivity for the formation of HCOOH. In addition, the two-electrode system driving the co-electrolysis of methanol and CO2 can significantly reduce the voltage by 500 mV at a current density of 20 mA cm−2.

Transformation of Bi4Cl2S5 into sub-10 nm Bi2O2CO3 nanowires for electrochemical reduction of CO2

The development of highly efficient catalysts for the selective electrochemical reduction reaction of CO2 (eCO2RR) to high-valued formate remains a challenge in achieving carbon neutrality and renewable energy conversion. In this study, ultrathin Bi4Cl2S5 nanowires, synthesized using different branched-chain thiols as sulfur sources, were reported for the first time as precatalysts for eCO2RR to formate. Systematic material characterization demonstrated that Bi4Cl2S5 can undergo in-situ evolution into Bi2O2CO3 nanowires, serving as the genuine electrocatalyst for eCO2RR. Through the fine-tuning of ligands during the synthesis of Bi4Cl2S5 nanowires, the optimized Bi4Cl2S5-derived Bi2O2CO3 nanowires exhibited a maximum formate Faradaic efficiency (FEformate) of 95.3 % in eCO2RR using a traditional H-cell, surpassing other prepared samples. Furthermore, an FEformate of over 92.9 % was achieved in a wide potential window of 500 mV, and high performance was maintained over 20 h. This outstanding performance is attributed to the high intrinsic activity, accelerated charge transfer, and the large electrochemical active surface area associated with the characteristic sub-10 nm diameter nanowire structure. Moreover, density function theory calculations further revealed that Bi2O2CO3 can reduce the energy barriers for the formation of *OCHO intermediate and bolster formate production. Our work provides a novel synthesis strategy for excellent Bi-based catalysts in electrocatalysis.

Modulating the Electrolyte Microenvironment in Electrical Double Layer for Boosting Electrocatalytic Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction reaction (NO3RR) is a promising approach to achieve remediation of nitrate-polluted wastewater and sustainable production of ammonia. However, it is still restricted by the low activity, selectivity and Faraday efficiency for ammonia synthesis. Herein, we propose an effective strategy to modulate the electrolyte microenvironment in electrical double layer (EDL) by mediating alkali metal cations in the electrolyte to enhance the NO3RR performance. Taking bulk Cu as a model catalyst, the experimental study reveals that the NO3--to-NH3 performance in different electrolytes follows the trend Li+ < Cs+ < Na+ < K+. Theoretical studies illustrate that the proton transport rate in NO3RR and the activity of the rate-determining step (NO3- to NO2-) increase in the order Li+ < Cs+ < Na+ < K+. The cation effects are also general for two typical nanostructured catalysts including copper/cuprous oxide and nickel phosphides, achieving near-100% Faradaic efficiency and over 99% conversion of NO3- to NH3. Furthermore, we demonstrate that NO3- can be converted to high-purity NH4Cl by copper/cuprous oxide catalyst in K+-containing electrolyte.

Modulating the Electrolyte Microenvironment in Electrical Double Layer for Boosting Electrocatalytic Nitrate Reduction to Ammonia

Electrochemical nitrate reduction reaction (NO3RR) is a promising approach to achieve remediation of nitrate‐polluted wastewater and sustainable production of ammonia. However, it is still restricted by the low activity, selectivity and Faraday efficiency for ammonia synthesis. Herein, we propose an effective strategy to modulate the electrolyte microenvironment in electrical double layer (EDL) by mediating alkali metal cations in the electrolyte to enhance the NO3RR performance. Taking bulk Cu as a model catalyst, the experimental study reveals that the NO3−‐to‐NH3 performance in different electrolytes follows the trend Li+ &lt; Cs+ &lt; Na+ &lt; K+. Theoretical studies illustrate that the proton transport rate in NO3RR and the activity of the rate‐determining step (NO3− to NO2−) increase in the order Li+ &lt; Cs+ &lt; Na+ &lt; K+. The cation effects are also general for two typical nanostructured catalysts including copper/cuprous oxide and nickel phosphides, achieving near‐100% Faradaic efficiency and over 99% conversion of NO3− to NH3. Furthermore, we demonstrate that NO3− can be converted to high‐purity NH4Cl by copper/cuprous oxide catalyst in K+‐containing electrolyte.

Mixed Fe-Mo carbide prepared by a sonochemical synthesis as highly efficient nitrate reduction electrocatalyst

Ammonia, a versatile compound that can be used as a fertilizer, chemical or fuel, has since long been produced through the energy-intensive Haber-Bosch process. Recently, the electrochemical nitrate reduction reaction (NO3RR) using electricity generated from renewable sources has attracted widespread attention. However, the complex reaction pathway of NO3RR leads to the formation of many undesirable by-products. Herein we successfully prepared a mixed (FeMo)2C catalyst with good electrocatalytic NO3RR, having a NH3 yield of 14.66 mg h-1 cm-2 and an FE of 94.35% at low potential -0.3 V vs RHE. DFT calculations show that the presence of Fe in Mo2C lattice changes the reaction mechanism, decreasing the potential barrier to be overcome from 1.36 to 0.89 eV. In addition, mixed Fe-Mo carbide facilitates the adsorption of intermediates and promotes NH3 desorption, facilitating NO3− reduction to NH3. In addition, (FeMo)2C was used as cathode for Zn-NO3 battery to generate electricity, producing ammonia at the same time, with a power density of 3.8 mWcm-2 and an NH3 FE of 88%. This work describes a new synthesis method for mixed metal carbides and provides a promising strategy for NH3 production.

Cu1‐Fe Dual Sites for Superior Neutral Ammonia Electrosynthesis from Nitrate

The electrochemical nitrate reduction reaction (NO3RR) is able to convert nitrate (NO3‐) into reusable ammonia (NH3), offering a green treatment and resource utilization strategy of nitrate wastewater and ammonia synthesis. The conversion of NO3‐ to NH3 undergoes water dissociation to generate active hydrogen atoms and nitrogen‐containing intermediates hydrogenation tandemly. The two relay processes compete for the same active sites, especially under pH‐neutral condition, resulting in the suboptimal efficiency and selectivity in the electrosynthesis of NH3 from NO3‐. Herein, we constructed a Cu1‐Fe dual‐site catalyst by anchoring Cu single atoms on amorphous iron oxide shell of nanoscale zero‐valent iron (nZVI) for the electrochemical NO3RR, achieving an impressive NO3‐ removal efficiency of 94.8% and NH3 selectivity of 99.2% under neutral pH and nitrate concentration of 50 mg L‐1 NO3‐‐N conditions, greatly surpassing the performance of nZVI counterpart. This superior performance can be attributed to the synergistic effect of enhanced NO3‐ adsorption on Fe sites and strengthened water activation on single‐atom Cu sites, decreasing the energy barrier for the rate‐determining step of *NO‐to‐*NOH. This work develops a novel strategy of fabricating dual‐site catalysts to enhance the electrosynthesis of NH3 from NO3‐, and presents an environmentally sustainable approach for neutral nitrate wastewater treatment.

Cu1-Fe Dual Sites for Superior Neutral Ammonia Electrosynthesis from Nitrate.

The electrochemical nitrate reduction reaction (NO3RR) is able to convert nitrate (NO3-) into reusable ammonia (NH3), offering a green treatment and resource utilization strategy of nitrate wastewater and ammonia synthesis. The conversion of NO3- to NH3 undergoes water dissociation to generate active hydrogen atoms and nitrogen-containing intermediates hydrogenation tandemly. The two relay processes compete for the same active sites, especially under pH-neutral condition, resulting in the suboptimal efficiency and selectivity in the electrosynthesis of NH3 from NO3-. Herein, we constructed a Cu1-Fe dual-site catalyst by anchoring Cu single atoms on amorphous iron oxide shell of nanoscale zero-valent iron (nZVI) for the electrochemical NO3RR, achieving an impressive NO3- removal efficiency of 94.8% and NH3 selectivity of 99.2% under neutral pH and nitrate concentration of 50 mg L-1 NO3--N conditions, greatly surpassing the performance of nZVI counterpart. This superior performance can be attributed to the synergistic effect of enhanced NO3- adsorption on Fe sites and strengthened water activation on single-atom Cu sites, decreasing the energy barrier for the rate-determining step of *NO-to-*NOH. This work develops a novel strategy of fabricating dual-site catalysts to enhance the electrosynthesis of NH3 from NO3-, and presents an environmentally sustainable approach for neutral nitrate wastewater treatment.