Ni Doping Research Articles

Spray pyrolysis grown Cu and Ni co-doped ZnO thin films: a study of their structural, optical, wettability, and photocatalytic performance

This study explores the impact of Cu and Ni doping on the structural, wettability, optical, and photocatalytic properties of ZnO thin films. The co-doped thin films, with varying Ni concentrations, were deposited using a spray pyrolysis method onto pre-heated soda lime glass substrates. X-ray diffraction analysis confirmed the hexagonal wurtzite structure with preferred orientation primarily along the (002) plane, while crystallinity decreased with higher Ni concentrations. Scanning electron microscopy reveals a compact, adherent structure in all films, with Ni incorporation altering the surface morphology. Fourier transform infrared spectroscopy identified characteristic absorption bands for metal-oxygen bonds. Optical analysis indicated that all thin films exhibited over 88% average transmittance in the visible region, accompanied by a red shift in the optical bandgap. Photoluminescence spectra exhibited a broad emission band in the visible region, indicating intrinsic and extrinsic defects induced by doping. Co-doping transforms the wettability character of ZnO thin films from hydrophilic to hydrophobic. Finally, the photodegradation efficiency of the thin films against methylene blue under sunlight significantly increases from 72% to 92% with an increase in Ni concentration.

Exploration of laser-assisted chemical bath for enhancing synthesis of undoped and nickel-doped zinc oxide and its potential applications in water purification and mitigating antimicrobial resistance

This study aims to explore the antimicrobial and photocatalytic efficiencies of pure and Ni-doped ZnO nanostructures produced via Laser-assisted Chemical Bath Synthesis (LACBS) to develop sustainable solutions for water treatment and pathogen control amid the global water crisis exacerbated by climate change and environmental pollution. Utilizing zinc acetate dihydrate and hexamethylenetetramine, the nanostructures were synthesized with Ni doping levels of 0.0 %, 1.5 %, 3.0 %, and 4.5 %, targeting their promising photocatalytic and antimicrobial properties to combat contaminants from pharmaceuticals, agriculture, and industries. Morphological analyses using Scanning Electron Microscopy showed a transition from hexagonal particles to nanoflowers, enhancing photocatalytic activity due to increased surface-to-volume ratio. X-ray Diffraction confirmed the hexagonal wurtzite structure, with variations in peak intensities indicating improved crystallinity with Ni doping. Energy Dispersive X-ray analysis verified the purity and successful incorporation of Ni. Photocatalytic assessments indicated up to 99.24 % degradation of Methylene Orange dye under blue laser irradiation within 60 minutes, correlating with Ni content. Antimicrobial tests demonstrated effective inhibition of pathogens such as Escherichia coli, Staphylococcus aureus, and additional strains like Candida albicans and Klebsiella pneumonia, with increasing zones of inhibition corresponding to higher Ni levels, extending up to 37 mm. The results underscore the dual functionality of ZnO nanostructures for applications in sustainable water treatment and antimicrobial controls, highlighting the need for future studies to examine the impacts of further increased doping concentrations on the material properties and efficacy.

High selectivity syngas generation by double perovskite oxygen carriers La2Fe2-xCoxO6 for chemical looping steam methane reforming

The generation of high-quality syngas combined with high-purity hydrogen is an essential challenge in the chemical looping steam methane reforming (CL-SMR) process, in which the design of oxygen carriers (OCs) is crucial. In this study, La2FeBO6 (BCr, Ni，Co) and La2Fe2-xCoxO6 (x = 0.2, 0.4, 0.6, 0.8, 1.0) double perovskites have been investigated as OCs in the CL-SMR process. Various analytical techniques (BET, XPS, XRD, H2-TPR, Raman.) have been deployed to characterize the OCs' specific surface area, crystal structure, and surface oxygen species. The fixed-bed experiments revealed that the Cr-modified perovskite had the lowest reactivity, which was attributed to the creation of LaCrO3 limiting the oxygen release rate of the OC. Meanwhile, Ni doping exhibited the maximum methane conversion (99.15 %), but it resulted in more carbon deposition due to methane cracking, and its carbon deposition was four times than that of Co doping. Whereas, the Co doped double perovskite OCs showed excellent overall performance, in which La2Fe1.8Co0.2O6 (L2F1.8Co0.2) exhibited the optimum CO selectivity (90.72 %), H2 selectivity (96.91 %), and H2 purity (96.84 %), as well as the lowest carbon deposition. Moreover, the L2F1.8Co0.2 also exhibited outstanding stability in 10 cycles, and it could be a prospective material for CL-SMR, enabling the simultaneous generation of high-quality syngas and high-purity hydrogen.

Engineering Nickel Dopants in Atomically Thin Molybdenum Disulfide for Highly Efficient Nitrate Reduction to Ammonia

AbstractThe electrocatalytic nitrate reduction reaction (NO3−RR) presents a promising pathway for achieving both ammonia (NH3) electrosynthesis and water pollutant removal simultaneously. Among various electrocatalysts explored, 2D materials have emerged as promising candidates due to their ability to regulate electronic states and active sites through doping. However, the impact of doping effects in 2D materials on the mechanism of NO3−RR remains relatively unexplored. Here, Ni‐doped MoS2 (Ni‐MoS2) nanosheets are investigated as a model system, demonstrating enhanced NO3−RR performance compared to undoped counterparts. By controlling the doping concentration, the Ni‐MoS2 nanosheets achieve a remarkable faradic efficiency (FE) of 92.3% for NH3 at −0.3 VRHE with excellent stability. The mechanistic studies reveal that the elevation of the NO3−RR performances originates from the generation of more active hydrogen and the acceleration of the reaction from nitrite (NO2−) to NH3 facilitated by Ni doping. Combining the experimental observations and theoretical calculations it is revealed that the appropriate Ni doping level in MoS2 can enhance *NO3 adsorption strength, thereby facilitating subsequent electrocatalytic steps. Together with the demonstration of Zn−NO3− and Zn−NO2− battery devices, the work provides new insights into the design and regulation of the active sites in 2D material catalysts for efficient NO3−RR.

Investigating the synergistic effect of Nd3+ and Ni2+ in CuO nanocrystals on their structural, optical, and magnetic properties for photovoltaic and photocatalytic implementations

The wet chemical precipitation technique was used to synthesize CuO, Nd:CuO and Ni-Nd:CuO nanoparticles efficiently. The produced substance was tested using X-ray diffraction (XRD) for confirming the crystallite structure, and scanning electron microscopy (SEM) was used to examine the morphological properties of the produced materials. Crystal defects and optical properties of the synthesized samples were analyzed through luminescence (PL) investigations and UV–Vis spectroscopy. EIS spectrum was utilized to study the electrochemical behavior of the prepared material. Vibrating Sample Magnetometer (VSM) was employed to examine the magnetic properties influencing from the doping of Ni2+ and Nd3+ ions into CuO, attributed to their substantial magnetic moment and ferromagnetic traits. Photovoltaic efficiency of the prepared material was studied by J-V characteristics and photon-to-electron converting efficacy (IPCE) studies. Photocatalytic properties were studied by degrading MB and RhB dyes. The enhancement in the photocatalytic performance of the Ni-Nd:CuO was a result of suppression of photogenerated electron-hole pair recombination and accelerated separation and migration of photogenerated charges.

Unveiling the Mn3+/ Mn4+ and Ni2+ potential as a high-capacity material for next-generation energy storage devices

In this study, we synthesized MnOx nanowires via hydrothermal methods and explored the impact of nickel (Ni) doping on their morphology and electrochemical properties. We investigated the structural and chemical changes induced by Ni incorporation by utilizing TEM and XPS analyses. Our results revealed that Ni doping influenced the distribution of manganese oxidation states, with 1.6 wt% Ni-doped nanowires exhibiting the optimized condition. Also, we observed a balance between the Mn3+/Mn4+ ratio with the Ni doping. Electrochemical characterization demonstrated enhanced capacity in Ni-MnOx nanowires at the 1.6 wt% Ni doping level. Galvanostatic charge-discharge measurements confirmed the superior performance of this level of Ni doping; moreover, the fabrication of asymmetric supercapacitor cells using these nanowires showed improved energy storage capabilities. The main results showed exceptionally high capacity (955.55 and 383.33 mAh g−1 at 1 and 20 A g−1, respectively) and an excellent rate capability. Cycling stability tests over 8500 cycles demonstrated excellent retention of capacity, underscoring the durability of the optimized Ni-MnOx nanowires, with a retention of 85 % of its initial capacity. Thus, this study emphasizes the significance of Ni doping in MnOx nanowires for enhancing electrochemical performance when the synthetic process is controlled, offering valuable insights for high-performance energy storage device development.

Effects of transition metals (V, Cr, Mn, Fe and Ni) doping on magnetic properties of Co-based amorphous alloys

Amorphous alloys exhibit numerous interesting and abundant magnetic properties due to their disordered structural traits and have been extensively studied by researchers. In this work, the effects of a small amount of transition metals doping on the magnetic properties of Co80-xMxB20 (x = 0, 2, 4, 6, 8, 10; M = V, Cr, Mn, Fe, Ni) amorphous alloys were systematically investigated by utilizing first-principles molecular dynamics. The trend of the magnetic moment change in the simulated calculation conforms well to the experimental results. The doping of V atoms leads to the fastest rate of decrease in the magnetic moment of the surrounding Co atoms, and there is only an antiferromagnetic interaction between the V and Co atoms. When doped with Cr and Mn atoms, there is mutual competition between ferromagnetic and antiferromagnetic coupling in the amorphous alloy, Cr reduces the magnetic moment of the surrounding Co atoms, while the change in the magnetic moment of the Co atoms around Mn is small. The doping of Fe and Ni causes an increase in the magnetic moment of the surrounding Co atoms. The reason may be due to the charge transfer between atoms. The doping of Fe and Ni has a small effect on the average magnetic moment of the Co atoms in the amorphous alloy. The results provide necessary theoretical support for the development of the Co-based amorphous alloys with excellent magnetic characteristics.

Exploring electrochemical kinetic behaviors and interfacial charge transfer of pure and Ni-doped ZnFe2O4 nanoparticles-based sensing nanoplatform for ultra-sensitive detection of chloramphenicol

ZnFe2O4 (ZFO) nanomaterial was doped with a divalent transition metal cation of Ni2+ (NixZn1-xFe2O4, x=0, 0.2, 0.4, and 0.8) and characterized by various analytical techniques. Powder X-ray diffraction revealed the formation of a single-phase cubic spinel structure, while the stabilization of crystal structure for Ni2+-doped samples was observed. The average crystalline size, d-spacing, and lattice parameters increased with increasing in Ni2+ concentration within NixZn1-xFe2O4, due to differences in the ionic radius, the cation distribution at A-B sites, and the creation of surface oxygen vacancies within ZFO structure. From electrochemical measurements, NixZn1-xFe2O4-based electrodes showed excellent enhancements in charge transfer ability and conductivity with the highest rate constant (0.018 ms−1), the lowest peak-to-peak separation (206 mV), the lowest Rct (118 Ω), and the largest electrochemical active area (0.248 cm2), compared to that of bare SPE. Among them, Ni0.8Zn0.2Fe2O4/SPE provided outstanding electrochemical behaviors and achieved the best sensing performance with the widened concentration linear range from 0.25 to 50 μM and a rather low detection limit of 0.2 μM for chloramphenicol detection. The most important reason for this positive advance comes from the unique synergistic effects of Ni doping into the ZFO host structure. The excellent enhancements in adsorption capacity (Г) (1.4 times higher), number of oxygen vacancies, charge transfer rate constant (approximately 1.15 times higher), and catalytic rate constant (30 times greater) were recorded at Ni-doped ZFO-based electrodes, compared to pure ZFO-based electrode. Furthermore, the detailed hypotheses and possible mechanisms explaining these impressive enhancements were explored. Our work provides insight into the correlation between the Ni-doping and electrochemical characteristics, which has implications for tailoring the electrochemical performance of spinel ferrites across diverse applications and the design of novel spinel ferrite nanomaterials.

The role of phase transformation (tetragonal – spinel) on the structural and mechanical properties of Ni doped CuFe2O4

Nano-ferrites of Cu1–xNixFe2O4 (x = 0 to 1 with step 0.2) system was synthesized utilizing the flash auto combustion process annealed at 600oC for 3 h. The structural characterization for synthesized samples was carried out using x-ray Diffraction (XRD), Fourier transition infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The hardness of the prepared material was measured using micro-indentation creep technology. XRD pattern verified the creation of a single-phase cubic spinel structure. The undesired CuO phase forms around \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:2\ heta\\:={50}^{^\\circ\\:}\\:$$\\end{document}for pure Copper ferrite and decreases with increasing Ni content. The average crystalline size decreases from 27.92 nm to 13.28 nm by doping process from x = 0.2 to x = 1 which retards the growth of crystalline size. FTIR spectra are distinguished by the presence of two prominent absorption bands, ν2 for the octahedral site and ν1 for the tetrahedral site, in the range of approximately 593 and 471 cm− 1, respectively. FTIR analysis verified the formation of the ferrite system’s spinel structure. The TEM images show a nanocrystalline nature with some agglomeration and the crystallites are spherical in shape which their sizes are agrees well with that obtained from XRD measurements. The hardness decreases as the dwell time increases. The hardness and yield strength (Y) values were significantly improved due to the decrease in the crystallite size after Ni doping. The stress exponent (n) value increases by increasing Ni content which means that the mechanical properties improved due to increment of resistance.

The synergistic effect of co-doping with Ti, Nb, and Ni on the hydrogen storage capacity of ZrCo

The effectiveness of element doping in enhancing the hydrogen storage performance of ZrCo alloys has been well established. However, the impact of single element doping is limited, and research on the synergistic effect of multi-element alloying remains relatively scarce. In this paper, the hydrogen storage properties of Zr0·75Ti0·125Nb0·125Co0·75Ni0.25 (ZTNCN) alloy were investigated using the first-principles method to explore the synergistic effect of Ti, Nb and Ni doping on ZrCo. The results indicate that the (−110) surface of ZTNCN undergoes significant reconstruction, leading to enhanced adsorption and dissociation of hydrogen on the surface. Moreover, there is no apparent dissociation barrier for H2, facilitating easier migration of H on the surface. The difference in atomic size leads to a variation in lattice interstices, resulting in a lower diffusion energy barrier for H compared to that of the ZrCoHx system. Through atomic substitution, the space within the 8e site becomes compressed, which makes the alloy exhibit improved resistance against disproportionation. Therefore, the synergistic effect of Ti, Nb, and Ni can greatly enhance hydrogen absorption and desorption kinetics in alloys and improve anti-disproportionation.

Atomic insight on the electronic structure and interfacial bonding characterization of the Cu/TiC interface

The interfacial bonding characteristics of ceramic reinforced phase and metal matrix in metal matrix composites have a significant impact on their strength. Herein, the interfacial bonding properties and alloy element doping of the Cu/TiC interface in TiC-reinforced Cu matrix composites with a stoichiometric ratio of TiC of 1:1 were investigated by atomistic DFT simulations. The analysis of twelve Cu/TiC interfacial models reveals that the TiC(111) in Cu/TiC interface with C-terminated is more stable than that of TiC(111) interface with Ti-terminated due to the stronger covalent bonds formed by Cu-C. The Cu(110)/TiC(111)-C interface with the highest work of adhesion (2.871 J/m2) is the most stable interface among these Cu/TiC interfaces. Moreover, the Cu-Co/TiC interface has the highest Wad (4.223 J/m2) compared to Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces. And the Cu-Zn/TiC interface has the lowest Wad (2.092 J/m2), which is even lower than that of the Cu/TiC interface (2.306 J/m2). During interfacial tension, the Cu/TiC, Cu-Ni/TiC, and Cu-Zn/TiC interfaces start to fracture either at the interface layer or the sub-interface layer on the Cu side, while the Cu-Co/TiC interface begins to fracture within the Cu slab. The Cu-Co/TiC interface has the highest tensile strength of 20.12 GPa at14 % strain compared to Cu/TiC (14.76 GPa), Cu-Ni/TiC (16.35 GPa), and Cu-Zn/TiC (15.30 GPa) interfaces, which is attributed to the strengthening of both the interface and sub-interface by Co doping. Thus, Co doping in the Cu matrix significantly strengthens the Cu/Ti interfacial bonding, Ni doping has a weaker strengthening effect, and zinc doping weakens the interfacial bonding.

The dual gain strategy of introducing nickel doping and anchoring amorphous iron oxyhydroxide nanosheets on ZIF-67 achieves an efficient oxygen evolution reaction

A ZIF-67@Ni@FeOOH composite material was synthesized using nickel-doped ZIF-67 as a precursor and was electrochemically characterized as an efficient oxygen evolution reaction (OER) catalyst. The results indicated that Ni doping preserved the polyhedral structure of ZIF-67 while enhancing its OER activity. The introduction of amorphous FeOOH nanosheets allowed ZIF-67@Ni@FeOOH to not only retain its original polyhedral structure but also develop a hollow interior and self-remodeling surface, resulting in numerous defects. These features contribute to improved charge transfer efficiency and enhanced conductivity of the material. The dual enhancement effect is achieved by combining the doping strategy with structural defect engineering. The synergistic effects of Co, Ni, and Fe species further boost OER performance. The ZIF-67@Ni@FeOOH catalyst exhibited remarkable OER efficacy, with the lowest overpotential at a current density of 10 mA cm−2 being 329 mV and a low Tafel slope of 42.95 mV dec−1. In situ Raman spectroscopy revealed that high-valence hydroxyl oxides, specifically NiOOH and CoOOH, present on the composite surface were the active species for OER. This study offers a promising approach for developing economically viable electrocatalysts with superior efficiency for OER.

Role of active redox sites and charge transport resistance at reaction potentials in spinel ferrites for improved oxygen evolution reaction

Fe and Ni oxide-based systems are often investigated as electrocatalysts for the oxygen evolution reaction (OER) in water electrolysis and the improvement in OER activity is explained by two main reasons, (i) improving bulk electrical conductivity and (ii) synergic effect between Ni and Fe. Among the two factors, the identification of the dominant factor for OER is very important for catalyst engineering in the right direction. In order to have a better understanding, spinel-structured ZnFe2O4 nanoparticles have been synthesized and its bulk conductivity is studied by progressively varying Ni doping. The conductivity of the synthesised compounds follows the order of ZnFe2O4 > Ni0.3Zn0.7Fe2O4 > Ni0.5Zn0.5Fe2O4 > Ni0.7Zn0.3Fe2O4 > NiFe2O4. The oxygen evolution studies reveal that NiFe2O4 is highly active with an onset potential of 1.57 V versus reversible hydrogen electrode (RHE) and Tafel slope of 102 mV/dec. With the increase in Ni doping, the structure changes from spinel to inverse spinel as confirmed by X-ray diffraction and Raman spectra. Further, the contribution from Ni redox sites in addition to Fe ion sites and FexNi1−xOOH species formation, causes improved OER performance. This study uniquely proves that the OER activity majorly relies on redox/active metal sites, FexNi1−xOOH species and charge transfer resistance at OER potential rather than the bulk electrical conductivity of spinel ferrites. This conclusion is supported by voltammetry and impedance studies of five different spinel ferrites.

Efficient recovery of lithium from shale gas wastewater: Fe, Ni, and Al doping of H1.33Mn1.67O4 for improved adsorption capacity and manganese loss reduction

To minimize manganese loss during acid leaching and to enhance the lithium adsorption capacity from shale gas wastewater of H1.33Mn1.67O4, this adsorbent material was doped with metallic elements in this study. Doping was achieved using solid-phase synthesis, resulting first in a Li1.33RXMn1.67−XO4 (R = Fe, Ni, Al) precursor powder through high-temperature calcination. Then, lithium was leached out under acidic environment to obtain the desired H1.33RXMn1.67−XO4 (HMO-R) adsorbents. The equilibrium adsorption capacities of HMO-R powders were measured as 20.7 mg/g, 20.7 mg/g, and 29.0 mg/g, for Fe, Ni, and Al dopants, respectively, surpassing that of the former H1.33Mn1.67O4 (13.7 mg/L). Moreover, an average reduction of manganese loss by 30% for HMO-R was observed during lithium recovery/extraction cycles by acid leaching compared to undoped Li1.33Mn1.67O4. Overall, the doped adsorbent exhibited a stable crystal structure and high adsorption capacity, enhanced stability, performance, and efficiency in cycling experiments with respect to the undoped material.

Ni-doped ZnO nanorods/Ti3C2 MXene composites and their photocatalytic performance

Herein, composites based on Ni-doped ZnO nanorods and Ti3C2 MXene structure (Ni-ZnO NR/Ti3C2) were produced via a simple hydrothermal method for photocatalytic applications. Special attention was paid to their structural and optical properties. The composite exhibited a photocatalytic effectiveness of 88.2% in degrading methyl orange (MO) within a duration of 75 minutes when exposed to a xenon lamp. The enhancement of the catalytic activity was due to the one-dimensional ZnO nanostructure, the Ni doping, and the Schottky heterojunction is formed by the interface within ZnO and Ti3C2. Therefore, this work provides an effective strategy to fabricate metal oxide/MXene photocatalysts.

Effect of Ni doping on the magnetic and photocatalytic properties of CoFe2O4 nanoparticles

Effect of Ni doping on the magnetic and photocatalytic properties of CoFe2O4 nanoparticles

Preparation and sodium storage properties of Ni-CoFe2O4/Reduced graphene oxide

The Ni-doped CoFe2O4 graphene composites (Ni-CFO/RGO) have been successfully prepared using the microwave-assisted method. The substance is a novel nanocomposite structure in which CoFe2O4 nanoparticles are tightly and uniformly attached to graphene hybrid nanosheets. The synergistic effect of Ni doping and CoFe2O4 can reduce the volume expansion of CoFe2O4 in the reaction process and inhibit the stacking of graphene. Because the Ni-CFO/RGO composite is structurally stable during the electrochemical reaction, it has a good theoretical capacity. Excellent carbon composite can further enhance the electron transport performance and structural stability of the material, thereby improving the electrochemical performance and cycle life of the material. Doping Ni2+ into metal oxides can not only form oxygen vacancies, and improve the transport capacity of sodium ions, but also broaden the electron transport channel. In addition, the catalyst can form a composite structure with metal oxide, which can effectively inhibit its volume expansion. At the same time, reacting with carbon materials, can also effectively reduce the accumulation of carbon, thereby reducing its resistance. After 200 cycles at a current density of 0.05 A g−1, it can provide a high sodium storage capacity of 380.6 mAh g−1, which still keeps 203.4 mAh g−1 at 1.5 A g−1.

Influence of Ni Doping on Oxygen Vacancy-Induced Changes in Structural and Chemical Properties of CeO2 Nanorods

In recent years, cerium dioxide (CeO2) has attracted considerable attention owing to its remarkable performance in various applications, including photocatalysis, fuel cells, and catalysis. This study explores the effect of nickel (Ni) doping on the structural, thermal, and chemical properties of CeO2 nanorods, particularly focusing on oxygen vacancy-related phenomena. Utilizing X-ray powder diffraction (XRD), alterations in crystal structure and peak shifts were observed, indicating successful Ni doping and the formation of Ni2O3 at higher doping levels, likely due to non-equilibrium reactions. Thermal gravimetric analysis (TGA) revealed changes in oxygen release mechanisms, with increasing Ni doping resulting in the release of lattice oxygen at lower temperatures. Raman spectroscopy corroborated these findings by identifying characteristic peaks associated with oxygen vacancies, facilitating the assessment of Ni doping levels. Ni-doped CeO2 can catalyze the ultrasonic degradation of methylene blue, which has good application prospects for catalytic ultrasonic degradation of organic pollutants. Overall, this study underscores the substantial impact of Ni doping on CeO2 nanorods, shedding light on tailored catalytic applications through the modulation of oxygen vacancies while preserving the nanorod morphology.

Ni doping in CZTS solar cells: a path to enhanced photovoltaic performance

Ni doping in CZTS solar cells: a path to enhanced photovoltaic performance

Promoting Electrochemical Nitrate Reduction to Ammonia on Silver Nanocrystals Doped with Iron Series Elements.

Electrochemical nitrate reduction to ammonia (NRA) is a promising approach to remove environmental pollutants while producing green NH3 under ambient conditions. Ag-based nanomaterials have been used in NRA but their iron series elements (Fe, Co, Ni) doping has not been explored yet. Herein, an effective and versatile doping strategy of Ag nanocrystals by iron series elements for efficient NRA is presented. Experimental results show that doping with Fe, Co or Ni can improve the NRA activity. Among the catalysts, AgCo delivers the best performance with a Faraday efficiency (FE) of 88.3 % and ammonia selectivity of 97.4 % at-0.23 V vs RHE, which is 1.9 and 6.2 times higher than that of plain Ag (46.4 % FE and 15.8 % selectivity), respectively. A highest NO3 - conversion rate of AgCo (91.8 %) is achieved, which maintains 16.4 ppm NO3 --N in 4 hours, meeting the drinking water level (~15 ppm NO3 --N). Moreover, the FE, selectivity, conversion rate of AgCo do not decay after the four consecutive cycles. It is found that Co doping can effectively induce the change of Ag d-band center for optimized NRA. This work reveals doping effects of iron series elements on Ag-based catalysts, and shows potential practical application in NRA.