Advancements in Catalysts for Electrochemical Nitrate Reduction: A Sustainable Approach for Mitigating Nitrate Pollution: A Review

Nitrate pollution is of great importance in both the environmental and health contexts, necessitating the development of efficient mitigation strategies. This review provides a comprehensive analysis of the many catalysts employed in the electrochemical reduction of nitrate to ammonia, and presents a viable environmentally friendly approach to address the issue of nitrate pollution. Hence, the electrochemical transformation of nitrate to ammonia serves the dual purpose of addressing nitrate pollution in water bodies, and is a useful agricultural resource. This review examines a range of catalyst materials such as noble and non-noble metals, metal oxides, carbon-based materials, nitrogen-doped carbon species, metal complexes, and semiconductor photocatalysts. It evaluates catalytic efficiency, selectivity, stability, and overall process optimization. The performance of catalysts is influenced by various factors, including reaction conditions, catalyst structure, loading techniques, and electrode interfaces. Comparative analysis was performed to evaluate the catalytic activity, selectivity, Faradaic efficiency, current density, stability, and durability of the catalysts. This assessment offers significant perspectives on the structural, compositional, and electrochemical characteristics that affect the efficacy of these catalysts, thus informing future investigations and advancements in this domain. In addition to mitigating nitrate pollution, the electrochemical reduction of nitrate to ammonia is in line with sustainable agricultural methods, resource conservation, and the utilization of renewable energy resources. This study explores the factors that affect the catalytic efficiency, provides new opportunities to address nitrate pollution, and promotes the development of sustainable environmental solutions.

Preferentially selective extraction of lithium from spent LiCoO_(2)cathodes by medium-temperature carbon reduction roasting

Lithium recovery from spent lithium-ion batteries(LIBs)have attracted extensive attention due to the skyrocketing price of lithium.The medium-temperature carbon reduction roasting was proposed to preferential selective extraction of lithium from spent Li-CoO_(2)(LCO)cathodes to overcome the incomplete recovery and loss of lithium during the recycling process.The LCO layered structure was destroyed and lithium was completely converted into water-soluble Li2CO_(3)under a suitable temperature to control the reduced state of the cobalt oxide.The Co metal agglomerates generated during medium-temperature carbon reduction roasting were broken by wet grinding and ultrasonic crushing to release the entrained lithium.The results showed that 99.10%of the whole lithium could be recovered as Li2CO_(3)with a purity of 99.55%.This work provided a new perspective on the preferentially selective extraction of lithium from spent lithium batteries.

Intrinsic pentagon defect engineering in multiple spatial-scale carbon frameworks for efficient triiodide reduction

Intrinsic topological defect engineering has been proven as a promising strategy to elevate the electrocatalytic activity of carbon materials.However,the controllable construction of high-density and specific topological defects in carbon frameworks to reveal the relationship between reactivity and defect structure remains a challenging task.Herein,the intrinsic pentagon carbon sites that can favor electron overflow and enhance their binding affinity towards the intermediates of catalytic reaction are firstly presented by the work function and the p-band center calculations.To experimentally verify this,the cage-opening reaction of fullerene is proposed and utilized for synthesizing carbon quantum dots with specific pentagon configuration(CQDs-P),subsequently utilizing CQDs-P to modulate the micro-scale defect density of three-dimensional reduced graphene oxide(rGO)viaπ-πinteractions.The multiple spatial-scale rGO-conjugated CQDs-P structure simultaneously possesses abundant pentagon and edge defects as catalytic active sites and long-range-orderedπelectron delocalization system as conductive network.The defects-rich CQDs-P/rGO-4 all-carbon-based catalyst exhibits superb catalytic activity for triiodide reduction reaction with a high photoelectric conversion efficiency of 8.40%,superior to the Pt reference(7.97%).Theoretical calculations suggest that pentagon defects in the carbon frameworks can promote charge transfer and modulate the adsorption/dissociation behavior of the reaction intermediates,thus enhancing the electrocatalytic activity of the catalyst.This work confirms the role of intrinsic pentagon defects in catalytic reactions and provides a new insight into the synthesis of defects-rich carbon catalysts.

Oxidation Evolution and Activity Origin of N-Doped Carbon in the Oxygen Reduction Reaction

N-doped carbon materials,with their applications as electrocatalysts for the oxygen reduction reaction(ORR),have been extensively studied.However,a negletcted fact is that the operating potential of the ORR is higher than the theoretical oxida-tion potential of carbon,possibly leading to the oxidation of carbon materials.Consequently,the infl uence of the structural oxidation evolution on ORR performance and the real active sites are not clear.In this study,we discover a two-step oxida-tion process of N-doped carbon during the ORR.The fi rst oxidation process is caused by the applied potential and bubbling oxygen during the ORR,leading to the oxidative dissolution of N and the formation of abundant oxygen-containing functional groups.This oxidation process also converts the reaction path from the four-electron(4e)ORR to the two-electron(2e)ORR.Subsequently,the enhanced 2e ORR generates oxidative H_(2)O_(2),which initiates the second stage of oxidation to some newly formed oxygen-containing functional groups,such as quinones to dicarboxyls,further diversifying the oxygen-containing functional groups and making carboxyl groups as the dominant species.We also reveal the synergistic eff ect of multiple oxygen-containing functional groups by providing additional opportunities to access active sites with optimized adsorption of OOH*,thus leading to high effi ciency and durability in electrocatalytic H_(2)O_(2) production.

Tin-mediated carbon-confined Pt_(3)Co ordered intermetallic nanoparticles as highly efficient and durable oxygen reduction electrocatalysts for rechargeable zinc-air batteries

The development of electrocatalysts for the oxygen reduction reaction(ORR) that bears high selectivity,exceptional activity,and long-term stability is crucial for advancing various green energy technologies.Intermetallics composed of platinum and transition metals are considered to be promising candidates for this purpose.However,they typically face challenges such as unfavorable intrinsic activity and a propensity for particle aggregation,diminishing their ORR performance.Against this backdrop,we present our findings on a N-doped carbon confined Pt_(3)Co intermetallic doped with p-block metal tin(Pt_(3)Co_(x)Sn_(1-x)/NC).The introduction of Sn induces lattice strain due to its larger atomic size,which leads to the distortion of the Pt_(3)Co lattice structure,while the coupling of carbon polyhedra inhibits the particle aggregation.The optimized Pt_(3)Co_(0.8)Sn_(0.2)/NC catalyst demonstrates an impressive half-wave potential of 0.86 V versus RHE,surpassing both Pt_(3)Co/NC and Pt_(3)Sn/NC catalysts.Moreover,the Pt_(3)Co_(0.8)Sn_(0.2)/NC exhibits a mass-specific activity as high as 1.4 A mg_(Pt)^(-1),ranking it in the top level among the intermetallicsbased ORR electrocatalysts.When further employed as a cathode material in a self-assembled zinc-air battery,it shows stable operation for over 80 h.These results underscore the significant impact of lattice strain engineering through the strategic doping of p-block metal in the carbon-confined Pt_(3)Co intermetallic,thereby enhancing the catalytic efficiency for the ORR.

Central environmental protection inspection and carbon emission reduction: A tripartite evolutionary game model from the perspective of carbon neutrality

Since the carbon neutrality target was proposed,many countries have been facing severe challenges to carbon emission reduction sustainably.This study is conducted using a tripartite evolutionary game model to explore the impact of the central environmental protection inspection(CEPI)on driving carbon emission reduction,and to study what factors influence the strategic choices of each party and how they interact with each other.The research results suggest that local governments and manufacturing enterprises would choose strategies that are beneficial to carbon reduction when CEPI increases.When the initial willingness of all parties increases 20%,50%—80%,the time spent for the whole system to achieve stability decreases from 100%,60%—30%.The evolutionary result of“thorough inspection,regulation implementation,low-carbon management”is the best strategy for the tripartite evolutionary game.Moreover,the smaller the cost and the larger the benefit,the greater the likelihood of the three-party game stability strategy appears.This study has important guiding significance for other developing countries to promote carbon emission reduction by environmental policy.

Advances in Polymeric Carbon Nitride Photocatalysts for Enhanced CO_(2)Reduction

Photocatalysis has emerged as a promising alternative for converting and utilizing CO_(2).Polymeric carbon nitride(PCN),typically synthesized through the one-step thermal polycondensation of nitrogen-rich precursors,has shown considerable promise due to its adjustable band structure and inherent safety.Over the past five years,significant literature in this field has identified five primary methods for modifying PCN:morphology modulation,element doping,defect induction,co-catalyst loading,and heterojunction construction.A detailed discussion on how each modification method influences light absorption,charge separation,and surface reaction efficiencies in photocatalysis is provided.Based on these findings,several future directions for the development of PCN-based materials are proposed,such as designing tailored PCN structures for specific photocatalytic reactions and using theoretical calculations to verify and correct results from current characterization methods.Despite the challenges associated with the large-scale synthesis of PCN materials with controllable structures and satisfactory performance,this work offers valuable insights for advancing photocatalytic PCN-based systems for large-scale solar fuel production.

Poly(ethylenimine)-assisted synthesis of hollow carbon spheres comprising multi-sized Ni species for CO_(2) electroreduction

Electrochemical CO_(2) reduction to produce value-added chemicals and fuels is one of the research hotspots in the field of energy conversion.The development of efficient catalysts with high conductivity and readily accessible active sites for CO_(2) electroreduction remains challenging yet indispensable.In this work,a reliable poly(ethyleneimine)(PEI)-assisted strategy is developed to prepare a hollow carbon nanocomposite comprising a single-site Ni-modified carbon shell and confined Ni nanoparticles(NPs)(denoted as Ni@NHCS),where PEI not only functions as a mediator to induce the highly dispersed growth of Ni NPs within hollow carbon spheres,but also as a nitrogen precursor to construct highly active atomically-dispersed Ni-Nx sites.Benefiting from the unique structural properties of Ni@NHCS,the aggregation and exposure of Ni NPs can be effectively prevented,while the accessibility of abundant catalytically active Ni-Nx sites can be ensured.As a result,Ni@NHCS exhibits a high CO partial current density of 26.9 mA cm^(-2) and a Faradaic efficiency of 93.0% at-1.0 V vs.RHE,outperforming those of its PEI-free analog.Apart from the excellent activity and selectivity,the shell confinement effect of the hollow carbon sphere endows this catalyst with long-term stability.The findings here are anticipated to help understand the structure-activity relationship in Ni-based carbon catalyst systems for electrocatalytic CO_(2) reduction.Furthermore,the PEI-assisted synthetic concept is potentially applicable to the preparation of high-performance metal-based nanoconfined materials tailored for diverse energy conversion applications and beyond.

A thermodynamic view on the in-situ carbon dioxide reduction by biomass-derived hydrogen during calcium carbonate decomposition

In the carbonate industry,deep decarbonization strategies are necessary to effectively remediate CO_(2).These strategies mainly include both sustainable energy supplies and the conversion of CO_(2)in downstream processes.This study developed a coupled process of biomass chemical looping H2 production and reductive calcination of CaCO_(3).Firstly,a mass and energy balance of the coupled process was established in Aspen Plus.Following this,process optimization and energy integration were implemented to provide optimized operation conditions.Lastly,a life cycle assessment was carried out to assess the carbon footprint of the coupled process.Results reveal that the decomposition temperature of CaCO_(3)in an H_(2)atmosphere can be reduced to 780℃(generally around 900℃),and the conversion of CO_(2)from CaCO_(3)decomposition reached 81.33%with an H2:CO ratio of 2.49 in gaseous products.By optimizing systemic energy through heat integration,an energy efficiency of 86.30%was achieved.Additionally,the carbon footprint analysis revealed that the process with energy integration had a low global warming potential(GWP)of-2.624 kg·kg^(-1)(CO_(2)/CaO).Conclusively,this work performed a systematic analysis of introducing biomass-derived H_(2)into CaCO_(3)calcination and demonstrated the positive role of reductive calcination using green H_(2)in mitigating CO_(2)emissions within the carbonate industry.

Sulfur doped iron-nitrogen-hard carbon nanosheets as efficient and robust noble metal-free catalysts for oxygen reduction reaction in PEMFC

Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.

MOF‐derived 1D/3D N‐doped porous carbon for spatially confined electrochemical CO_(2) reduction to adjustable syngas

Electrochemical reduction of CO_(2) to syngas(CO and H_(2))offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals.Herein,the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon(1D/3D NPC)is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge(MS),for electrochemical CO_(2) reduction reaction(CO_(2)RR).The 1D/3D NPC exhibits a high CO/H_(2) ratio(5.06)and CO yield(31 mmol g^(−1)h^(−1))at−0.55 V,which are 13.7 times and 21.4 times those of 1D porous carbon(derived from Zn‐MOF‐74)and N‐doped carbon(carbonized by MS),respectively.This is attributed to the unique spatial environment of 1D/3D NPC,which increases the adsorption capacity of CO_(2) and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon,improving the reaction kinetics of CO_(2)RR.Experimental results and charge density difference plots indicate that the active site of CO_(2)RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon.The presence of pyridinic N and pyrrolic N reduces the number of electron transfer,decreasing the reaction kinetics and the activity of CO_(2)RR.The CO/H_(2) ratio is related to the distribution of N species and the specific surface area,which are determined by the degree of spatial confinement effect.The CO/H_(2) ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect.Given the low cost of feedstock and easy strategy,1D/3D NPC catalysts have great potential for industrial application.

Urban Landscaping Design and Carbon Reduction Planning Countermeasures

As the most significant green ecological resource in densely populated and economically developed areas,urban landscaping plays a pivotal role in carbon sink value and multiple ecosystem service functions.It is a crucial element in the advancement of green and low-carbon initiatives in China’s major cities and the realization of a carbon-neutral vision.By analyzing the relationship between carbon emission reduction and urban landscaping,the paper sorts out and summarizes the basic principles of urban landscaping design,proposes the role of landscape design in urban landscaping,and plans countermeasures for carbon reduction in urban landscaping,with a view to optimizing the construction and management of urban landscaping.

Reduction effect of carbon emission and optimisation path of green finance

Under the background of"dual-carbon",green finance is an important way to promote carbon emission reduction and realize the development of a low-carbon economy.Using provincial panel data from 2000 to 2020,this paper constructs a basic regression model to study the"carbon reduction"effect,mechanism of action,and heterogeneity of green finance.The study finds that:the development of green finance significantly inhibits carbon emissions and has an obvious"carbon reduction"effect;green technology innovation has a mediating effect on the carbon emission reduction effect of green finance;in regions with a high level of economic development or a high degree of marketization,the"carbon reduction"effect of green finance is significant.

Mesoporous Carbon Nanofibers Loaded with Ordered PtFe Alloy Nanoparticles for Electrocatalytic Nitrate Reduction to Ammonia

Highly dispersed bimetallic alloy nanoparticle electrocatalysts have been demonstrated to exhibit exceptional performance in driving the nitrate reduction reaction(NO_(3)RR)to generate ammonia(NH_(3)).In this study,we prepared mesoporous carbon nanofibers(mCNFs)functionalized with ordered PtFe alloys(O-PtFe-mCNFs)by a composite micelle interface-induced co-assembly method using poly(ethylene oxide)-block-polystyrene(PEO-b-PS)as a template.When employed as electrocatalysts,O-PtFe-mCNFs exhibited superior electrocatalytic performance for the NO_(3RR)compared to the mCNFs functionalized with disordered PtFe alloys(D-PtFe-mCNFs).Notably,the NH_(3)production performance was particularly outstanding,with a maximum NH_(3)yield of up to 959.6μmol/(h·cm~2).Furthermore,the Faraday efficiency(FE)was even 88.0%at-0.4 V vs.reversible hydrogen electrode(RHE).This finding provides compelling evidence of the potential of ordered PtFe alloy catalysts for the electrocatalytic NO_(3)RR.

The photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)for stable photocatalytic CO_(2)reduction

Developing suitable photocatalysts and understanding their intrinsic catalytic mechanism remain key challenges in the pursuit of highly active,good selective,and long-term stable photocatalytic CO_(2)reduction(PCO_(2)R)systems.Herein,monoclinic Cu_(2)(OH)_(2)CO_(3)is firstly proven to be a new class of photocatalyst,which has excellent catalytic stability and selectivity for PCO_(2)R in the absence of any sacrificial agent and cocatalysts.Based on a Cu_(2)(OH)_(2)^(13)CO_(3)photocatalyst and 13CO_(2)two-sided^(13)C isotopic tracer strategy,and combined with in situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS)analysis and density functional theory(DFT)calculations,two main CO_(2)transformation routes,and the photo-decomposition and self-restructuring dynamic equilibrium mechanism of Cu_(2)(OH)_(2)CO_(3)are definitely revealed.The PCO_(2)R activity of Cu_(2)(OH)_(2)CO_(3)is comparable to some of state-of-the-art novel photocatalysts.Significantly,the PCO_(2)R properties can be further greatly enhanced by simply combining Cu_(2)(OH)_(2)CO_(3)with typical TiO_(2)to construct composites photocatalyst.The highest CO_(2)and CH_(4)production rates by 7.5 wt%Cu_(2)(OH)_(2)CO_(3)-TiO_(2)reach 16.4μmol g^(-1)h^(-1)and 116.0μmol g^(-1)h^(-1),respectively,which are even higher than that of some of PCO_(2)R systems containing sacrificial agents or precious metals modified photocatalysts.This work provides a better understanding for the PCO_(2)R mechanism at the atomic levels,and also indicates that basic carbonate photocatalysts have broad application potential in the future.

Porous metal oxides in the role of electrochemical CO_(2) reduction reaction

The global energy-related CO_(2) emissions have rapidly increased as the world economy heavily relied on fossil fuels.This paper explores the pressing challenge of CO_(2) emissions and highlights the role of porous metal oxide materials in the electrocatalytic reduction of CO_(2)(CO_(2)RR).The focus is on the development of robust and selective catalysts,particularly metal and metal-oxide-based materials.Porous metal oxides offer high surface area,enhancing the accessibility to active sites and improving reaction kinetics.The tunability of these materials allows for tailored catalytic behavior,targeting optimized reaction mechanisms for CO_(2)RR.The work also discusses the various synthesis strategies and identifies key structural and compositional features,addressing challenges like high overpotential,poor selectivity,and low stability.Based on these insights,we suggest avenues for future research on porous metal oxide materials for electrochemical CO_(2) reduction.

Comprehensive understanding of the thriving electrocatalytic nitrate/nitrite reduction to ammonia under ambient conditions

Ammonia(NH_(3))is a multifunctional compound that is an important feedstock for the agricultural and pharmaceutical industries and attractive energy storage medium.At present,NH_(3)synthesis is highly dependent on the conventional Haber–Bosch process that operates under harsh conditions,which consumes large quantities of fossil fuels and releases a large amount of carbon dioxide.As an alternative,electrosynthesis is a prospective method for producing NH_(3)under normal temperature and pressure conditions.Although electrocatalytic nitrogen reduction to ammonia has attracted considerable attentions,the low solubility of N_(2)and high N≡N cracking energy render the achievements of high NH_(3) yield rate and Faradaic efficiency difficult.Nitrate and nitrite(NO_(x)^(-))are common N-containing pollutants.Due to their high solubilities and low dissociation energy of N=O,NO_(x)^(-)−are ideal raw materials for NH_(3) production.Therefore,electrocatalytic NO_(x)^(-)−reduction to NH_(3)(eNO_(x)RR)is a prospective strategy to simultaneously realise environmental protection and NH_(3) synthesis.This review offers a comprehensive understanding of the thriving eNO_(x)RR under ambient conditions.At first,the popular theory and mechanism of eNO_(x)RR and a summary of the measurement system and evaluation criteria are introduced.Thereafter,various strategies for developing NO_(x)−reduction catalysts are systematically presented and discussed.Finally,the challenges and possible prospects of electrocatalytic NO_(x)^(-1) reduction are outlined to facilitate energy-saving and environmentally friendly large-scale synthesis of NH_(3) in the future.

Single atom Cu-N-C catalysts for the electro-reduction of CO_(2) to CO assessed by rotating ring-disc electrode

The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.

Porously Reduced 2-Dimensional Bi_(2)O_(2)CO_(3) Petals for Strain-Mediated Electrochemical CO_(2) Reduction to HCOOH

Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO_(2)to formic acid(HCOOH),which are composed of petal-shaped Bi_(2)O_(2)CO_(3)(BOC)that spontaneously formed from Bi thin film in aqueous carbonate solution at room temperature.During the electrochemical reduction process,the BOC petals transform to reduced BOC(R-BOC)consisting of individual BOC and Bi domains.Lattice mismatch between both domains induces biaxial strain at the interfaces.Density functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the*OCHO intermediate,reducing the thermodynamic barrier toward CO_(2)conversion to HCOOH.Together with the thermodynamic benefit and the unique nanoporous petal-shaped morphology,R-BOC petals have a superior Faradaic efficiency of 95.9%at-0.8 V_(RHE)for the electrochemical conversion of CO_(2)to HCOOH.This work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO_(2)reduction reaction;such a strategy can be applicable in design of various electrocatalysts.

Progress in electrocatalytic nitrate reduction for green energy:Catalyst engineering,mechanisms,and techno-economic feasibility

Ammonia(NH_(3))is an irreplaceable chemical that has been widely demanded to keep the sustainable development of modern society.However,its industrial production consumes a huge amount of energy and releases extraordinary greenhouse gases(GHGs),leading to various environmental issues.Achieving the green production of ammonia is a great challenge,which has been extensively pursued in the last decade.In this review,the most promising strategy,electrochemical nitrate reduction reaction(e-NO_(3)RR),is comprehensively investigated to give a complete understanding of its development and mechanism and provide guidance for future directions.However,owing to the complex reactions and limited selectivity,a comprehensive understanding of the mechanisms is crucial to further development and commercialization.Moreover,NO_(3)^(-)RR is a promising strategy for simultaneous water treatment and NH_(3)production.A detailed overview of the recent progress in NO_(3)^(-)RR for NH_(3)production with nontransition and transition metal based electrocatalysts is summarized.In addition,critical advanced techniques,future challenges,and prospects are discussed to guide future research on transition metal-based catalysts for commercial NH_(3)synthesis by NO_(3)^(-)reduction.