Foam Cathode Research Articles

Synergistic uranium extraction, organic degradation, and electricity generation by a self-driven photoelectrochemical system with TNR/Si PVC photoanode and copper foam cathode

Herein, we develop a self-driven photoelectrochemical system (SDPS) featuring a TiO2 nanorod array (TNR)/Si photovoltaic cell (Si PVC) photoanode and a porous copper foam (CF) cathode for efficient uranium recovery. Under simulated sunlight illumination, this SDPS simultaneously achieves ∼ 99.4 % UO22+ recovery and ∼ 99.2 % sulfamethoxazole (SMX) removal, with observed rate constant (kobs) value of 0.121 min−1 and 0.029 min−1, respectively, and a maximum power density (Pmax) of 0.89 mW·cm−2 when treating complex wastewater of SMX (10 mg·L−1)-UO22+ (10 mg·L−1). The TNR photoanode absorbs short-wavelength light (λ < 412 nm), generating electron-hole pairs, while the rear Si PVC absorbs transmission light, creating a self-bias potential that drives electrons transfer towards CF cathode, continuously generating electrical energy in the external circuit. The retained holes and derived •OH oxidize SMX, breaking UO22+-SMX complexation, while electrons on the CF reduce UO22+ to insoluble tetravalent uranium (U(IV)) species. This SDPS demonstrates robust performance across varying UO22+ (5 ∼ 40 mg·L−1) and SMX (0 ∼ 40 mg·L−1) concentrations, pH ranges (4 ∼ 8), coexisting ions, and different types of uranium-containing wastewaters, maintaining stability over 20 cycles. It achieves ∼ 97.5 % UO22+ extraction and ∼ 99.8 % SMX removal in simulated seawater, with a Pmax of 1.27 mW·cm−2. This work presents a promising resource strategy for uranium extraction.

Electrodeposition of dense spherical Ni3P on nickel foam cathode enhance nitrate electrochemical reduction via promoting nitrate adsorption

Electrodeposition of dense spherical Ni3P on nickel foam cathode enhance nitrate electrochemical reduction via promoting nitrate adsorption

Electrocatalytic degradation of naphthenic acids using reduced graphene oxide modified nickel foam cathode: Role of surface structure and superoxide radical

In this work, the reduced graphene oxide (RGO) modified nickel foam (Ni-foam) was prepared via the hydrothermal reduction self-assembly method and was applied as the cathode for the effective electrocatalytic (EC) degradation of recalcitrant naphthenic acids (NAs) that are abundantly present in the petroleum industrial wastewater. The Ni@RGO cathode has greatly enhanced the production of H2O2 in the system to boost the degradation of 1-adamantanecarboxylic acid (ACA) that was a model NA compound. Results showed that the EC/Fe(III)/Ni@RGO system achieved complete ACA degradation within 15 min due to its elevated H2O2 generation and Fe(III)/Fe(II) circulation, compared to EC/Fe(III)/Ni-foam and EC/Fe(III)/Graphite systems. Interestingly, abundant ·O2– radicals, which were produced in EC/Fe(III)/Ni@RGO system as a key intermediate for 2e- oxygen reduction reaction (ORR), could effectively accelerate the circulation of Fe(III)/Fe(II) to activate H2O2 to generate ·OH for ACA degradation. Results of material characterization, electrochemical analysis and density functional theory (DFT) calculations showed that Ni@RGO cathode has obtained elevated electron transfer efficiency compared to that of Ni-foam cathode. Surface structure of RGO, such as carbon edge and vacancy with specific configuration, residual –COOH oxygenation groups on RGO surface are main catalytic sites to enhance the capacity of 2e- ORR and electron capture processes in the system. This study provides new insights regarding the synthesis process of catalytic electrodes, the influence of carbon-based material structure on catalytic activity, and the critical role of free radicals in the electro-Fenton system with Ni@RGO cathode

In situ evolution of electrocatalysts for enhanced electrochemical nitrate reduction under realistic conditions

Electrochemical nitrate reduction to ammonia (ENRA) is gaining attention for its potential in water remediation and sustainable ammonia production, offering a greener alternative to the energy-intensive Haber-Bosch process. Current research on ENRA is dedicated to enhancing ammonia selectively and productivity with sophisticated catalysts. However, the performance of ENRA and the change of catalytic activity in more complicated solutions (i.e., nitrate-polluted groundwater) are poorly understood. Here we first explored the influence of Ca2+ and bicarbonate on ENRA using commercial cathodes. We found that the catalytic activity of used Ni or Cu foam cathodes significantly outperforms their pristine ones due to the in situ evolution of new catalytic species on used cathodes during ENRA. In contrast, the nitrate conversion performance with nonactive Ti or Sn cathode is less affected by Ca2+ or bicarbonate because of their original poor activity. In addition, the coexistence of Ca2+ and bicarbonate inhibits nitrate conversion by forming scales (CaCO3) on the in situ-formed active sites. Likewise, ENRA is prone to fast performance deterioration in treating actual groundwater over continuous flow operation due to the presence of hardness ions and possible organic substances that quickly block the active sites toward nitrate reduction. Our work suggests that more work is required to ensure the long-term stability of ENRA in treating natural nitrate-polluted water bodies and to leverage the environmental relevance of ENRA in more realistic conditions.

Insight into the efficient electrochemical reduction of nitrate employing Pd/Ru bimetallic doped copper foam cathode: Selectivity and reliability

Nitrate pollution threatens ecological environment and human health. Electrochemical reduction of nitrate to ammonia using metal-doped modified cathode is a promising technique for nitrate removal. In this work, a bimetallic Ru/Pd-doped Cu foam (CF) electrode was developed for nitrate reduction using cation exchange method. Confirmed by various physio-chemical characterization, it was found that the Ru/Pd-Cu Spongy Copper Foam (SCF) was successfully prepared. In addition, nearly 100 % nitrate removal, 94.07 % NH3 selectivity, and 84.9 % Faradaic efficiency (FE) could be achieved, under the optimized conditions as 100 mg L−1 of initial NO3--N concentration, 0.3 mol L−1 of Na2SO4 as electrolyte and the applied current of 5.42 mA cm−2. Through electrochemical testing and DFT calculation, it was revealed that the bimetallic doping of Ru/Pd facilitate electrocatalytic nitrate reduction reaction (NO3RR) by reducing the energy barriers of the NO3--to-NH3 pathway from 0.81 to 0.56 eV. Besides, the electrode showed excellent stability and anti-toxicity even after 10 repeated NO3RR cycles, since the NH3 yield rate and NH3 selectivity ranged from 0.206 to 0.231 mg h−1 cm−2, 87–96.87 % respectively. After NO3RR, an extended electrochemical oxidation process was implemented to remove ammonia, and nearly 100 % of NH3 was oxidized to N2 without byproducts. Thereby, this study provides a new option for the electrochemical reduction of nitrate to ammonia via cathode modification, to achieve the substantial nitrate removal from nitrate-containing water.

Practical electrochemical hydrogenation of nitriles at the nickel foam cathode.

We report a scalable hydrogenation method for nitriles based on cost-effective materials in a very simple two-electrode setup under galvanostatic conditions. All components are commercially and readily available. The method is very easy to conduct and applicable to a variety of nitrile substrates, leading exclusively to primary amine products in yields of up to 89% using an easy work-up protocol. Importantly, this method is readily transferable from the milligram scale in batch-type screening cells to the multi-gram scale in a flow-type electrolyser. The transfer to flow electrolysis enabled us to achieve a notable 20 g day-1 productivity of phenylethylamine at a geometric current density of 50 mA cm-2 in a flow-type electrolyser with 48 cm2 electrodes. It is noteworthy that this method is sustainable in terms of process safety and reusability of components.

Endogenous iron-enriched biochar loaded nickel-foam cathode in electro-Fenton for ciprofloxacin degradation: performance, mechanism and DFT calculation

Steel mill wastewater sludge, with abundant endogenous iron resources, could be pyrolyzed into iron-enriched biochar (SBC) in one step and loaded onto nickel foam cathode (Ni-Foam) to construct a heterogeneous electro-Fenton system (SBC@Ni-Foam/EF). The purpose of this study were to optimize SBC@Ni-Foam/EF for efficient ciprofloxacin (CIP) removal, and its degradation mechanism and pathway in the presence of endogenous iron were elucidated by DFT calculation. The results showed that the highest CIP degradation efficiency (95.11 %) was achieved at a SBC pyrolysis temperature of 800 °C, an initial solution pH of 3, a Na2SO4 concentration of 0.05 mol L−1, a current density of 40 mA cm−2, and an aeration rate of 200 mL min−1. The degradation of CIP by SBC@Ni-Foam/EF was dominated by cathodic catalytic oxidation, and ·OH played a major role in the CIP degradation process. Combined with characterization and DFT calculation, the endogenous iron was dispersed in the stable Fe3O4 crystalline phase, which provided surface defects and catalytic sites for the cathode and promoted H2O2 activation to generate ·OH through iron cycling. The possible degradation pathways of CIP were proposed to include the cleavage of piperazine and quinolone rings, hydroxylation, and substitution or detachment of fluorine, etc., and the overall toxicity of the intermediates was alleviated after SBC@Ni-Foam/EF treatment. Therefore, this study was expected to achieve a win–win situation for iron-enriched sludge biomass resource utilization and CIP wastewater treatment.

Enhanced electrochemical disinfection for decentralized sewage treatment through nickel foam cathode modified with CoFe2O4-spinel ferrite and multi-way carbon nanotubes

Electrochemical disinfection is characterized by its simple operation and maintenance, along with effective sterilization capabilities, making it ideal for decentralized wastewater treatment in rural areas. As a bimetallic oxide, spinel ferrite exhibits excellent catalytic activity for the oxygen reduction reaction (ORR). Herein, a novel cathode was fabricated from nickel foam modified with spinel ferrite and multi-way carbon nanotubes (CoFe2O4-MWCNTs@NF). The modification successfully strengthens the electrochemical cathode reaction to generate strong oxidants such as hydrogen peroxide and Hydroxyl radical, enabling the disinfection of water bodies with low chloride concentrations. Compared to other influencing factors (including current density, aeration rate, and electrode spacing), the impact of conductivity on hydrogen peroxide generation is relatively minor. Modified electrodes still exhibited effective disinfection capabilities in water with low conductivity. At a current density of 2 mA/cm², the CoFe2O4-MWCNTs@NF electrode achieved 4.00 log removal of E.coli in real treated sewage within 15 minutes, with an energy consumption of 1.038 kWh/m³. Electrochemical disinfection also had a certain degradation ability for sulfonamides and quinolones antibiotics in water. The disinfection and antibiotic removal effects of the modified electrode demonstrated its potential for practical applications.

Electro-assisted heterogeneous peroxymonosulfate activation on NiFe2O4 coated nickel foam cathode for tetracycline degradation: Synergistic efficacy and mechanism

BackgroundThe electro-assisted inverse spinel catalytic peroxymonosulfate (PMS) activation system is a highly promising technology for the degradation of the antibiotic by in-situ and stably produced reactive species. MethodsHerein, a reverse-structured spinel ferrite NiFe2O4 grown on nickel foam (NF) serves as the cathode, and a platinum sheet serves as the anode, constructing a novel ECNiFe2O4/NF-PMS system. Significant FindingsUnder optimal conditions, the system achieves a remarkable 81.7 % degradation of 30 mg/L tetracycline (TC) within 60 min, surpassing other oxidation systems. Comparative radical scavenger experiments under air and N2 conditions reveal that radicals generated from PMS activation, in-situ generated H2O2, and electrode reactions collectively contribute to TC degradation, with 1O2 playing a pivotal role. The introduction of electrochemical reactions promotes ion diffusion, electron transfer and redox cycles of metal active sites, synergistically improving the activity and stability of the heterogeneous PMS activation system. The ECNiFe2O4/NF-PMS system selectively attacks the side aromatic rings of TC, leading to a reduction in the overall ecological toxicity of intermediate products, as confirmed by the Toxicity Estimation Software Tool. Moreover, the system exhibits robust resistance to the interference of coexisting substances, indicating its promising practical application potential for antibiotic degradation.

In situ electro-generated Ni(OH)2 synergistic with Cu cathode to promote direct ammonia oxidation to nitrogen.

To solve the problem of low removal rate and poor N2 selectivity in direct electrochemical ammonia oxidation (EAO), commercial Ni foam and Cu foam were used as anode and cathode of the EAO system, respectively. The coupling effect between the cathode and anode promoted nitrogen cycling during the reaction process, which improved N2 selectivity of the reaction system and promoted it to achieve a high ammonia removal rate. This study showed that the thin Ni(OH)2 with oxygen vacancy formed on the surface of Ni foam anode played an effective role in the dimerization of intermediate products in ammonia oxidation to form N2. This electrochemical system was used to treat real goose wastewater containing 422.5 mg/L NH4+-N and 94.5 mg/L total organic carbon (TOC). After treatment, this electrochemical system achieved good performance with an ammonia removal rate of 87%, N2 selectivity of 77%, and TOC removal rate of 72%. Therefore, this simple and efficient system with Ni foam anode and Cu foam cathode is a promising method for treating ammonia nitrogen wastewater.

Effects of foam cathode electrode structure on alkaline water electrolysis for hydrogen production

Hydrogen is widely recognized as a clean and sustainable energy source. One of the most promising methods for hydrogen production is alkaline water electrolysis. The efficiency and cost-effectiveness of this process heavily depend on the choice of a suitable porous electrode structure. This paper aims to investigate impact of the porous structure on the performance of alkaline electrolytic water through experiments and multi-physics field simulation. Specifically, the whole cell performance test and hydrogen-evolution reaction (HER) test of nickel foam were conducted in an electrolytic cell using 1 M KOH. Results revealed that various parameters of the electrode structure, such as specific surface area, pore density, thickness, and electronic conductivity, significantly influenced the hydrogen evolution. Increasing the specific surface area or pore density proved to enhance the hydrogen evolution under conventional voltage. Reducing the thickness has a similar effect. Additionally, materials with high conductivities increase the reaction rate. Based on experimental results, the optimal nickel foam cathode structure was 1000 μm thickness and 75 PPI pore density. The results of stability tests and electrolysis voltage efficiency analysis provide further support for the positive effect of this structure on hydrogen evolution. This study provides rational reference for designing efficient and stable porous electrode structures.

A combination of microbial electrolysis cells and bioaugmentation can effectively treat synthetic wastewater containing polycyclic aromatic hydrocarbon.

The anaerobic biodegradation of polycyclic aromatic hydrocarbons (PAHs) is challenging due to its toxic effect on the microbes. Microbial electrolysis cells (MECs), with their excellent characteristics of anodic and cathodic biofilms, can be a viable way to enhance the biodegradation of PAHs. This work assessed different cathode materials (carbon brush and nickel foam) combined with bioaugmentation on typical PAHs-naphthalene biodegradation and analyzed the inhibition amendment mechanism of microbial biofilms in MECs. Compared with the control, the degradation efficiency of naphthalene with the nickel foam cathode supplied with bioaugmentation dosage realized a maximum removal rate of 94.5 ± 3.2%. The highest daily recovered methane yield (227 ± 2 mL/gCOD) was also found in the nickel foam cathode supplied with bioaugmentation. Moreover, the microbial analysis demonstrated the significant switch of predominant PAH-degrading microorganisms from Pseudomonas in control to norank_f_Prolixibacteraceae in MECs. Furthermore, hydrogentrophic methanogenesis prevailed in MEC reactors, which is responsible for methane production. This study proved that MEC combined with bioaugmentation could effectively alleviate the inhibition of PAH, with the nickel foam cathode obtaining the fastest recovery rate in terms of methane yield.

Tailoring Ni 3d orbitals in Ni-Fe/Ni foam heterostructures for enhanced H* adsorption and boosted electrocatalytic nitrate reduction performance

The electrochemical nitrate (NO3−) reduction (ENR) in wastewater, a promising remediation strategy, is often impeded by the essential use of costly noble metals. This study introduces an innovative non-noble Ni-Fe/Ni foam cathode fabricated via one-step electrodeposition technique. Efficient nitrate removal (99.4 %) was achieved with the selectivity of 83.6 % to NH3. The exceptional performance can be ascribed to the augmented active sites and the synergistic interaction between Ni and Fe. The leftward shift of the 3d orbitals density of Ni and the elevation of density at the Fermi level on Ni foam heterostructures, consequent to Fe doping, enhance the adsorption of H*. The addition of reactive chlorine species, generated through anodizing in Cl− mediated system, further improves N2 selectivity by oxidizing intermediate NH4+ product. The coupled anodic oxidation method employed herein achieves nearly 100 % removal efficiency of total nitrogen (TN) for initial concentration of 100 mg/L within 180 min, under the conditions of 1.5 g/L Cl− concentration and a current density of 25 mA cm−2. The findings underscore the potential of the Ni-Fe/Ni foam cathode within a Cl− mediated electrocatalytic framework for nitrate wastewater treatment, providing novel insights into the design of cathode catalysts and anodic coupling strategies for efficient TN removal.

Role of microbial electrolysis desalination cell in sustainable water and energy management: Performance assessment of platinum and nickel foam cathodes and simulating integration with reverse osmosis systems

This research introduces the microbial integrated cell (MIC), a bioelectrochemical system that combines microbial electrolysis and desalination for sustainable energy and water purification. Efficiency evaluations of nickel foam and Pt/CC cathodes for hydrogen production and desalination showed nickel foam achieving a 91% desalination efficiency, closely following Pt/CC's 99%, with hydrogen generation rates of 0.96 m3H2/m3/d for Pt/CC cathodes and 0.72 m3H2/m3/d for nickel foam. Despite marginally lower performance, the cost advantages of nickel foam suggest its feasibility for large-scale deployment. Further exploration into MIC integration with reverse osmosis (RO) system aims to enhance the sustainability of the combined system. Simulation outcomes indicate that MIC-RO integration can significantly reduce energy consumption and brine concentration discharged into the sea, highlighting its potential to improve desalination plants' efficiency and environmental impact. This research facilitates the transition of these green technologies to practical applications, optimizing efficiency and environmental benefits.

Efficient removal of ammonia nitrogen via a coupled system of Ni1Cu0.2-Se-T/CP anode and copper foam cathode

Direct electrochemical oxidation is a green, clean and promising process for the treatment of ammonia nitrogen (NH4+-N) wastewater. Nevertheless, drawbacks of slow reaction kinetics and large overpotential greatly limit the ammonia oxidation reaction. To address the issue, Ni1Cu0.2-Se-T/CP was synthesized by the combination of heteroatom doping and in situ electrochemical oxidation (ISEO). Physical characterization shows that there are homogeneous and dense microscopic nanosphere particles on the electrode surface, which provide good attachment sites for the adsorption of reactants. Electrochemical tests further show that this catalytic electrode exhibits not only a high current density (37.17 mA·cm−2) at 0.65 V vs.Hg/HgO but also has the low Tafel slope (92.25 mV·dec−1) to ammonia oxidation reaction. Then, Ni1Cu0.2-Se-T/CP was applied as anode with copper as cathode to construct a coupled system. The area ratio of cathode/anode was optimized to improve the removal effect of ammonia nitrogen. The NH4+-N conversion efficiency of 100% was obtained at a constant anode potential of 0.65 V vs.Hg/HgO for 15 h when the cathode/anode area was 1:4. The system N2 selectivity up to 77.55%. This work provides a promising process for the green and efficient degradation of ammonia nitrogen wastewater.

Kraft lignin-derived multi-porous carbon toward sustainable electro-Fenton treatment of emerging contaminants

Reclaiming biomass waste to carbon cathode is promising to construct a sustainable electrochemical system. Here, we developed a novel thermal foaming process to reform kraft lignin to a free-standing and multi-porous carbon foam, which can be used as carbon cathode for electro-Fenton treatment of emerging contaminants (ECs). Benefiting from the excellent physicochemical and electrochemical properties with multi-porous and graphitic structure, the synthesized carbon foam cathode enhanced the electrocatalytic generation of H2O2 and •OH, and subsequently promoted the mass transfer and interactions among reactants (i.e., O2, H2O2, Fe2+, •OH, natural organic matters, and ECs). Eventually, an efficient degradation of ECs was achieved most likely via the multi-step •OH addition, cleavage, and ring opening reactions. Overall, the outcomes of this work provide a sustainable and applicable design and strategy to upgrade lignin-containing biomass to carbon cathode for efficient ECs remediation.

Surface modified copper foam with cobalt phthalocyanine carbon nanotube hybrids for tuning CO2 reduction reaction products.

The CO2 reduction reaction (CO2RR) is a feasible way to convert this greenhouse gas into molecules of industrial interest. Herein we present the modification of the Cu foam cathode using molecular catalyst hybrid from cobalt phthalocyanine (CoPc) to increase selectivity and stability towards CO2RR products in a flow cell setup.

Electrogeneration of H2O2 through carbon-based ink on Al foam for electro-Fenton treatment of micropollutants in water

In the present work, the catalytic efficiency of inks based on different carbon materials, namely activated carbon (AC), carbon graphite (CG), and carbon black (CB) was investigated for the oxygen reduction reaction (ORR). Additionally, we explored the feasibility of using this ink as a coating for an Aluminum foam (Alfoam) cathode in an electrochemical cell. The goal was to utilize this setup to produce hydrogen peroxide (H2O2) in the electro-Fenton (EF) process, targeting for treating water contaminated with contaminants of emerging concern (CECs).Among the materials investigated, all of them exhibited the ability to facilitate the ORR. However, AC proved to be the most suitable material due to its optimal balance between physical and electrocatalytic properties, thus enabling the formation of H2O2. When the different inks were applied to the surface of aluminum foam, it was observed that only the ink based on carbon black CB achieved a homogeneous distribution with the same ink quantity. As a result, it was observed that the Alfoam/CB electrode exhibited the highest H2O2 generation capacity, producing 45.6 mg L-1, followed by electro-generation of 5.1 mg L-1 using Alfoam/AC and 11 mg L-1 using Alfoam/CG. Furthermore, the application of Alfoam/CB in EF processes allowed for the almost complete degradation of 15 emerging contaminants of concern (CECs) present in secondary effluent. The innovative outcome of this study positions the developed technology as a promising and effective alternative for the treatment of water contaminated with CECs, demonstrating significant potential for industrial-scale application.

Synergistic integration of Bi2O3||CoWO4 for asymmetric supercapattery: A binder-free approach ensuring high endurance cycling stability

Supercapatteries are becoming increasingly popular as energy storage devices due to their remarkable electrochemical characteristics, which combine a high energy storage capacity, similar to batteries, and a high-power output, similar to supercapacitors. In this study, the assembly of Bi2O3/Carbon cloth (anode) and CoWO4/Nickel foam (cathode) electrodes was carried out using a PVA-KOH gel electrolyte. The device operated within a potential range of 1.55 V and exhibited a specific capacity of 423 C/g at a 1 A/g current density. Additionally, the prepared solid-state device showed remarkable electrochemical stability, retaining over 96 % coulombic efficiency and 90 % capacity after 10,000 GCD cycles. Furthermore, the fabricated asymmetric supercapattery demonstrated an energy density of 115.11 Wh/kg and a specific power density of 6005 W/kg. The ability of the fabricated adaptable supercapacitor to power an LED highlights its potential in flexible applications without compromising functionality. This presents a promising outlook for the advancement of electrochemical energy storage devices.

Highly selective electrochemical reduction of nitrate via CoO/Ir-nickel foam cathode to treat wastewater with a low C/N ratio

Thorough nitrate removal from reclaimed water by biological techniques without carbon sources is difficult. Flexible, controllable electrochemical nitrate reduction is widely researched. Herein, ultrathin CoO nanosheets were constructed through amino group induction and orientation. The interfacial electron transfer resistance of two-dimensional CoO was 43.4% lower than that of one-dimensional nanoparticles, resulting in higher current density and improved nitrate reduction efficiency. Nickel foam and IrO2-nickel foam electrodes have almost no effect on nitrate reduction. It is worth noting that iridium loading on CoO (nanosheet) regulated the electronic band structure and generated active atomic H* . The nitrate removal rate increased from 45.1% (CoO (nanoparticle)-nickle foam) and 63.8% (CoO (nanosheet)-nickle foam) to 94.64% (CoO/Ir10 wt%-nickle foam). The proton enhancement effect improved indirect nitrate reduction by atomic H* and increased the NO3--N removal rate to 99.8%. Active chlorine species generated by Cl- in the wastewater selectively converted more than 99% of nitrate to N2, exceeding previous Co-based cathode results. In situ DEMS indicated that electrochemical reduction of nitrate included deoxidation (NO3-→*NO2-→*NO→*N/*N2O→N2) and hydrogenation (*NH2→*NH3→NH4+). The NO3--N removal rate of CoO/Ir10 wt% exceeded 65% during treatment of wastewater treatment plant effluents, verifying the feasibility of electrochemical nitrate reduction with the CoO/Ir10 wt% cathode. A strategy for designing electrochemical nitrate reduction electrocatalysts with excellent potential for full-scale application to treat wastewater treatment plant effluent is provided.