Electrochemical Measurements Research Articles

Comparative study of various metal‐based reference electrodes

AbstractThis paper compares materials potentially suitable for preparing solid reference electrodes, which could be used in miniaturized flow electrochemical cells. The tested electrodes are based on Sb, Bi, Pd, Pt, and Ag. The stable potential of the reference electrodes was maintained by the pH of the electrolyte, except for the AgCl electrode, whose potential was given by the concentration of chlorides. The performance of the reference electrodes was evaluated through a series of experiments focusing on potential dependences, long‐term and short‐term stability, cyclic voltammetry, and flow injection analysis with amperometric detection. Potentiometric experiments showed that Sb‐based electrodes had the closest slope to theoretical values with minor changes over five weeks. Theory‐consistent results of potential dependence were also observed for AgCl electrodes. The results of the voltammetric and flow amperometric experiment suggest that Sb‐based reference electrodes are the most suitable tools for electrochemical measurement. AgCl electrodes are limited by the necessity of maintaining a high chloride concentration. Bi‐based and PdH electrodes provide unstable results, the latter particularly due to hydrogen desorption. Although able to provide the stable potential to some extent, Pt electrodes are not suitable as the reference electrodes due to the deformation of mainly hydrodynamic voltammograms.

Electrochemical Na+/K+ Ion Exchange in Zeolitic Vanadium(IV) Borophosphate K1.33Na0.67[VO(B2O)(PO4)2(HPO4)]·1.63H2O as Cathode Material for Sodium-Ion Batteries.

Electrochemical ion exchange has recently been demonstrated to be a unique method for the preparation of novel cathode materials, which cannot be accessible by traditional direct synthesis routes. In this study, the vanadium borophosphate compound K1.33Na0.67[VO(B2O)(PO4)2(HPO4)]·1.63H2O (KNVBP) with zeolitic framework exhibits fast electrochemical Na+/K+ ion exchange when used as cathode material in sodium-ion batteries (SIBs). Ex situ structural analyses and electrochemical measurements confirm that most of the K+ ions in the parent KNVBP can be extracted and exchanged by Na+ ions after the first charge/discharge cycle. The in situ-generated Na-rich phase shows reversible electrochemical activity at approximately 3.9 V versus Na+/Na with a specific capacity of 52.9 mAh g-1, comparable to 96.2% of the theoretical capacity. Moreover, enhanced ionic diffusion kinetics can be achieved after the Na+/K+ exchange. This study provides a valuable insight into the electrochemical ion exchange in polyanion compounds toward application in metal-ion batteries.

Self‐Assembly of MnS Shell on CdTe Nanoparticles Induced by Thermohydrolysis: Synthesis and Characterization

Herein, CdTe/MnS core/shell nanoparticles dispersed in an aqueous solution have been synthesized. The formation of MnS semiconductor shell occurs by spontaneous self‐assembly. This process is activated by thermal hydrolysis that removes the excess of thiol and releases S2− ions. In this process, Mn2+ ions on the surface of the CdTe nanoparticles bind to S2− ions to produce a fine semiconducting layer of MnS. Measurements of Raman spectroscopy, optical absorption, and electrochemical measurements are performed. The Raman spectrum shows CdTe characteristic bands at 141 and 163 cm−1. Bands at 221 and 444 cm−1 are associated with the MnS structure. Cyclic voltammetry and differential pulse voltammetry are used to estimate the electrochemical gap at ≈2.47 eV. Absorption optical measurements show tree absorption bands. A broad band between 460 and 520 nm is associated with the first transition in CdTe nanoparticle. The absorption spectrum reveals an optical gap in the range of 2.41–2.33 eV for all the refluxed samples. These values are consistent with those obtained with the electrochemical measurements. The results evidence the formation of a core–shell semiconducting nanostructure made of CdTe nanoparticles coated with a spontaneously self‐assembled thin layer of MnS nanoparticles.

Investigation of the energy gap and anti-corrosion activities of triethanolamine lauryl sulfate for carbon steel in 1.0 M HCl using DFT theory and electrochemical studies

Corrosion inhibition is a critical strategy in the industry to mitigate the detrimental effects of corrosion. Green inhibitors are a concern and are encouraged to apply in various ways. Triethanolamine lauryl sulfate (TLS) investigates as a green corrosion inhibition for carbon steel in 1 M HCl using weight loss and electrochemical measurements. A weight loss study revealed that 100 μM of TLS had the highest inhibition effectiveness of 95.7 %. Tafel estimations from the polarization profiles showed that 100 μM had an optimal inhibition effectiveness of about 96.3 %. The physical adsorption of TLS on the carbon steel surface, which followed the Langmuir adsorption isotherm, was ascribed to the inhibitive effect. The results declare that TLS functioned as an inhibitor of mixed types. For TLS, the adsorption Gibb's free energy is −19.6 kJ mol−1, indicating spontaneous and physisorption-based. The energy gap of TLS is evaluated theoretically using density functional theory (DFT), and a lower value indicates its great donation ability of electron’s to the carbon steel. The mechanism of adsorption of TLS onto the metal surfaces is illustrated in terms of experimental and theoretical calculations.

Investigation of supercritical CO2 corrosion behavior of X80 carbon steel in pipelines: An in situ experimental and DFT study

The electrochemical corrosion behavior of X80 carbon steel was investigated in a supercritical CO2 (sCO2) environment at 60 ℃ and 9 MPa, by in-situ experiments and density functional theory (DFT) calculations, revealing the corrosion mechanism. For in situ electrochemical measurements, two novel CO2-rich and H2O-rich cells were developed to replace the traditional three-electrode cell. Electrochemical impedance spectroscopy revealed distinct differences in the corrosion behavior between CO2-rich and H2O-rich environments during the later stages of testing. In H2O-rich environments, as corrosion time increased, the corrosion product layer gradually changed from porous to dense, eventually forming a protective layer. In CO2-rich environments, corrosion occurs mainly in areas where water condenses to form FeCO3. Simultaneously, microscopic calculations provided evidence for the three-step sCO2 hydrolysis mechanism and the formation of FeCO3 products.

Label free and ultrasensitive electrochemical detection of carcinoembryonic antigen using a disposable aptasensor based on Pd and graphene

We prepared an electrochemical aptasensor for label-free analysis of carcinoembryonic antigen (CEA). Herein, PdNPs were synthesized on the surface of graphene-modified screen-printed carbon electrodes (Pd-GN/SPCE) via electrochemical method for immobilisation of CEA aptamer as a bio-recognition element. The morphological characterizations of the fabricated Pd-GN/SPCE were performed using SEM, EDX, and elemental mapping that confirmed the successful electrochemical deposition of PdNPs. A disposable aptasensor for ultrasensitive electrochemical measurement of CEA was proposed by immobilising CEA aptamer on Pd-GN/SPCE. The electrochemical measurements were performed using 5 mM [Fe(CN)6]3-/4- as a redox probe. The electrochemical deposition of PdNPs improved the electrical conductivity resulting in enhanced current response for the redox probe. When CEA antigen interacts with CEA aptamer, it reduces the oxidation and reduction current of [Fe(CN)6]3-/4- due to the attachment of biomolecules to the electrode surfaces that hinders the electron transfer. The current changes of the redox species before and after CEA binding were measured using DPV. The developed aptasensor possessed a wide calibration range of 0.002–200 ng/mL and detection limit of 1.0 pg/mL. The aptamer-immobilised electrode provides an exceptional selectivity, reproducibility, and sensitive measurement of CEA. Moreover, the effective sensing of CEA in human serum samples with great recoveries (99.4––106 %) demonstrated its capability for clinical analysis.

A comprehensive electrochemical analysis revealing the surface oxidation behavior difference between pyrite and arsenopyrite

This study systematically investigated the surface oxidation behavior differences between pyrite and arsenopyrite under neutral and alkaline pH conditions using various electrochemical measurements. These measurements include open circuit potential (OCP), cyclic voltammetry (CV), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and Mott-Schottky analyses. Key electrochemical parameters have been obtained. The OCP, oxidation potential (Eox), and charge transfer resistance (Rct) of arsenopyrite and pyrite declined as the solution pH increased, but oxidation current density (jox) and carrier concentration (ND) increased, suggesting that a high solution pH is thermodynamically and dynamically favorable for the oxidation of both pyrite and arsenopyrite. Compared to pyrite, arsenopyrite has a higher Fermi level, lower OCP and Eox, a larger jox, and a smaller Rct at the same pH conditions, suggesting that arsenopyrite oxidation has a higher thermodynamic preference and occurs at a faster rate than pyrite oxidation under neutral and alkaline pH conditions. This comprehensive study enhances our understanding of the oxidation difference between pyrite and arsenopyrite and offers important guidance for the pyrite-arsenopyrite flotation separation when using the selective surface oxidation method.

Effect of TiC grain size on corrosion behaviors of Ti-Si-C nanocomposite coatings fabricated by heterogeneous targets high-power impulse magnetron sputtering

Ti-Si-C coatings with different carbon contents were prepared on SS316L substrates by heterogeneous targets high-power impulse magnetron sputtering with a repetitive C and TiSi deposition. Various tests were employed to analyze the microstructure, anti-corrosion properties in a simulated proton exchange membrane fuel cells (PEMFC) environment and interfacial conductivity of the coatings. Results indicated that the Ti-Si-C coating possessed a typical nanocomposite structure of TiC nanocrystals embedded in amorphous carbon matrix. With the increase of the carbon content, the grain size of TiC nanocrystals was reduced gradually. Electrochemical measurements revealed that a proper decrease of TiC grain size led to an enhanced corrosion resistance of the as-deposited coating. The smallest interfacial contact resistance and corrosion rate of the Ti-Si-C coating in the simulated PEMFC solution reached 5.07 mΩ cm2 and 5.93E-07 A/cm2, respectively. This improvement could be attributed to the formation of a dense and continuous passivation layer composed of Ti2O3 and SiO2 on the top surface of the coating.

In-situ electrochemical upcycling ammonia from wastewater-level nitrate with a natural hematite electrode: Regulation, performance, and application

Electrochemical reduction of nitrate (NO3-RR) to ammonia (NH4+/NH3) offers promising prospects for NO3- treatment. However, this process still suffers from NH4+ causing secondary pollution and catalyst deactivation in high-concentration NO3- wastewater. Herein, a high-performance system comprising a hematite (α-Fe2O3) electrode and a water-resistant membrane achieved 97.6 % NO3- removal and 81.6 % NH4+ as (NH4)2SO4in situ recovery at wastewater-level NO3-. The system exhibited an energy consumption of 62.2 kWh·KgNH3−1 and a Faradaic efficiency of 85.9 %. In-situ spectroscopy and electrochemical measurements revealed that α-Fe2O3 acted as both an electron transfer mediator for reducing NO3- to NO2- and an active center for NH3 formation via NO2-/Fe(Ⅱ) redox. Density functional theory calculations identified *HNO3 to *NO2 as potential-determining step of NO3-RR. Natural hematite-based system exhibited 74.8 % total inorganic nitrogen removal and 77.1 % NH4+ recovery for actual photovoltaic wastewater. This study provides insights into the development of electrochemical systems for resourcefully treating NO3--containing wastewater.

The corrosion behavior of AZ91 bulk alloy and thin films

Purpose The purpose of this study is to campare the corrosion behavior of Az91 films and bulk sample, in the objective to provide reference for the corrosion resistance improvement of Mg alloys. Design/methodology/approach AZ91 films with various thickness values are produced by magnetron sputtering technique, and the corrosion behavior was characterized by immersion tests and electrochemical measurements. Findings The AZ91 films exhibited a preferred orientation with basal planes parallel to the surface and increased densification with the increase of thickness, and a superior corrosion resistance for the AZ91 films compared with the bulk sample. Originality/value The preferred (0002) basal planes in AZ91 films benefited the corrosion resistance and the nanoscale AZ91 films facilitated the development of a dense passivation film. Consequently, AZ91 film exhibited a superior corrosion resistance.

Design of novel electrochemical sensor functionalized with green nanoparticles for tetracycline monitoring

AbstractIncreasing the release of antibiotics in particular tetracycline in the environment is become one of the most concerns that threat human and animals' health. Regarding their low cost, sensitivity, portability, electrochemical sensors have received attention for tetracycline monitoring. With a nanostructure, diverse active functional sites, and good conductivity, green nanoparticles are considered now as an attractive material for sensors design. The objective of the present paper is then the design of electrochemical sensor functionalized with green nanoparticles based on gum Arabic for tetracycline detection. The green nanoparticles are synthesized by direct reduction of silver nanoparticle with gum Arabic polymer. The intrinsic properties of the obtained nanoparticles are examined using different techniques namely UV–Vis absorption (UV), X‐ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric TGA. To follow up, the sensor modification as well as tetracycline detection, cyclic voltammetry (CV) and square wave voltammetry are carried out. Correlation between the different results have demonstrated good dispersion and homogeneity of green nanoparticles, with good applicability in electrochemical measurements. In fact, the sensor has demonstrated wide concentrations range from 0.1 to 1250 nM with a limit of detection in the order of 0.056 nM, lower than those reported in the literature. The selectivity test, investigated against a various interfering with similar structure to tetracycline, have proven a good discrimination between all molecules. In addition, the sensor was successfully applied to real samples, and the found recovery rates are ranging from 90.4% to 106.9%. The obtained results confirm that green nanoparticles based on gum Arabic could commercially be viable for next generation of electrochemical sensor for tetracycline detection, and also could be applied for the detection of the variety of pharmaceutical pollutants in the environment.

Electrodeposition of Crystalline Si Using a Liquid Ga Electrode in Molten KF–KCl–K2SiF6

In this study, the electrodeposition of silicon (Si) using a liquid gallium (Ga) electrode in molten KF–KCl was further investigated. Electrochemical measurements and electrolysis were conducted at 923 K in a KF–KCl–K2SiF6 melt. Cyclic voltammograms at liquid Ga electrodes revealed that the reduction current at 0.6–0.9 V vs K+/K was due to the formation of Si–Ga liquid alloys. Si was deposited via potentiostatic electrolysis at 0.80 V using liquid Ga held in a crucible as an electrode. The Si grains were primarily located at the boundary of the Ga and the crucible, indicating that they were deposited from the Si–Ga liquid alloy. X-ray diffraction confirmed the crystallinity of the deposited Si, with a maximum grain size of approximately 6 mm. Potentiostatic electrolysis at varying charges showed that the Si grain size increased with increased charge, confirming the growth of crystalline Si. The Si grains obtained using the liquid Ga electrode were larger than those obtained using a liquid Zn electrode. Finally, the differences in Si crystal growth rates between the Ga and Zn electrodes were discussed.

Study of anti-corrosion epoxy resin coatings with high corrosion resistance and mechanical performance based on quantum dots

The corrosion of steel construction in marine environments faces severe corrosion threats, and coatings based on nanofillers are an effective strategy for steel corrosion protection. However, the related studies of the anti-corrosion coatings based on quantum dots are still poor. In this work, CuS and ZnS quantum dots (QD) were initially synthesized, and epoxy resin (EP) coatings containing QD with ratios of 0.05 wt%, 0.1 wt%, 0.2 wt%, and 0.5 wt% were successfully prepared subsequently. Surface analysis, electrochemical measurements, salt spray tests, and mechanical tensile tests were performed to characterize the prepared quantum dots and study the anti-corrosion behavior and mechanism of the prepared coatings. Results indicated that the prepared CuS and ZnS quantum dots have small sizes with values of 13.8 and 8.9 nm, respectively. Compared to the pure EP coating, QD-EP coatings have a higher mechanical strength and toughness which is conducive to improving the coatings’ corrosion resistance and service life. The impedance values of all the QD-EP coatings increase by more than three orders of magnitude in contrast to pure EP coating after 60 d of testing. Furthermore, the prepared QD-EP coatings possess a long-term anti-corrosion property.

Influence of doped ions on the electrochemical hydrogen storage properties of LaFeO3-based solid solutions

Perovskite oxides LaFeO3 has been considered as one of the most promising candidates as the negative electrode material of Ni/MH batteries, due to its advantages such as low cost, outstanding corrosion resistance and environmentally friendly. Nevertheless, the low electrical conductivities and poor specific capacities are the main obstacles of developing this material to practical application. Doping is an effective method to solve these problems. In this paper, nanosized LaFeO3-based solid solutions doped with Co3+, Mn3+, and Li+ ions were synthesized via sol-gel method, and the contents of the doped ions are set as 0.10. The substitution positions of the doped ions were discussed. The microstructure tests revealed that the doped samples were single phase structures, and the crystallite sizes of the doped samples were smaller than that of the undoped LaFeO3. The dispersion degrees of the doped samples were improved. The results of the spectra tests demonstrated that the doped ions decreased the band gap energies, the Co3+ and Mn3+ ions influenced the frequencies of Fe–O stretching vibrations, and partial replacement of La3+ ions by Li+ ions induced the shift of vibration modes of the La–O bond. Electrochemical hydrogen storage measurements showed that the doped samples possess significantly better properties than that of the undoped LaFeO3. Thereinto, the maximum discharge capacity of the Co3+ ion doped sample reached to 414 mAh/g at the 14th cycle and remained stable at around 400 mAh/g within the following cycles. Kinetic results further proved that the doped samples showed better performances. The hydrogen storage properties of doped LaFeO3 are closely associated with the contents of the oxygen vacancies and defects in the lattice of samples. In addition, the characteristics of the doped ions also play important roles in improving the hydrogen storage properties of the LaFeO3-based oxides.

Mg-Ti hybrid joints: Surface modification, corrosion studies and 3D-pore investigation using synchrotron-based microtomography

A new direction toward the future of orthopedic implants is to combine biodegradable Mg alloys with permanent Ti to produce selectively biodegradable hybrid joints for advanced tissue engineering. However, the strong galvanic corrosion between Mg and Ti is a major issue to be considered. This work aims to explore plasma electrolytic oxidation (PEO) as a single-step coating treatment to allow for an acceptable degradation behavior of MgTi hybrid systems. To this end, MgTi hybrid joints were produced through the heat treatment of Mg-0.6Ca and commercially pure Ti specimens at 640 °C for 8 h. A single-step PEO treatment was then employed to create a protective layer on the surface of hybrid couples. Even though the scanning electron microscopy (SEM) images showed only a porosity of 6% and 12% within the PEO layers on single Mg and MgTi couples, 3D investigation of the synchrotron-based microtomography data demonstrated a porosity of 18% and 30% with a considerable number of interconnected pores. According to the electrochemical impedance spectroscopy measurements, the impedance modulus at all frequencies on coated MgTi coupled specimens was lower than that on the coated single Mg-0.6Ca and pure Ti. However, the application of PEO treatment significantly decreased the strong galvanic degradation of Mg-0.6Ca in contact with Ti. The results of hydrogen evolution tests revealed that PEO-treated MgTi couples showed a similar degradation behavior as the single alloy during the first day of immersion.

Electronic structure, photocatalytic and electrochemical performance of chalcogenide quantum dots loaded on reduced graphene oxide: (Cu2MnSnS4/rGO)

In the present article, facile and novel synthesis of Cu2MnSnS4/reduced-graphene (CMTS/rGO) nanocomposites is achieved. X-ray diffraction (XRD), Raman analysis, X-ray photoelectron spectroscopy (XPS) were explored to test the supposed formation. CMTS semiconductors grow within a tetragonal symmetry and rGO crystallize into hexagonal phase. CMTS particle size is very small having dimensions around 10–12 nm and corroborates with the average particle size calculated from the SEM. The TEM micrograph of rGO consists ∼10 nm thick nanosheets. The composite materials exhibit 2D morphology with 17 nm thick rGO nanosheets holding CMTS quantum dots (9 nm). Electronic structure modulations with rGO specify the replication of energy band gaps with experimental agreements. Photocatalytic activity against malachite green (MG) enhances from 74 % (CMTS) to 95 % (CMTS/rGO). In addition, the electrochemical measurements demonstrate the specific capacitance for 10 % CMTS/rGO (870 F/g) is about four times larger than that of pure CMTS (268 F/g). Our results prompt the evidence of possible applications and further research in photocatalysis via graphene reduction.

MoSe2 nanosheets-based sensor for electrochemical detection of dopamine, ascorbic acid, and uric acid

There has been a growing interest in the field of transition metal dichalcogenide (TMD) materials and their potential applications in the field of electrochemical sensors. In the present work, molybdenum diselenide (MoSe2), as a typical representative of TMD, was prepared using a facile hydrothermal method and characterized in terms of its morphological and structural properties. Then, the obtained MoSe2 was dispersed in various solvents to investigate its electrocatalytic properties towards dopamine (DA), ascorbic acid (AA), and uric acid (UA). The electrochemical measurements revealed that deionized water is an effective solvent to disperse the MoSe2 and modify electrodes with the MoSe2 for electrochemical applications. Furthermore, the glassy carbon electrode (GCE) modified with the MoSe2, referred as GCE-MoSe2, was used as an electrochemical sensor to simultaneously detect the DA, AA, and UA. The GCE-MoSe2 exhibited wide linear detection with concentration ranges of 1–333 µM for DA, 50–3440 µM for AA, and 5–1146 µM for UA in phosphate buffer solution and low detection limits (LODs) of 0.57 µM, 13.7 µM, and 1.75 µM, respectively. The electrode further displayed good selectivity, reproducibility, and stability. This work provides valuable insights on constructing electrochemical sensing devices with high analytical performance using the important two-dimensional (2D) TMD materials.

Cobalt-iron Co-doped ammonium phosphomolybdate for electrocatalytic oxygen evolution in acidic electrolyte

In this study, we investigate the performance of cobalt-iron co-doped phosphomolybdate (CoFe–PMo) as an efficient electrocatalyst for oxygen evolution reaction (OER) in acidic electrolyte. We demonstrate that the introduction of cobalt and iron ions into the phosphomolybdate structure enhances its catalytic activity towards OER. The electrochemical measurements reveal that CoFe–PMo exhibits remarkable stability and improved catalytic activity compared to the undoped amminium phosphomolybdate. The overpotential for OER is only 223 mV at 10 mA cm−2, which is even smaller than that of IrO2.The durable tests maintain its performance over 40 h electrolysis period that the current barely drops. This enhanced performance is attributed to the internal redox between doped cobalt-iron ions and Mo ions in PMo, which promotes the charge transfer and enhances the active sites for OER. The results suggest that CoFe–PMo is a promising catalyst for efficient water splitting in acidic electrolyte, highlighting the potential of cobalt-iron co-doped ammonium phosphomolybdate as a cost-effective and durable electrocatalyst for water splitting for H2 energy in acidic electrolytes.

Zn-BTA complex-plugged halloysite nanocontainers for construction of stimuli-responsive epoxy coating

A strategy is proposed to construct stimuli-responsive halloysite nanotubes (HNTs) inhibitor containers in this study. After the benzotriazole (BTA) corrosion inhibitor was loaded into the etched nanotubes (EHNTs), insoluble Zn-BTA complexes as plugs are formed at both ends of the nanotubes by the interaction of BTA with Zn2+ ions (Zn-BTA@EHNTs). The nanocontainers exhibit good pH-sensitivity. At the lowered pH, the extraction of BTA from the nanocontainers is rapid. By contrast, at the neutral pH, the release rate of BTA is relatively slow. Through the electrochemical measurements for the scribed coatings, it is demonstrated that the Zn-BTA@EHNTs-incorporated epoxy coating exhibits distinct stimuli-responsive behavior. And the incorporation of the Zn-BTA@EHNTs remarkably improves the corrosion resistance of the epoxy coating.

Modification of nickel foam with nickel phosphate catalyst layer via anodizing for boosting the electrocatalytic urea oxidation and hydrogen evolution reactions

Urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) are the key processes for implementing urinated water electrolysis and hydrogen green production, respectively. This contribution investigates the modification of commercial nickel foam (NF) with a nickel phosphate (NiPO/NF) heterostructure layer via anodizing in phosphate solution at various potentials (5, 10 and 15 V) as a simple and efficient route to boost the urea-assisted water electrolysis and hydrogen production in alkaline medium. The morphology and composition physicochemical characterisation of the phosphate layer exhibit aggregates of crystalline nanoparticles with interstitial mesoporous and macroporous networks with a mole composition ratio of 9.42: 1.0: 8.14 for Ni: P: O respectively. The electrochemical measurements revealed the NiPO/NF anodized at 10 V exhibits a superior electroactive surface area of 255 cm2, a substantially higher urea oxidation current compared to pristine NF, achieving 20 and 500 mA/cm2 at 1.35 and 1.6 V vs. RHE respectively and retained 100 % of activity during the urea electrolysis for more than 3 h. The electrochemical impedance analysis confirmed the alkaline urea oxidation reaction proceeded via indirect (EC) and direct mechanism and the CO2 intermediates adsorption–desorption became the predominant reaction at more positive potential. The NiPO/NF anode employed in an H-shape can deliver up to ±400 mA/cm2 for UOR/HER at a bias potential of 1.85 V and 8-fold (2.0 mmol/min) much higher hydrogen production rate compared to the pristine NF anode (0.25 mmol/min). Combining commercial nickel foam modification via anodizing and alkaline urea electrolysis at ambient conditions offers a unique and innovative solution for both large-scale hydrogen green production as well as remedy of the urinated wastewater for a more sustainable future.