Hydrothermal Synthesis Research Articles

Controllable Synthesis of Magnetic Composite Derived from MIL-88D and Study on Adsorption Properties of Cu2+

In this paper, MIL-88D (Fe) with spindle shape was prepared by the hydrothermal synthesis method, a metal oxide with a new structure was obtained by calcination at different temperatures as a precursor, and a magnetic iron oxide composite was prepared successfully. At the same time, it was used as an adsorption material for the adsorption of heavy metal ions Cu2+. The influence of the initial pH value and adsorption time on the adsorption effect was investigated, the adsorption kinetics and adsorption isotherm were further fitted, and the adsorption mechanism was preliminarily analyzed. The results show that the magnetic iron oxide composites have a good adsorption capacity for Cu2+. The pH value is an important parameter that affects the adsorption effect. The adsorption of Cu2+ by magnetic iron oxide composites reached adsorption equilibrium in 30 min. The adsorption of Cu2+ by magnetic iron oxide composites conforms to the second-order reaction kinetics and Langmuir adsorption isotherm equation, which indicates that the adsorption process mainly occurs through chemisorption and typical single-molecular-layer adsorption.

An europium complex assembled by a flexible derivative of imidazole-4,5-dicarboxylic acid as a fluorescence turn-off chemosensor to detect Cr(VI) anions

A new europium(III) CP [Eu(HBBIDA)(H2O)]n (1) (H4BBIDA = 1,1′-(butane-1,4-diyl)bis(1H-imidazole-4,5-dicarboxylic acid) was successfully constructed by hydrothermal synthesis method and detailed characterization was performed. Crystal structure analysis reveals that CP 1 presents a 2D layered structure composed of cage-like SBUs with a TiS2 topological network. CP 1 can maintain framework integrity in an air environment below 260 °C, as well as in a certain pH range of acid-base aqueous solutions and common organic reagents, showing better thermal and chemical stability. Fluorescence measurements show that CP 1 exhibited excellent sensing activities toward CrO42− and Cr2O72− anions through fluorescence quenching, and their average quenching Ksv values of 3.99 × 103 M−1 (CrO42−) and 4.36 × 103 M−1 (Cr2O72−) and the LOD of 3.30 × 10−6 M (CrO42−) and 3.02 × 10−6 M, which makes it very suitable for the detection of hexavalent chromium anions contaminants in aqueous solutions. Furthermore, possible sensing mechanisms have been studied and discussed in detail, and the results show that static photocompetitive absorption should be the primary cause for the fluorescence quenching of the sensor.

ZnO nanostructures grown from spent batteries: Ambient catalytic aspects and novel mechanistic insights

The present work includes a facile and economic microwave assisted hydrothermal synthesis of Zinc Oxide (ZnO), Diethylene Triamine Pentaacetic Acid (DTPA) stabilized Zinc Oxide (ZD) and DTPA stabilized Silver doped Zinc Oxide (ZAD) nanostructures using Zn from spent alkaline batteries. The synthesised nanostructures were well characterised using electronic, vibrational and X-Ray spectroscopic techniques as well as thermal and microscopic techniques revealing the successful stabilisation of DTPA in ZD and doping of Ag in ZAD. The Fourier Transform Infrared Spectroscopy (FTIR) spectra showed peaks characteristic to the presence of ZnO in the fingerprint region and those to the presence of DTPA. The X-Ray Diffraction Spectroscopy (XRD) pattern of ZnO, ZD and ZAD indicated the hexagonal wurtzite structure of ZnO and face centred cubic metallic Ag in ZAD. The Transmission Electron Microscopy (TEM) images revealed rod shaped morphology for ZnO and spherical morphologies for ZD and ZAD. The nanostructures proved to be efficient catalysts to achieve 100 % degradation of Malachite Green, Crystal Violet and Reactive Blue-21 and their binary mixtures under ambient conditions in presence of Hydrogen peroxide (H2O2). ZAD exhibited relatively rapid degradation with rate constants 0.754 min−1, 0.187 min−1 and 0.0150 min−1 for MG, CV, and RB-21 respectively as well as 99 % reduction in Chemical Oxygen Demand (COD) value of the dye solutions. Scavenging studies and Electron Paramagnetic Resonance (EPR) studies using different spin trapping agents revealed the involvement of singlet oxygen species, hydroxyl radicals (OH.) and superoxide radicals (O2.-) in the degradation process. This work aligns with Sustainable Development Goals 6, 12 and 13.

Silicon quantum dots based fluorescent probes for detecting methyl parathion pesticide residues in potato, tap water and Yellow River

In this paper, a novel ratiometric fluorescent probe based on silicon quantum dots (SiQDs) has been developed for the sensitive detection of methyl parathion pesticide residues. The silicon quantum dots were prepared by a simple hydrothermal reaction process using 3-Aminopropyltriethoxysilane (APTES) as silicon resource and were characterized by the analysis of transmission electron microscopy, FTIR spectroscopy, and X-ray photoelectron spectroscopy. The silicon quantum dots displayed characteristic blue fluorescence emission at 440 nm. Tyrosinase can catalyze the oxidation of tyramine to form dopamine. Then, dopamine can interact with silicon quantum dots and effectively change the position of its fluorescence emission for redshiftting to 540 nm. In the presence of organic phosphorus pesticides (OPPs), the activity of tyrosinase was inhibited, resulting in the inability to generate dopamine and the fluorescence emission at 440 nm remaining unchanged. As a model of organic phosphorus pesticides, methyl parathion (MP) was determined using this method, and the fluorescence intensity response values showed a good linear relationship with methyl parathion concentration in the range of 50–90 nM, with a detection limit of 0.149 nM. Due to its good performance of relative low detection limit, good selectivity and high reproducibility, this sensing system has been successfully applied to the detection of methyl parathion in environmental water samples and potato samples, which showed good prospects for application in the detection of organic phosphorus pesticide residues in more real samples.

Effectively enhanced photocatalytic hydrogen production performance of novel noble metal-free Cu(OH)2/MoSe2-g-C3N4 ternary nanocomposite under visible light irradiation

The present work presents a novel copper hydroxide-molybdenum diselenide-carbon nitride (3 % Cu(OH)2/MoSe2-g-C3N4, (3CM-CN)) ternary nanocomposite catalyst. This catalyst was synthesized using a three-step process: hydrothermal synthesis, ball milling, and wet impregnation. The focus of this research is on the hydrogen generation (H₂) capabilities of this novel material. The catalyst was extensively characterized using various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectroscopy, photoluminescence (PL) spectroscopy, and X-ray photoelectron spectroscopy (XPS), resulting in a comprehensive understanding of its structure, morphology, optical properties, and surface composition. The catalytic activity and mechanism of Cu(OH)2/MoSe2-g-C3N4 composites were investigated. The ternary nanocomposite catalyst significantly enhanced hydrogen production, achieving rates 7.7 times greater than g-C3N4 and 4 times greater than 3 % Cu(OH)2/MoSe2 (3CM). Its maximum production reached an impressive 3012 µmol g−1 h−1. The analysis demonstrated a significant increase in active sites on the composite’s surface, accompanied by an increase in the composite-specific surface area to 73 m2/g. The development of a ternary nanocomposite led to a higher rate of catalyst production for hydrogen generation while simultaneously decreasing the rate of electron-hole recombination. It gave an innovative strategy for constructing highly efficient composite catalysts for hydrogen generation very effectively.

NiO-Incorporated Cu/Cu2O Nanowires for Highly Efficient Electrochemical Nitrate Reduction to Ammonia.

Electrochemical nitrate reduction to ammonia (NRA) is a promising sustainable way to synthesize ammonia (NH3) from nitrate (NO3-) contaminants. Cu-based electrocatalysts are frequently utilized for NRA due to their strong NO3- adsorption and de-oxygenation ability. However, this kind of catalyst usually possesses the weak water dissociation ability, resulting in insufficient proton supply in alkaline media to retard the following hydrogenation step of O-containing intermediates (*NOx, typically NO2-) to target NH3. Herein, NiO-incorporated Cu/Cu2O nanowires grown on nickel foam (p-CuNi@NF, p refers to plasma treatment) were synthesized via hydrothermal growth and subsequent O2 plasma treatment for efficient NRA electrocatalysis. On this p-CuNi@NF catalyst, NiO is able to accelerate the hydrogenation step by promoting the water dissociation to provide protons, ultimately facilitating efficient NRA. p-CuNi@NF exhibits excellent NH3 selectivity and yield in a wide potential range and reaches a high Faradaic efficiency (FENH3) of 97.5% and a yield (YNH3) of 470 μmol h-1 cm-2 at -0.6 V, both of which largely surpass the Cu/Cu2O catalyst.

Hydrothermal synthesis of CdTe quantum dots using ammonia as a reducing agent

Hydrothermal synthesis of CdTe quantum dots using ammonia as a reducing agent

Trace rGO-Induced Self-Template Hydrothermal Synthesis of δ-MnO2/C Microspheres as Efficient Cathode for Quasi-Solid Zinc-Ion Batteries

Trace rGO-Induced Self-Template Hydrothermal Synthesis of δ-MnO₂/C Microspheres as Efficient Cathode for Quasi-Solid Zinc-Ion Batteries

Synthesis of multifunctional rGO/g-C3N4/FeTiO3 ternary nanocomposites for photocatalyst, antibacterial, and ecotoxicity assessment of zebrafish embryo model

The wastewater from the dye and pharmaceutical industries antibiotics has caused serious environmental and health problems for humans and other species. For the development of superior photocatalysts, effective separation of photogenerated electron-hole pairs is essential in addition to optimizing solar absorption throughout a wide wavelength range. In order to produce bare, rGO/g-C3N4, rGO/FeTiO3, and rGO/g-C3N4/FeTiO3 (GCNFeT NCs) nanocomposites, this study describes the fabrication of perovskite-type titanate (FeTiO3) and its incorporation onto graphitic carbon nitride (g-C3N4) and reduced graphene oxide (rGO) using a hydrothermal synthesis technique. The generated nanocomposites structural, morphological, and optical properties were evaluated. After being exposed to solar light for 90 min, the resultant GCNFeT NCs efficiently broke down 80 % of Tetracycline (TC) and 90 % of Malachite Green (MG) dye. The photocatalytic efficacy is significantly improved by these results when compared to the pure and binary composites. Substantial catalytic efficiency to GCNFeT NCs was shown by the degradation rate constant (k) for MG and TC elimination by GCNFeT NCs, which was almost 20 times greater than that of pure and binary composites. Additionally, the antibacterial activity of GCNFeT nanocomposites was studied, and the results showed that it was significantly more efficient against Gram-negative bacteria than Gram-positive bacteria, including Escherichia coli and Staphylococcus aureus. Furthermore, the freshwater zebrafish embryo development proved effective in assessing the non-toxicity of GCNFeT NCs. Our research findings indicate that high doses, GCNFeT NCs induce less toxicity in zebrafish embryo (6.25–100 µg/L). These results demonstrated the enhanced mechanism of GCNFeT NCs, indicating their great potential for use in antibacterial and water remediation applications.

Sulfur vacancy riched pure 2H phase VS2 for efficient electrocatalytic hydrogen evolution

Vanadium disulfide (VS2), a typical metallic layered transition metal chalcogenide (TMC), has been widely concerned for its high electrical conductivity and reactivity in electrochemical energy storage and conversion applications. The 2H phase VS2 is expected to exhibit high electrocatalytic activity and be more stable for hydrogen evolution reaction (HER) than the 1T phase structure. But at present, there still lacks a facile method to prepare pure 2H phase VS2. Herein, we successfully prepared pure 2H–VS2 through a simple one-step low-temperature hydrothermal method. We have investigated the effect of the hydrothermal reaction conditions (including the proportion of raw materials and hydrothermal reaction temperatures) on the phase composition and microstructure. Under the optimal condition of 140°C-24 h with a vanadium sulfur ratio of 1:5, a nano-flower-like 2H–VS2 material with high crystallinity and rich sulfur vacancy defects was obtained. Leveraging these structural advantages, as a demonstration, the product exhibits excellent electrocatalytic HER activity (with η10 of 181 mV, Tafel slope of 52 mV dec−1, and J0 of 67.9 × 10−3 mA cm−2) and stability (it can continuously produce hydrogen for 20 h at a current density of 50 mA cm−2 with ultra-small increased potential of less than 5 mV). This work provides a new way for constructing atomic vacancy defects in layered TMCs for efficient electrocatalysis and is also expected to promote the research of the basic properties of high phase purity TMCs.

Revealing the role of 1T- & 2H- molybdenum Disulfide/Nickel sulfide heterojunction for efficient overall water splitting

In the ongoing quest for cost-effective and durable electrocatalysts for hydrogen production—a critical element of sustainable energy transformation—the 1T phase of Molybdenum Disulfide (MoS2) faces challenges due to its thermodynamic instability and the trade-off between efficiency and durability. Conversely, the 2H phase of MoS2, often disregarded in favor of the metallic 1T phase, suffers from its inert nature and limited active sites. To overcome these limitations, this study employs a straightforward hydrothermal synthesis strategy that couples both 1T and 2H phases of MoS2 with Ni3S2, forming 1T- and 2H- MoS2/Ni3S2 heterojunctions. Enhanced by Ni3S2′s abundant active sites, improved electron transport capabilities, synergistic interface effects, and better structural stability, these heterojunctions achieve a high current density exceeding 500 mA cm−2 at low overpotentials, along with prolonged durability for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolytes. Remarkably, an electrolyzer assembly utilizing 1T-MoS2/Ni3S2 as the cathode and 2H-MoS2/Ni3S2 as the anode demonstrates a competitive voltage of 1.58 V at 20 mA cm−2, showcasing superior performance in overall water splitting compared to other non-noble metal-based electrocatalysts. This study not only offers a viable method for synthesizing efficient and stable electrocatalysts for water splitting using transition metal-based heterogeneous structures but also addresses the fundamental challenges associated with 1T and 2H phases of MoS2.

Hydrothermal Synthesis of a Valence State Constant High-Entropy Perovskite Sr(TiZrHfVNb)O3 with Improved Photoresponsiveness.

A vanadium ion valence state constant high-entropy perovskite system was synthesized using the hydrothermal method with a trivalent vanadium ion as the vanadium source. The B-site of the perovskite crystal lattice was loaded with five atoms in equal proportions. We tried to synthesize the Sr(TiZrHfVNb)O3 high-entropy system using different methods. However, the valence state of the vanadium ion could only be kept constant using the hydrothermal process in the valence balanced high-entropy composition system. There was significant vanadium element segregation and second phase in the Sr(TiZrHfVNb)O3 system prepared using the solid-state reaction process. Also, obvious vanadium ion valence state ascending from V3+ to V5+ appeared in this high-entropy system with an increase in calcination temperature. Inconspicuous vanadium element segregation appeared at 900 °C, the significant segregation phenomenon and second phase appeared at 1200 °C, and the particle size increased with the temperature. This meant that the high-entropy value could not only stabilize the crystal phase, but also stabilize the ionic valence state. Moreover, the constant trivalent vanadium ion valence state could provide coordinated performance with a wide optical response range and a low band gap for the high-entropy system. This suggests that the system might grow a potential ceramic material for optical applications.

Plasma-sprayed high entropy alloy coating with novel MoS2 /resin hybrid sealant: Tribological and corrosion characterization

Sealing treatment provides a strategy for the long-term performance of thermal spray coatings under actual working conditions. However, common sealants are mainly limited to improving the corrosion resistance of coatings, neglecting applications in more complex environments where they are subject to simultaneous corrosion and wear. Herein, a novel organic-inorganic hybrid composite sealant, composed of self-lubricating MoS2 nanoparticles and environmentally friendly waterborne silicone modified acrylic resin (WBS-ACR), was successfully prepared in the pores and micro-defects of plasma-sprayed HEA coatings by one-step hydrothermal method. The results indicate that MoS2 nanosheets are uniformly synthesized in resin materials through precursor hydrothermal reactions. The hybrid sealants are filled densely in the micro-defects of HEA coatings with a maximum penetration depth greater than 180 μm. The tribological and electrochemical results indicate that the hybrid sealant exhibits similar anti-wear performance, but two orders of magnitude lower corrosion currents than that of pure MoS2 sealant. In comparison to the pure resin sealant, the hybrid sealant retains its excellent corrosion resistance while increasing its wear resistance. The superior comprehensive performance of the novel organic-inorganic hybrid sealant could expand the application of thermal spray coatings into new fields.

Ag-MOF Nanocatalyst for the Asymmetric Hantzsch Synthesis of Polyhydroquinolines Under Green Conditions

A highly efficient and stable heterogeneous coordination polymer (CP) catalyst was successfully prepared by hydrothermal reaction of silver and 4,6-Diamino-2-pyrimidinethiol, using amine, thiol and pyrimidine functional groups. Besides, silver ions were coordinated to the ligand functional groups in order to give a novel Ag-CPs catalyst. Besides, it was characterized using FT-IR, XRD, TGA, SEM, EDX, X-ray mapping and BET analysis. The prepared Ag-CPs exhibit excellent catalytic activity for multicomponent Hantzsch synthesis of polyhydroquinolines under mild reaction condition in relatively short reaction times. The heterogeneity of the catalyst was confirmed by the hot filtration test and, then, the catalyst was reused for at least four times under the optimized conditions without any significant loss of its activity.

Formation Mechanism and Hydrothermal Synthesis of Highly Active Ir1-xRuxO2 Nanoparticles for the Oxygen Evolution Reaction.

Iridium dioxide (IrO2), ruthenium dioxide (RuO2), and their solid solutions (Ir1-xRuxO2) are very active electrocatalysts for the oxygen evolution reaction (OER). Efficient and facile synthesis of nanosized crystallites of these materials is of high significance for electrocatalytic applications for converting green energy to fuels (power-to-X). Here, we use in situ X-ray scattering to examine reaction conditions for different Ir and Ru precursors resulting in the development of a simple hydrothermal synthesis route using IrCl3 and KRuO4 to obtain homogeneous phase-pure Ir1-xRuxO2 nanocrystals. The solid solution nanocrystals can be obtained with a tunable composition of 0.2 < x < 1.0 and with ultra-small coherently scattering crystalline domains estimated from 1.3 to 2.6 nm in diameter based on PDF refinements. The in situ X-ray scattering data reveal a two-step formation mechanism, which involves the initial loss of chloride ligands followed by the formation of metal-oxygen octahedra clusters containing both Ir and Ru. These octahedra assemble with time resulting in long-range order resembling the rutile structure. The mixing of the metals on the atomic scale during the crystal formation presumably allows the formation of the solid solution rather than heterogeneous mixtures. The size of the final nanocrystals can be controlled by tuning the synthesis temperature. The facile hydrothermal synthesis route provides ultra-small nanoparticles with activity toward the OER in acidic electrolytes comparable to the best in the literature, and the optimal material composition very favorably combines low overpotential, high mass activity, and increased stability.

Construction of ultra-thin NiMo3S4 nanosheet sphere electrode for high-performance hybrid supercapacitor

The construction of electrode materials with rational morphology and structure based on bimetallic sulfides is crucial to improve the performance of supercapacitors. Ultra-thin three-dimensional nickel molybdenum sulfide nanosheet spheres (NiMo3S4 NSSs) are grown on nickel foam (NF) using a one-step hydrothermal synthesis. NiMo3S4 NSSs have a diameter of ∼ 5 μm and nanosheet thickness of 200 nm. The effects of increasing the hydrothermal synthesis time and molar concentration ratios of Ni2+ to MoO42- on the morphologies of the NiMo3S4 are investigated. Due to the synergistic effect of NiMo3S4 NSSs and bimetallic ions which can provide a larger solution contact areas and improve the redox activity, the electrode exhibits good electrochemical properties. The specific capacity of NiMo3S4 NSSs/NF electrode can reach 1002.4 C/g (1 A/g). After being assembled into a hybrid supercapacitor (HSC) with activated carbon (AC), the energy density can reach 72.1 Wh/kg at the power density of 749.9 W/kg. In addition, the HSC shows an excellent stability of 89 % after 10, 000 charge-discharge cycles (10 A/g).

Long-term superhydrophobic, antibacterial, and corrosion-resistant Ag-loaded LiAl-LDH composite coating grown in-situ on MAO coating

This study successfully prepared long-term superhydrophobic, antibacterial, and corrosion-resistant lithium aluminum layered double hydroxide (LiAl-LDH) modified with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) through a hydrothermal reaction. The LiAl-LDH was in situ grown on the micro-arc oxidation (MAO) film and loaded with Ag nanoparticles. The results showed that at a hydrothermal reaction temperature of 150 °C, LiAl-LDH effectively filled the microscopic defects of the MAO coating, significantly enhancing its hydrophobicity. After PFOTES treatment, the water contact angle remained above 150° even after 75 days of immersion in simulated seawater. Additionally, the introduction of Ag+ notably improved the antibacterial properties of the coating. Electrochemical tests indicated that the corrosion resistance of the coating increased with higher hydrothermal temperatures. The corrosion current density of the coating obtained at 150 °C was measured at 2.30 × 10−9 A∙cm−2, which is two orders of magnitude lower than that obtained at 100 °C. Following hydrophobic modification, the corrosion current density decreased further, and after 50 days of immersion in simulated seawater, the |Z|0.01Hz value remained above 108 Ω·cm2, demonstrating excellent corrosion resistance. This study provides important experimental and theoretical foundations for developing metal surface protective coatings with broad application prospects.

Dye-sensitized NiO photocathode sensor based on signal-sensitive change strategy for MC-LR detection.

A novel photoelectrochemical (PEC) sensor for the detection of microcystic toxins (MC-LR) was developed on the basis of signal-sensitive change strategy. NiO nanoarray as a basic photoactive material was grown directly on the ITO glass electrode via calcination after hydrothermal reaction, while dye N719 was used to sensitize the electrode for enhancing visible light absorption, and the first signal-on stage was obtained. In the meantime, p-type Cu2O was applied as the signal probe attached to probe DNA (DNA2) to improve the sensitivity, and the second "signal-on" stage appeared because of its synergistic effect with NiO nanoarrays. The PEC signal decreases after the target analyte MC-LR is modified on the electrode due to the stronger affinity between MC-LR and its complementary aptamer DNA; part of the Cu2O-DNA2 will dissociate from the electrode. This sensitive signal change strategy allows the detection limit of the MC-LR sensor to be as low as 1.7pM, which offers an optional method for the sensitive and selective detection of other target molecules, with potential applications in environmental monitoring and toxin determination.

Hydrothermal synthesis of melamine-based porous organic polymer for the advanced adsorption of iodine

The release of carbon dioxide into the atmosphere from the combustion of fossil fuels to produce energy contributes to severe climate change. Transitioning from fossil fuels to nuclear energy, which is free of carbon emissions, presents its own set of challenges, particularly the potential release of radioactive iodine in handling nuclear waste and in the instance of a nuclear accident. The ongoing research aimed to harness the advantages of porous organic polymers to capture iodine generated during nuclear fission by synthesizing them in an environmentally friendly and cost-effective hydrothermal process. Herein, a melamine-based porous organic polymer (MPOP-4), possessing reliable thermal and chemical stability, highly porous (SABET=195.48 m2/g), designed for iodine capture, is reported. The synthesis of MPOP-4 using melamine and uracil as basic building blocks showed high iodine vapor capture capacities in various media (6.30 g/g at 80 °C, 4833.15 mg/g from aqueous solution, and 1.98 g/g at 25 °C), accompanied by good regeneration ability. A significant abundance of nitrogen content, conjugated π-electron arrangement, and porous network make it an efficient iodine adsorbent. This study suggests the green nature (metal-free) of MPOP-4 and its ability to adsorb iodine.

Physical insight into the enhanced urea electrooxidation using Ni and Fe-based LDH, LDO, and hydroxides under different dissolved gas saturation conditions in electrolyte

The production of green hydrogen is one of the most demanding and challenging for modern technology. A promising and an effective approach is electrocatalytic anodic urea oxidation reaction to generate hydrogen at cathode under alkaline electrolysis condition. However, it remains crucial for the development of active and stable electrocatalysts for efficient urea oxidation. In this study, we employed the hydrothermal synthesis route for NiFe LDH, NiFe LDO, and Ni(OH)2. The superior performance of NiFe LDH compared to other catalysts is observed due to easy charge transfer facilitated by Fe ions. Moreover, Fe incorporation prevents surface poisoning of the electrocatalyst, resulting in increased activity and stability for electrocatalytic urea oxidation reaction. The influence of different electrolyte environments on the performance of urea-based electrolyzers for sustainable hydrogen production and management of urea-rich wastewater has been measured for the first time by varying oxygen saturation and nitrogen purging conditions. In cyclic voltammetry studies, O2-saturated and purging conditions outperformed N2 gas saturation or purging. The findings of this study provide valuable insight into the design of practical and environmentally friendly urea electrooxidation systems.