arXiv subjects

Aline B. Trench

Publications and source records attributed to Aline B. Trench.

12 recordsLinked to original sources

arXiv2026

Fe3O4 Nano-octahedra/Vulcan XC72: Optimization and Combination with Solar-Based Electro-Fenton for Progestins Degradation

The widespread presence of synthetic progestins, such as levonorgestrel (LNG) and gestodene (GES), in aquatic environments poses significant ecotoxicological risks due to their endocrine-disrupting properties. In this study, nano-octahedral magnetite (Fe3O4-NO) was synthesized via a hydrothermal route and incorporated into gas diffusion electrodes (GDEs) supported on Vulcan XC72 to enhance the in-situ electrogeneration of hydrogen peroxide (H2O2). High-resolution transmission electron microscopy, X-ray diffraction, SEM, X-ray photoelectron spectroscopy, and contact angle measurements thoroughly characterized the physicochemical and morphological properties of the materials. The 3% Fe3O4-NO/C catalyst provided a two-fold increase in H2O2 selectivity compared with Vulcan XC72. Electrochemical performance was optimized using a 2^3 factorial design and principal component analysis (PCA), with current density, pH, and Na2SO4 concentration as variables. The optimized GDE (3% Fe3O4-NO/C) achieved a maximum H2O2 production of 0.44 +/- 0.02 g L-1 with a current efficiency of 43.1 +/- 0.23% and a specific energy consumption of 0.012 +/- 0.009 kWh g-1. The electrode was further applied to the degradation of LNG and GES using solar and anodic-assisted electro-Fenton processes. Under optimal conditions, over 70% removal of both progestins was achieved, with stable performance across three operational cycles. These findings demonstrate the potential of 3% Fe3O4-NO/C-GDEs as efficient, reusable cathodes for sustainable electrochemical advanced oxidation processes (EAOPs) in water treatment.

physics.chem-ph↗

arXiv2026

Influence of CeO$_2$MnO$_x$ heterostructure on Hydrogen Peroxide Electrogeneration on Carbon-Based Catalysts

The sustainable electrogeneration of hydrogen peroxide (H2O2) via the two-electron oxygen reduction reaction (2e$^-$ ORR) represents a promising alternative to conventional production methods. In this study, CeO2 and CeO2MnOx nanoparticles were synthesized and supported on Vulcan XC-72 carbon at varying loadings (1, 3, and 5%), aiming to assess the lowest metal loading and high H2O2 electrosynthesis. Physicochemical characterizations confirmed the successful formation of CeO2 nanowires and the effectiveness of the MnOx surface modification. XRD, TEM, XPS, EPR, and contact angle analyses revealed that CeO2 loading increased surface hydrophilicity through the presence of oxygenated functional groups, thereby favoring electrochemical activity. On the other hand, all CeO2MnOx loadings were statistically equivalent to Vulcan XC-72 in terms of contact angle. Electrochemical evaluations using a rotating ring-disk electrode (RRDE) demonstrated enhanced ORR activity and high H2O2 selectivity for the 1% CeO2MnOx/C and 3% CeO2/C catalysts, achieving up to 90% selectivity and elevated ring currents. The results suggest that low metal loading and surface modification via MnOx improve the balance between active site exposure, oxygen adsorption, and intermediate stabilization, thus favoring the selective 2e$^-$ pathway. These findings support the development of cost-effective, non-noble-metal catalysts for green H2O2 production via electrosynthesis.

cond-mat.mtrl-sci↗

arXiv2026

Flower-like WO3-modified Vulcan carbon GDEs for photoelectro-Fenton process: Efficient ciprofloxacin degradation and mechanistic insights

Electrochemical H2O2 synthesis was investigated using a 3 percent WO3 C gas diffusion electrode GDE. The catalyst outperformed bare Vulcan carbon, generating H2O2 concentrations of 423, 586, and 916 mg L at 50, 75, and 100 mA cm2, respectively, maintaining around 70 percent current efficiency. This performance and lower energy consumption are attributed to the WO3 carbon synergistic effect. In electro Fenton EF applications, the WO3 C GDE achieved rapid initial ciprofloxacin CIP degradation of around 70 percent in 30 min, though limited later by slow Fe2 regeneration. Incorporating UV light photoelectro Fenton overcame this constraint, yielding complete CIP removal within 90 min, while a boron doped diamond BDD anode enhanced total organic carbon TOC mineralization to 66 percent. The proposed degradation mechanism proceeds via hydroxyl radical attack on the piperazine ring with or without defluorination and quinolone ring oxidation, with theoretical analysis confirming reduced environmental toxicity of the transformation products. Overall, WO3 C GDEs represent a highly efficient strategy for H2O2 generation and wastewater remediation.

cond-mat.mtrl-sci↗

arXiv2026

Electron Paramagnetic Resonance Study of Radical Species on NaNbO3@CeO2-Modified Carbon Vulcan XC72 Gas Diffusion Electrode for Electrochemical Degradation of Paracetamol via Electro-Fenton

While electrochemical oxidation is a promising technology for water treatment, a fundamental understanding of the specific radical mechanisms involved in pharmaceutical degradation has remained limited. This study addresses this gap by employing Electron Paramagnetic Resonance (EPR) spectroscopy to directly quantify the radical species generated during the degradation of paracetamol using a novel gas diffusion electrode (GDE) modified with NaNbO3 nanocubes and CeO2 nanorods. This approach provides a critical advancement beyond prior literature by moving from indirect inference to direct, quantitative analysis of reactive species. Results demonstrated that a boron-doped diamond (BDD) anode (65% OH radical, 35% aryl radicals) drastically outperformed a Platinum (Pt) anode (74% OH radical, 26% aryl radicals), achieving complete degradation in 15 minutes versus 45 minutes and 81.6% versus 67.8% mineralization. Consequently, this work provides a foundational mechanistic framework that fundamentally advances the field, offering not just a more effective material system (BDD/NaNbO3@CeO2-GDE) but also a validated methodology for rationally designing and optimizing electrochemical water treatment processes based on quantifiable radical pathways.

physics.chem-ph↗

arXiv2026

Fe3O4 nano-octahedra and SnO2 nanorods modifying low-Pd amount electrocatalysts for alkaline direct ethanol fuel cells

This work describes the ethanol oxidation reaction (EOR) in alkaline medium using low-palladium nanoparticle electrocatalysts modified by Fe3O4 nano-octahedra and SnO2 nanorods. Operation studies on an alkaline direct ethanol fuel cell (ADEFC) were conducted using the developed electrocatalysts, and stability studies were performed using the advanced scanning flow cell (SFC) technique coupled to inductively coupled plasma mass spectrometry (online SFC-ICP-MS). The EOR was catalyzed by single (Pd/C and commercial Pd/C Alfa Aesar) and by synthesized binary and ternary electrocatalysts, in which Fe3O4 and SnO2 nanostructures partially replaced the high-cost noble metal. The PdFe3O4/C was identified as the most promising synthesized material in the electrochemical studies, exhibiting the highest mass activity (1426 mA mg-1 Pd) by cyclic voltammetry (CV), followed by the binary PdSnO2/C (1135 mA mg-1 Pd), and by the ternary (1074 mA mg-1 Pd). This enhancement was attributed to the bifunctional mechanism enabled by Fe3O4 and SnO2, therefore reducing poisoning and improving the EOR. Moreover, the operating results revealed that PdFe3O4/C showed the highest power density among the synthesized materials (31 mW cm-2 at 70 C), even with an approximately 45 percent reduction in Pd content compared to the commercial catalyst. XPS results showed that the Pd 3d5/2 and 3d3/2 peaks for PdFe3O4/C, PdSnO2/C, and PdFe3O4SnO2/C were shifted by approximately 0.5 eV to higher binding energies compared to Pd/C, indicating a loss of electron density in Pd due to strong metal-oxide interactions.

cond-mat.mtrl-sci↗

arXiv2026

Photo-Assisted Pd-Nb2O5/Carbon Nanocomposites for Enhanced Ethanol Electro-Oxidation Kinetics and CO Tolerance in Alkaline Media

Pd-based anodes for alcohol oxidation suffer from surface poisoning and sluggish kinetics. Here, we developed Pd-Nb2O5/C nanocomposites to improve ethanol electrooxidation kinetics and CO tolerance in alkaline media. Orthorhombic Nb2O5 prepared by the Pechini route was combined with fcc Pd nanoparticles via polyol reduction, yielding Pd(x)-Nb2O5(y)/C nanocomposites with x:y = 100:0, 70:30, 50:50, 30:70, 0:100. Rietveld-refined X-ray diffraction confirmed phase purity and showed similar Pd crystallite sizes (4.46 nm for Pd/C and 4.92-5.08 nm for Nb2O5-containing catalysts). Transmission and scanning electron microscopies coupled with energy-dispersive X-ray spectroscopy reveal uniformly dispersed Pd nanoparticles on Nb2O5 and carbon. UV-Vis diffuse reflectance indicated a band gap of 3.10 eV, and chopped-light photocurrent measurements confirm the strong ultraviolet responsiveness of Nb2O5. X-ray photoelectron spectroscopy reveals that Pd(0.5)Nb2O5(0.5)/C had the highest Pd0 content (58.99%). Electrochemical testing demonstrates that, relative to Pd/C, optimized Pd(0.5)Nb2O5(0.5)/C reduces the ethanol oxidation onset potential by up to 160 mV, increases poisoning tolerance by a factor of five at a fixed potential, and raises the current density from 1.59 to 1.76 mA cm-2. Under light irradiation, the current density increases from 1.07 to 2.10 mA cm-2, accompanied by improved stability and extended durability, attributed to light-induced electron-hole generation and enhanced OH- adsorption. These results highlight the synergistic contribution of oxide-metal interactions and photoactivation to ethanol oxidation and provide insights for designing efficient catalysts for alkaline fuel cells. s

cond-mat.mtrl-sci↗

arXiv2025

Effect of Fluorine doping on the electrocatalytic properties of Nb2O5 for H2O2 electrogeneration

The oxygen reduction reaction (ORR) via the 2-electron mechanism is an efficient way to produce hydrogen peroxide (H2O2) under mild conditions. This study examines the modification of Vulcan XC72 carbon with fluorine (F)-doped niobium oxide (Nb2O5) nanoparticles at varying molar ratios (0, 0.005, 0.01, 0.02). The F-doped Nb2O5 nanoparticles were synthesized using the oxidizing peroxide method and then incorporated into Vulcan XC72 carbon via impregnation. Characterization techniques included X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), contact angle measurements, and X-ray photoelectron spectroscopy (XPS). Electrochemical evaluation using the rotating ring disk electrode method revealed that Vulcan XC72 modified with 1.0% F-doped Nb2O5 exhibited the best ORR performance. When used as a gas diffusion electrode, this electrocatalyst produced more H2O2 at all applied potentials than the pure and Nb2O5-modified Vulcan XC72 carbon. At potentials of -0.7 V and -1.3 V, the proposed electrocatalyst achieved H2O2 yields 65% and 98% higher than the Nb2O5-modified electrocatalyst. Furthermore, it presented lower energy consumption and higher current efficiency than the other electrocatalysts compared in this study. The enhanced performance is attributed to F doping, which increased Nb2O5 lattice distortion and disorder, improving electron availability for ORR. Additionally, F-doped electrocatalysts exhibited more oxygenated species and greater hydrophilicity, facilitating O2 adsorption, transport, and electron transfer. These properties significantly enhanced H2O2 electrogeneration efficiency while reducing energy consumption.

cond-mat.mtrl-sci↗

arXiv2025

Improvement of H$_2$O$_2$ electrogeneration using a Vulcan XC72 carbon-based electrocatalyst modified with Ce-doped Nb$_2$O$_5$

The use of the oxygen reduction reaction (ORR) for in-situ production of H$_2$O$_2$ is an attractive alternative to replace the methods based on anthraquinone oxidation. This study investigates the modification of Vulcan XC72 carbon with Ce-doped Nb$_2$O$_5$ in different molar proportions and its application as electrocatalysts in the ORR. One performed the characterization of the electrocatalysts using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Subsequently, the electrocatalysts were analyzed for the ORR and the Nb$_2$O$_5$ doped with 0.5% Ce showing the highest electrocatalytic response. This electrocatalyst was also employed as a gas diffusion electrode and exhibited more significant H$_2$O$_2$ production at all potentials than the Vulcan XC72 carbon modified solely with Nb$_2$O$_5$. At the applied potentials of -1.3 V and -1.9 V, it produced 105% and 86% more H$_2$O$_2$, respectively, than the Vulcan XC72 carbon modified only with Nb$_2$O$_5$. These results can be attributed to the doping of Nb$_2$O$_5$ with 0.5% Ce, which induces local distortions in the crystal lattice of Nb$_2$O$_5$ due to the difference in ionic radius between Nb$^{5+}$ and Ce$^{3+}$, which combined with increased hydrophilicity and wetting properties, may have facilitated electron transfer and O$_2$ transport, favoring the ORR.

cond-mat.mtrl-sci↗

arXiv2025

Hydrogen peroxide electrogeneration from O2 electroreduction: a review focusing on carbon electrocatalysts and environmental applications

Hydrogen peroxide (H2O2) stands as one of the foremost utilized oxidizing agents in modern times. The established method for its production involves the intricate and costly anthraquinone process. However, a promising alternative pathway is the electrochemical hydrogen peroxide production, accomplished through the oxygen reduction reaction via a 2-electron pathway. This method not only simplifies the production process but also upholds environmental sustainability, especially when compared to the conventional anthraquinone method. In this review paper, recent works from the literature focusing on the 2-electron oxygen reduction reaction promoted by carbon electrocatalysts are summarized. The practical applications of these materials in the treatment of effluents contaminated with different pollutants (drugs, dyes, pesticides, and herbicides) are presented. Water treatment aiming to address these issues can be achieved through advanced oxidation electrochemical processes such as electro-Fenton, solar-electro-Fenton, and photo-electro-Fenton. These processes are discussed in detail in this work and the possible radicals that degrade the pollutants in each case are highlighted. The review broadens its scope to encompass contemporary computational simulations focused on the 2-electron oxygen reduction reaction, employing different models to describe carbon-based electrocatalysts. Finally, perspectives and future challenges in the area of carbon-based electrocatalysts for H2O2 electrogeneration are discussed. This review paper presents a forward-oriented viewpoint of present innovations and pragmatic implementations, delineating forthcoming challenges and prospects of this ever-evolving field.

cond-mat.mtrl-sci↗

arXiv2025

Degradation of methylparaben by anodic oxidation, electro-Fenton, and photoelectro-Fenton using carbon felt-BDD cell

In this study, the comparative efficiency of different electrochemical advanced oxidation processes, such as anodic oxidation with electrogenerated H2O2 (AO- H2O2), electro-Fenton (EF), and its combination with UV irradiation (photoelectron-Fenton (PEF)), was investigated for the removal of methylparaben (MP) using a carbon felt cathode and a boron-doped diamond anode. The EF process achieved a higher MP removal efficiency than the AO-H2O2 process for all applied current densities. The total organic carbon (TOC) removal after 6 h of treatment at a current density of 10 mA cm-2 reached 75.0% and 91.9% for the AO- H2O2 and EF processes, respectively. The combination of EF and UV light improved the efficiency of the EF process. The PEF process achieved a TOC removal of 84.6% in only 2 h at 5 mA cm-2 and 96.8% after 6 h of treatment. Furthermore, based on identifying oxidation reaction intermediates and short-chain carboxylic acids generated during the treatment, a reaction pathway for methylparaben mineralization by hydroxyl radicals was proposed.

physics.chem-ph↗

arXiv2025

Magnetic field-enhanced oxygen reduction reaction for electrochemical hydrogen peroxide production with different cerium oxide nanostructures

We investigated cerium oxide nanoparticles of various morphologies (nanosheets, nanocubes, and nanoparticles) supported on carbon Vulcan XC-72 for the two-electron oxygen reduction reaction (ORR). It was used a continuous magnetic field (2000 Oe) for the first time in the literature. The best results were for 5% (w/w) CeO2 for all three different morphologies, more than doubling the ring current, enhancing the hydrogen peroxide selectivity from 51% (Vulcan XC-72) to 84-89%, and modifying the onset potential to lesser negative values. The presence of the magnetic field led to even higher ring currents with 5% (w/w) CeO$_2$, H$_2$O$_2$ selectivity from 54% (Vulcan XC-72) to 88-96% and changing even more the onset potential. Those results were correlated with the Zeeman effect, the Lorentz force, generating magnetohydrodynamic effects, the Kelvin force, and the formation of Bound Magnetic Polarons. This pioneering research introduces an innovative approach, highlighting the potential of an external continuous magnetic field.

physics.chem-ph↗

arXiv2025

Magnetic field-enhanced two-electron oxygen reduction reaction using CeMnCo nanoparticles supported on different carbonaceous matrices

The current study illustrates the successful synthesis of Ce$_{1.0}$Mn$_{0.9}$Co$_{0.1}$ nanoparticles, characterized through XRD, EPR, magnetization curves, and TEM/HRTEM/EDX analyses. These nanoparticles were then loaded into the carbon Vulcan XC72 and the carbon Printex L6 matrices in varying amounts (1, 3, 5, and 10% w/w) via wet impregnation method to fabricate electrocatalysts for the 2-electron ORR. Before experimentation, the material was characterized via XPS and contact angle measurements. The electrochemical results produced significant findings, indicating that the electrocatalysts with the nanostructures modifying both carbon blacks notably augmented currents in rotating ring-disk electrode measurements, signifying enhanced selectivity for H$_2$O$_2$ production. Moreover, our research underscored the significant impact of Magnetic Field-Enhanced Electrochemistry, employing a constant magnetic field strength of 2000 Oe, on 2-electron ORR experiments. Particularly noteworthy were the observed results surpassing the ones without the magnetic field, demonstrating heightened currents and improved selectivity for H$_2$O$_2$ production (more than 90 %) facilitated by CeMnCo nanoparticles. These significant findings in electrocatalytic efficiency have practical implications, suggesting the potential for developing more efficient and selective catalysts for the 2-electron ORR.

physics.chem-ph↗