Oxidation Potential Research Articles

Thermal treatment under oxidative conditions increases the antioxidant and antiglycation activity of Chilean Tórtola beans (Phaseolus vulgaris)

The influence of oxygen on the thermal treatment (TT) of secondary metabolite-enriched extracts (SMEEs) from Tórtola beans and procyanidin C1 (PC1) on the inhibition of advanced glycation end products (AGEs) generation in proteins was investigated. SMEE was incubated at 4 °C (control) or thermally treated at 60 °C for 2 h, at either 0 % O2 (I) or 20 % O2 (II). Treatments I and II increased the content of procyanidin dimers B2. Treatment II was more effective than the control or treatment I in preventing homocysteine oxidation and AGEs generation. TT of PC1 at 0 % or 20 % O2 generated procyanidin dimers and tetramers. PC1 TT at 20 % O2 exhibited higher oxidation potentials and lower IC50 values of fluorescent AGEs than those of controls or TT at 0 % O2. These findings indicate that SMEE from Tórtola beans after treatment II changes the degree of polymerization and oxidation procyanidins, thereby increasing their antiglycation activity.

Evaluating the influence of Nano-GO concrete pavement mechanical properties on road performance and traffic safety using ANN-GA and PSO techniques

The burgeoning demand for durable and eco-friendly road infrastructure necessitates the exploration of innovative materials and methodologies. This study investigates the potential of Graphene Oxide (GO), a nano-material known for its exceptional dispersibility and mechanical reinforcement capabilities, to enhance the sustainability and durability of concrete pavements. Leveraging the synergy between advanced artificial intelligence techniques—Artificial Neural Networks (ANN), Genetic Algorithms (GA), and Particle Swarm Optimization (PSO)—it is aimed to delve into the intricate effects of Nano-GO on concrete's mechanical properties. The empirical analysis, underpinned by a comparative evaluation of ANN-GA and ANN-PSO models, reveals that the ANN-GA model excels with a minimal forecast error of 2.73%, underscoring its efficacy in capturing the nuanced interactions between GO and cementitious materials. An optimal concentration is identified through meticulous experimentation across varied Nano-GO dosages that amplify concrete's compressive, flexural, and tensile strengths without compromising workability. This optimal dosage enhances the initial strength significantly, and positions GO as a cornerstone for next-generation premium-grade pavement concretes. The findings advocate for the further exploration and eventual integration of GO in road construction projects, aiming to bolster ecological sustainability and propel the adoption of a circular economy in infrastructure development.

Eco-Friendly Waterborne Polyurethane Coating Modified with Ethylenediamine-Functionalized Graphene Oxide for Enhanced Anticorrosion Performance.

This study explores the potential of graphene oxide (GO) as an additive in waterborne polyurethane (WPU) resins to create eco-friendly coatings with enhanced anticorrosive properties. Traditionally, WPU's hydrophilic nature has limited its use in corrosion-resistant coatings. We investigate the impact of incorporating various GO concentrations (0.01, 0.1, and 1.3 wt%) and functionalizing GO with ethylenediamine (EDA) on the development of anticorrosive coatings for carbon steel. It was observed, by potentiodynamic polarization analysis in a 3.5% NaCl solution, that the low GO content in the WPU matrix significantly improved anticorrosion properties, with the 0.01 wt% GO-EDA formulation showing exceptional performance, high Ecorr (-117.82 mV), low icorr (3.70 × 10-9 A cm-2), and an inhibition corrosion efficiency (η) of 99.60%. Raman imaging mappings revealed that excessive GO content led to agglomeration, creating pathways for corrosive species. In UV/condensation tests, the 0.01 wt% GO-EDA coating exhibited the most promising results, with minimal corrosion products compared to pristine WPU. The large lateral dimensions of GO sheets and the cross-linking facilitated by EDA enhanced the interfacial properties and dispersion within the WPU matrix, resulting in superior barrier properties and anticorrosion performance. This advancement underscores the potential of GO-based coatings for environmentally friendly corrosion protection.

Linker Conformation Controls Oxidation Potentials and Electrochromism in Highly Stable Zr-Based Metal-Organic Frameworks.

The development of tailor-made electrochromic (EC) materials requires a large variety of available substances with properties that precisely match the task. Since the inception of electrochromic metal-organic frameworks (MOFs), the field relies only on a limited set of building blocks, providing the desired electrochromic effect. Herein, we demonstrate for the first time the implementation of a Piccard-type system (N,N,N',N'-benzidinetetrabenzoate) into Zr-MOFs to obtain electrochromic materials. With fast switching rates, high contrast ratio, long-life stability, and exceptional chemical and physical stability, the novel material is on par with inorganic EC material. The new EC system exhibits an ultrahigh contrast from the bleaching state, with transmittance in the visible region >53%, to the colored state with a transmittance of ca. 3%. The 5 μm thick film attained up to 90% of the coloring in 12.5 s and exhibited high electrochemical reversibility. Moreover, the conformational lability of the electrochromic ligand chosen is locked via the topology design of the framework, which is not attainable in the solution. Locked conformations of the redox active linker in distinct polymorphous frameworks (DUT-65 and DUT-66) feature different redox characteristics and opens the door to the overarching control of the oxidation pathway in the Piccard-type systems.

Calculations of the conversion factor from organic carbon to organic matter for aerosol mass balance

Aerosol mass balance studies based on filter samples require a conversion factor to derive organic matter (OM) concentrations from organic carbon (OC) measurements from thermo-optical methods. This factor provides indirect insights on the molecular structure of OM needed in chemical transport models. Site- and season-specific ratios of OC to OM (fOM:OC) were calculated using data from five rural background sites in France between 2012 and 2021 by relating the unidentified chemical fraction in PM2.5 samples to thermo-optical OC concentrations. Further, multiple linear formulations were used to evaluate the impact of possible artefacts on the determination of fOM:OC. The resulting fOM:OC was then compared to other estimates derived from online aerosol mass spectrometry data, showing good agreement. The spatial and temporal variability in fOM:OC is discussed considering factors such as seasonality, meteorological conditions and the atmospheric oxidative potential. Linear-mixed effect models were formulated to quantitatively determine the drivers which influence the fOM:OC at the French rural background sites. Both ozone and relative humidity were variables with statistically significant effects on fOM:OC, indicating that differences in the contributions from both photooxidation and water content, explain the variability in fOM:OC observed at the French rural background sites. Site-specific fOM:OC yielded more accurate PM2.5 mass closure and are therefore recommended in mass-balance exercises. Accurate fOM:OC are critical to maintain consistency in OM time series, especially in cases where filter-based time series may be replaced by state-of-the-art online instrumentation.

Development of a New Permanganate/Chlorite Process for Water Decontamination.

Development of new technologies with strong selectivity for target pollutants and low sensitivity toward a water matrix remains challenging. Herein, we introduced a novel strategy that used chlorite as an activator for Mn(VII) at pH 4.8, turning the inert reactivity of the pollutants toward Mn(VII) into a strong reactivity. This paved a new way for triggering reactions in water decontamination. By utilizing sulfamethoxazole (SMX) as a typical pollutant, we proposed coupled pathways involving electron transfer across hydrogen bonds (TEHB) and oxidation by reactive manganese species. The results indicated that a hydrogen bonding complex, SMX-ClO2-*, formed through chlorite binding the amino group of SMX initially in the TEHB route; such a complex exhibited a stronger reduction capability toward Mn(VII). Chlorite, in the hydrogen bonding complex SMX-ClO2-*, can then complex with Mn(VII). Consequently, a new reactive center (SMX-ClO2--Mn(VII)*) was formed, initiating the transfer of electrons across hydrogen bonds and the preliminary degradation of SMX. This is followed by the involvement of the generated Mn(V)-ClO2-/Mn(III) in the reduction process of Mn(VII). Such a process showed pH-dependent degradation, with a removal ratio ranging from 80% to near-stagnation as pH increased from 4.8 to 7. Combining with pKa analysis showed that the predominant forms of contaminants were crucial for the removal efficiency of pollutants by the Mn(VII)/chlorite process. The impact of the water matrix was demonstrated to have few adverse or even beneficial effects. With satisfactory performance against numerous contaminants, this study introduced a novel Mn(VII) synergistic strategy, and a new reactivity pattern focused on reducing the reduction potential of the contaminant, as opposed to increasing the oxidation potential of oxidants.

Calibrating the Oxidative Capacity of Microdroplets

Recently, redox reactions have been reported to occur spontaneously in microdroplets. The origins of such reactivity are still debated, and any systematic correlation of the yield with the reactivity of the reactant is yet to be established. We report the simple, outer‐sphere, one‐electron oxidation of a series of ferrocene derivatives spanning oxidation potentials from −0.1 V to +0.8 V vs. Ag/AgCl generated via nebulization and measured by mass spectrometry of the ferrocenium ions. The reaction environments and dynamics in the droplets are complex, and it is still unclear whether such reactivity correlates with bulk thermodynamic values. Our key finding is that the ion yields decrease monotonically with the oxidation potential of the ferrocenes, which is a thermodynamic quantity. The ion yields emphatically do not obey the Nernstian ratio, revealing the redox processes in the droplets do not follow the assumptions of bulk steady‐state electrochemistry. Furthermore, oxidative competition in the mixture of several ferrocenes suggest a finite oxidative capacity or oxidant concentration. These results demonstrate that even though ion generation could be an out‐of‐equilibrium and kinetically limited process, the oxidative yield in microdroplets does correlate with thermodynamics, suggesting a possible free energy relationship between the kinetics and thermodynamics of the process.

Calibrating the Oxidative Capacity of Microdroplets.

Recently, redox reactions have been reported to occur spontaneously in microdroplets. The origins of such reactivity are still debated, and any systematic correlation of the yield with the reactivity of the reactant is yet to be established. We report the simple, outer-sphere, one-electron oxidation of a series of ferrocene derivatives spanning oxidation potentials from -0.1 V to +0.8 V vs. Ag/AgCl generated via nebulization and measured by mass spectrometry of the ferrocenium ions. The reaction environments and dynamics in the droplets are complex, and it is still unclear whether such reactivity correlates with bulk thermodynamic values. Our key finding is that the ion yields decrease monotonically with the oxidation potential of the ferrocenes, which is a thermodynamic quantity. The ion yields emphatically do not obey the Nernstian ratio, revealing the redox processes in the droplets do not follow the assumptions of bulk steady-state electrochemistry. Furthermore, oxidative competition in the mixture of several ferrocenes suggest a finite oxidative capacity or oxidant concentration. These results demonstrate that even though ion generation could be an out-of-equilibrium and kinetically limited process, the oxidative yield in microdroplets does correlate with thermodynamics, suggesting a possible free energy relationship between the kinetics and thermodynamics of the process.

P15-25 Short-term effects of polystyrene nanoplastics on lymph node endothelial cells: insights on oxidative and inflammatory potential

P15-25 Short-term effects of polystyrene nanoplastics on lymph node endothelial cells: insights on oxidative and inflammatory potential

Glass fiber-based metal organic gel composite electrolytes for solid-state lithium batteries

Abstract Quasi-solid-state electrolytes encounter great obstacles in structural stability due to their inherent heterogeneity. Here, we introduce a new composite structure of glass-fiber-based metal-organic gel as a solid-state electrolyte and explore its electrochemical properties in lithium-metal batteries. We use a straightforward in-situ sol-gel method to synthesize this composite electrolyte, where glass fiber acts as matrices, ferric nitrate reacts with trimeric acid to form interconnected channels with abundant unsaturated metal sites, while ionic liquid electrolyte is in-situ confined into interconnected channels. The as-prepared composite electrolyte membrane has a uniform structure and composition, exhibiting a high room-temperature ionic conductivity of 1.79×10−3 S cm−1 and a high electrochemical oxidation potential of 4.76 V vs Li/Li+. This composite has excellent cycling performance in LiFePO4//Li (99.5% after 100 cycles) and NCM811//Li (86.6% after 200 cycles) batteries.

Peculiarities of 7-hydroxyflavone oxidation in relation to our model for the estimation of the first oxidation potential of flavonoids.

Peculiarities of 7-hydroxyflavone oxidation in relation to our model for the estimation of the first oxidation potential of flavonoids.

Electrocatalytic methanol oxidation by Au nanoparticles decorated nickel tungstate/oxide nanocomplexes

The methanol oxidation reaction (MOR) serves as a critical determinant of the energy conversion efficiency within direct methanol fuel cells (DMFC). Consequently, the development of cost-effective and efficient electrocatalysts is paramount for enhancing energy conversion efficiency associated with MOR. The nanomaterials with diverse metal atomic molar ratio of (Ni:W) were synthesized via hydrothermal method for the immobilization of Au nanoparticles (Au NPs) onto the sample surface. The crystal structure of nanocomposites was confirmed through X-ray diffraction (XRD), and transmission electron microscopy (TEM) images depicted a specific surface topography. The catalytic performance of the synthesized catalysts in the MOR was assessed through electrochemical analysis. Notably, catalyst with the Ni:W atomic ratio of 2:1, displayed superior electrocatalytic performance when compared to catalysts possessing other different metal ratios. Moreover, chronoamperometry tests conducted over 7200 s and Tafel slope analysis demonstrated the enduring activity and strong resistance to toxicity of the synthesized catalysts. These results highlight the potential of nickel-tungstate bimetallic oxide as an exceptionally efficient catalyst in the field of electrocatalysis.

Electrochemical sensor for quick and binder-free detection of vitamin B7 using shock waves treated hydroxyapatite/graphene oxide nanocomposite

We report the fabrication of a novel electrochemical sensor for rapid and accurate determination of Vitamin B7 (biotin) using shockwaves treated hydroxyapatite/graphene oxide (SW-HAP/GO) composite modified glassy carbon electrode. Square wave voltammetry measurements at SW-HAP/GO modified GCE exhibits a strong peak at 1.45 V corresponding to the oxidation potential of biotin in phosphate buffer saline at pH 7.0. The results revealed a systematic increase in oxidation peak current with the increase in biotin concentration over a wide range of 16.7–611 µM and the lowest detection limit of 0.215 µM has been deduced. The practicability of the developed sensor has been demonstrated by determining biotin in vitamin B7 tablets, farm fresh groundnuts, dried groundnuts, almonds, pumpkin seeds, and egg yolk. The nuts and seeds samples (10 g each) were soaked in demineralised water for about 10 hours at room temperature and the extracts were used directly for SWV measurements. In all the cases, the SWV revealed a broad peak at about 1.4 V indicating the presence of biotin and from the calibration curves, the actual amount of B7 dissolved in water have been estimated as 1.46, 1.18, 0.43, 4.2, and 5.1 mcg in 10 g of farm fresh groundnuts, dried groundnuts, almonds, pumpkin seeds and egg yolk. Among the investigated samples, pumpkin seeds contain higher amount of biotin and it remained intact even after boiling in water. The fabricated SW-HAP/GO sensor offers potential for quick and precise determination of biotin in food and pharmaceutical industries without requiring streptavidin or antibody.

Osteoinductive potential of graphene and graphene oxide for bone tissue engineering: a comparative study

BackgroundBone defects, especially critical-size bone defects, and their repair pose a treatment challenge. Osteoinductive scaffolds have gained importance given their potential in bone tissue engineering applications.MethodsPolycaprolactone (PCL) scaffolds are used for their morphological, physical, cell-compatible and osteoinductive properties. The PCL scaffolds were prepared by electrospinning, and the surface was modified by layer-by-layer deposition using either graphene or graphene oxide.ResultsGraphene oxide-coated PCL (PCL-GO) scaffolds showed a trend for enhanced physical properties such as fibre diameter, wettability and mechanical properties, yield strength, and tensile strength, compared to graphene-modified PCL scaffolds (PCL-GP). However, the surface roughness of PCL-GP scaffolds showed a higher trend than PCL-GO scaffolds. In vitro studies showed that both scaffolds were cell-compatible. Graphene oxide on PCL scaffold showed a trend for enhanced osteogenic differentiation of human umbilical cord Wharton’s jelly-derived Mesenchymal Stem Cells without any differentiation media than graphene on PCL scaffolds after 21 days.ConclusionGraphene oxide showed a trend for higher mineralisation, but this trend is not statistically significant. Therefore, graphene and graphene oxide have the potential for bone regeneration and tissue engineering applications. Future in vivo studies and clinical trials are warranted to justify their ultimate clinical use.Graphical abstract

Dual isotope analysis reveals the COVID-19 lockdown impact on nitrate aerosol sources and formation pathways in Shanghai

Nitrate (NO3−) is an important contributor to PM2.5 which can adversely affect the environment and human health. A noticeable decrease in NOx concentrations has been reported due to the lockdown measures implemented to curb the spread of Corona Virus Disease 2019 (COVID-19). However, questions remain, regarding the nonlinear relationship between NOx and NO3−. Here, we collected PM2.5 samples in two periods, before and during the lockdown of COVID-19 in Shanghai. Dual isotopes (δ18O-NO3− and δ15N-NO3−) of NO3− were measured to investigate the formation pathways and potential sources of NO3−. The results showed that the concentration of NO3− decreased significantly during the lockdown period compared to the period before the lockdown. Additionally, the hydroxyl pathway was the dominant contributor to NO3− production during the lockdown period, while N2O5 hydrolyses dominated the formation of NO3− before the lockdown. This change is largely attributable to alterations in the oxidative potential of the environment. In comparison to the period preceding the lockdown, the relative contributions of each NOx source remained largely unchanged throughout the lockdown periods. Nevertheless, the concentration of NO3− contributed by each NOx source exhibited a notable decline, particularly the mobile sources and coal combustion. Furthermore, the reduction extent of NO3− due to the lockdown period was also greater than the reduction during the Clean Air Actions (2013–2017). Our findings provide evidence that the COVID-19 lockdown led to a decrease in NO3− concentration due to changes in the formation pathway and reductions in NOx emissions from various sources.

Preparation and Properties of 3D Spherical Bi2S3/Bi2O2CO3 Photocatalytic Materials Self‐Assembled by 2D Nanosheets

ABSTRACTThe micro‐morphology of photocatalytic materials has a great influence on their photocatalytic performance. Quantum dots can provide the plasmon resonance effect and broaden the wavelength range of light absorption. In this study, a kind of 3D spherical flower‐like structure was constructed by self‐assembly of 2D nanosheets, the Bi2S3 particles with 5 ± 1 nm diameter were modified on the surfaces of Bi2O2CO3 nanosheets to prepare the Bi2S3/Bi2O2CO3 composite. The energy level difference (0.45 eV) between the conduction bands (CB) of Bi2S3 and Bi2O2CO3 led to which the e− was transferred to CB of Bi2O2CO3. The energy level difference (0.83 eV) between the CB of Bi2O2CO3 and the valence band (VB) of Bi2S3 was much smaller than the band gap (1.28 eV) of Bi2S3, and it led to which the electrons on the CB of Bi2O2CO3 were recombined with the holes on the VB of Bi2S3. A kind of innovative type heterojunction was constructed between Bi2S3 and Bi2O2CO3, which encouraged the photogenerated h+ and ·OH to be located on the VB of Bi2O2CO3 with the strongest oxidation potential, the prepared material showed excellent performance for the photodegradation of RhB, and the active groups were also controlled in the photocatalysis process.

Study of quinine hydrochloride detection using boron-doped diamond electrodes

This study investigates the electrochemical properties of quinine hydrochloride (QH) using boron-doped diamond (BDD) electrodes. The redox behavior of QH was analyzed and compared in phosphate buffer solution (PBS) and potassium perchlorate (KClO4) electrolyte, observing an increase in current response with hydrogen-terminated BDD (H-BDD) electrodes. A cyclic voltammogram of QH in 0.1 M PBS and 0.1 M KClO4 shows a reduction peak at −1.14 V (vs. Ag/AgCl). The scan rate dependence was examined to understand the reduction mechanism involving two electrons. A linear calibration curve was noted from 2 μM to 25 μM range (R2 = 0.99) with detection limits of 0.18 μM in PBS and 0.16 μM in KClO4. The BDD electrodes demonstrated good selectivity in tonic water with sharp oxidation potentials for QH, confirming their stability for QH detection.

A General Radical Functionalization of Quinoxalin-2(1H)-ones via a Donor-Acceptor Inversion Strategy.

The radical donor-acceptor inversion strategy represents a highly promising approach in the field of radical chemistry. The present study initially describes a metal-free, versatile, and modular approach for the radical functionalization of quinoxalin-2(1H)-ones via a strategy of radical donor-acceptor inversion under simple reaction conditions. More than 66 examples were provided in moderate yields. The mechanistic study has confirmed that the driving force behind this radical reaction is the in situ formation of a salt through the interaction between quinoxalin-2(1H)-ones and acid/HFIP, which exhibits potent oxidation properties. Additionally, it has been observed that the evident hydrogen bonding between quinoxalin-2(1H)-ones and HFIP can effectively mitigate the oxidation potential.

Enhanced Photocatalytic Activity of Direct Z‐Scheme K4Nb6O17/Carbon‐Rich Melon Heterostructures

AbstractMelon (also known as graphitic carbon nitride, g‐C3N4) holds promise for photocatalysis, but challenges such as severe charge recombination, low oxidation potential, and sluggish exciton dissociation hinder its performance. Herein, a series of carbon‐rich, melon‐based photocatalysts are synthesized via one‐pot, temperature‐induced condensation of urea with the addition of a trace amount of citric acid. The addition of citric acid enhances crystallinity, extends melon chains, increases the C/N ratio, and improves π–π layer stacking of heptazine units, thereby enhancing charge transport properties and visible‐light harvesting capacity. These carbon nitride samples are then coupled with molten salt synthesized K4Nb6O17 crystals by a straightforward self‐assembly method to construct 2D/2D heterostructure photocatalysts. Z‐scheme electron transfer from K4Nb6O17 to the melon samples is established based on their work functions and band edge positions. This efficient charge transfer in the Z‐scheme heterostructure facilitates the spatial separation of charge carriers, resulting in a nearly fivefold enhancement in photocatalytic performance compared to the individual constituents.

Synergistic degradation of p-nitrophenol using peroxymonosulfate activated with a bimetallic Mn3O4–Cu2O catalyst: Investigation of strong interactions between metal oxides

The use of efficient, eco-friendly catalysts is essential for activating peroxymonosulfate (PMS) to degrade organic contaminants in aqueous media. In this study, we developed a novel approach to fabricating bimetallic MnCu catalysts (Mn:Cu molar ratios: 10:1, 5:1, 3:1, and 2:1) comprising tetragonal Mn3O4 and cubic Cu2O. MnCu-5:1 exhibited superior catalytic activity for the degradation of p-nitrophenol (PNP) using PMS because of the synergistic interplay between Mn and Cu. Experimental and density functional theory (DFT) calculation data revealed that the mixed valence states and strong interactions between Mn and Cu in the MnCu-5:1 system increased the electron transfer efficiency and promoted electron transfer to PMS. The results of quenching experiments elucidated a primary radical mechanism and minor nonradical pathway for the PNP degradation over the MnCu-5:1/PMS system. DFT calculations confirmed a relatively high adsorption energy of the Mn3O4–Cu2O (MnCu) composite, indicating enhanced catalytic performance. The superior reactivity of the composite was verified by analyzing its density of states and electrostatic difference potential. Our findings offer fresh perspectives for harnessing the synergistic potential of less toxic mixed metal oxides for controlling catalytic properties and help achieve a better understanding of the activation mechanism for contaminant degradation over MnCu catalysts.