Oxidant Research Articles

Effect of bioactive compounds from culinary herbs against cholesterol thermo-oxidation in omelets during home cooking processes

The prooxidant environment created during cooking induces cholesterol oxidation, compromising the safety of homemade foods. Thus, this study investigated the potential of basil and oregano as anti-cholesterol oxidation agents during omelet preparation by air frying and oil-free pan frying. Cooking induced cholesterol oxidation, as the content of cholesterol oxidation products (COPs) in control samples was higher after air frying (821.05 ± 13.77 μg/g) and pan frying (311.07 ± 13.84 μg/g) compared to the raw samples (40.69 ± 2.26 μg/g). However, both herbs effectively mitigated cholesterol oxide formation. While oregano yielded better results during air frying (from 152.04 ± 5.85 to 377.8 ± 6.4 μg/g of total COPs), similar effects were observed for both herbs in pan-fried samples (from 72.8 ± 7.7 to 272.1 ± 3.8 μg/g). UHPLC-ESI-MS analyses revealed the presence of antioxidants in herbs, primarily phenolic acids like p-Coumaric, vanillic, caffeic, and rosmarinic acids, but the impact of cooking on herbs’ antioxidant constituents was also demonstrated since some of them were no longer detected in cooked omelets containing the herbs. Despite it, this study suggests the use of basil and oregano as a viable method to minimize the formation and, consequent, consumption of cholesterol oxidation products.

Synthesis of morphology-controlled ternary nanocomposite with the aid of surfactant (CATAB) as structure-directing agent for catalytic oxidation of organic azo dye

ABSTRACT A novel synthesis approach was applied to deposit tri-metal oxide nanocomposite, AL₂O₃/TiO₂/ZnO, onto surfactant template in an attempt to control the morphology and reduce the aggregation . Consequently, increases the surface area available for catalytic activity. Different samples were prepared by varying the amount of CTAB as a structure-directing agent. Samples were characterized by SEM, XRD, UV-Vis, DLS, TGA, FTIR, and nitrogen adsorption. The nanocomposites were tested for the catalytic oxidation of Congo red (CR). Calcination resulted in higher activity as a result of removing the template and thus leaving empty pores with higher surface area. Before calcination, the amount of CATAB added inversely affected both available surface area and activity. The maximum oxidation efficiency was 92%. TOC analysis confirmed mineralization of CR by 82% drop. After four successive cycles, only 3% reduction in catalysis activity was observed. Overall, this proposed method is very promising in controlling morphology, structural properties, and catalytic activity of catalyst.

Design of a non-oxidative adhesive dopamine-grafted hyaluronic acid/NOCC hydrogel for enhanced cell spheroid formation and soft tissue regeneration

Tissue adhesive hydrogels from dopamine represent a compelling material with diverse applications across engineering and medical fields. Although numerous designed adhesive hydrogels have been developed, significant limitations have arisen from the reliance on hydrogen peroxide as an activating agent for crosslinking hydrogels. To address this, our study investigates an innovative approach to create an adhesive and biocompatible hydrogel from dopamine conjugated-hyaluronic acid (Da-HA) and N, O-Carboxymethyl Chitosan (NOCC) without the need for oxidative agent treatment for use in biomedical engineering application. The reactions were performed under mild alkaline conditions, vigorous stirring, and curing, resulting in DHC hydrogels. Proper modification and reactions in the hydrogel matrix were confirmed by NMR spectroscopy and Fourier transform infrared spectroscopy (FTIR). The gelling and tissue adhesive properties of the produced DHC hydrogel are proportional to the Da-HA content in the hydrogel. Scanning electron microscopy revealed changes in pore walls among samples and pore diameters ranging from 100 to 300 nm. Rheological analysis demonstrated a high visco-elastic material and self-healing properties. Importantly, the growth of L929 cell spheroids was noted upon their cultivation atop the designed hydrogel. The material holds significant promise for 3D printing and cell encapsulation therapies, as well as in situ tissue repair, particularly for mechanically dynamic tissues like the dermis.

Enhancing photocatalytic H2 evolution of Cd0.5Zn0.5S with the synergism of amorphous CoS cocatalysts and surface S2− adsorption

Designing surface phase is an efficient strategy to facilitate charge separation and photocatalytic H2-evolution performance. In this work, CoS cocatalysts were intimately anchored on Cd0.5Zn0.5S (denoted as CZS) photocatalyst via in-situ precipitate transformation in S2−/SO32− solution with cobaltous phosphate (CoPi) as a precursor, meanwhile, S2− ions were adsorbed on the CZS to form a sulfur-rich surface (denoted as CZS-S). The photocatalytic H2-evolution rate of CoS/CZS-S is 2.02 mmol·g−1·h−1 in 0.1 M Na2S/Na2SO3 sacrificial agent system. In addition, CoS/CZS-S exhibits excellent stability in both Na2S/Na2SO3 and lactic acid system. The theoretical calculations (DFT) and experimental results reveal that amorphous CoS can work as a highly effective cocatalyst for H2 evolution reaction and the intimate contact between CZS and CoS facilitates the photoelectrons transfer from CZS to CoS. The adsorbed S2− ions mainly work as effective hole acceptors. As a result of the synergism of CoS and adsorbed S2− ions, the boosted separation and immigration of photoelectrons and photoholes and high photocatalytic H2-evolution performance of CoS/CZS-S are realized. The present work highlights simultaneous reinforcing reduction and oxidation half-reaction dynamics via a facile and economic surface strategy to achieve efficient solar H2-evolution from H2O splitting.

A novel pillar-layered MOF with urea linkers as a capable catalyst for synthesis of new 1,8-naphthyridines via the anomeric-based oxidation

Metal-based catalysts play an essential role in organic chemistry and the chemical industry. This research designed and successfully synthesized a pillar-layered metal–organic framework (MOF) with the urea linkers, namely Basu-HDI, as a novel and efficient heterogeneous catalyst. Various techniques such as FT-IR, EDX, elemental mapping, SEM, XRD, BET, and TGA/DTA studied its structure and morphology. Then, we investigated the synthesis of new 1,8-naphthyridines utilizing Basu-HDI in mild conditions via a one‐pot, three‐component tandem Knoevenagel/Michael/ cyclization/anomeric-based oxidation reaction. Final products were achieved by anomeric-based oxidation without employing an oxidation agent. Remarkably, this tandem process gave a good range of new 1,8-naphthyridines with high yields in a short reaction time. The pure products were confirmed by FT-IR, 1H NMR, 13C NMR, and mass spectrometry techniques. Moreover, the introduced catalyst showed good efficiency and stability and can be reused four times without significantly reducing efficiency.

Assessment of hydrogen peroxide, persulfate, and peroxymonosulfate as oxidizing agents in electrochemical oxidation of pyridine

The removal of pyridine, a toxic and refractory nitrogen heterocyclic compound from coal chemical wastewater, has been examined using electrochemical oxidation (EO) processes in the presence of hydrogen peroxide (H2O2), persulfate (PDS), and peroxymonosulfate (PMS). Degradation of pyridine was observed in EO/H2O2, EO/PDS, and EO/PMS systems with removal efficiencies of 41.3, 40.6, and 93.5 %, respectively. The energy consumption for the EO/H2O2, EO/PDS, and EO/PMS processes was calculated to be 1.4, 1.3, and 0.56 KWh g−1, respectively. The yield of ClO3- in the EO/PMS system was relatively higher than that in the EO/PDS system. Additionally, the overall concentration of total organic chlorine was lower in the EO/PDS (292.1 mg/L) and EO/PMS (120.1 mg/L) systems when SO4•– radicals were present. The contribution of reactive species were quantified. Specially, in the EO/H2O2 system, the ratio of OH• was 44 %. In the EO/PDS system, the ratios of OH•, SO4•–, and other reactive species were 31 %, 22 %, and 47 %, respectively. In the EO/PMS system, the ratios of OH•, SO4•–, and other reactive species were 18 %, 71 %, and 11 %, respectively. Specifically, in the EO/PMS system, while CCl3 was detected, no other chlorinated organic intermediates were observed. Compared to EO/H2O2 and EO/PDS systems, the EO/PMS system shows better suitability for high Cl– conditions. The pH had a negligible impact on the EO/H2O2 system. Under acid conditions, degradation rate constants for pyridine were highest in the EO/PMS and EO/PDS systems. Notably, the addition of PMS to coal chemical wastewater achieved a 30 % removal of ultraviolet light absorbance at 254 nm (UV254), indicating effective inhibition of trihalomethane formation. This study provides critical insights into optimizing the EO process for the effective removal of refractory pollutants like pyridine from coal chemical wastewater, enhancing environmental safety and treatment efficiency.

Coupling Photocatalytic Hydrogen Production with Key Oxidation Reactions.

Hydrogen represents a clean and sustainable energy source with wide applications in fuel cells and hydrogen energy storage systems. Photocatalytic strategies emerge as a green and promising solution for hydrogen production, which still reveals several critical challenges in enhancing the efficiency and stability and improving the whole value. This review systematically elaborates on various coupling approaches for photocatalytic hydrogen production, aiming to improve both efficiency and value through different oxidation half-reactions. Firstly, the fundamental mechanism is discussed for photocatalytic hydrogen production. Then, the advances, challenges, and opportunities are expanded for the coupling of photocatalytic hydrogen production, which focuses on the integration of value-added reactions including O2 production, H2O2 production, biomass conversion, alcohol oxidation, and pollutants treatment. Finally, the challenges and outlook of photocatalytic H2 production technology are analyzed from the aspects of coupling hydrogen production value, photocatalyst design and reaction system construction. This work presents a holistic view of the field, emphasizing the synergistic benefits of coupled reactions and their practical application potential, rather than focusing on catalysts or single reaction systems. This review provides valuable references for the development and application of photocatalytic hydrogen production in energy conversion and environmental conservation through sustainable, eco-friendly and economic pathways.

Field and laboratory perspectives on fentanyl and carfentanil decontamination

Abuse of the highly toxic compound fentanyl and its analogues is increasing, raising serious public health concerns due to their potency and availability. Therefore, there is a need for decontamination methodologies to safely remove fentanyl to avoid harmful exposure. In this study, the efficacy of commercial and in-house synthesized decontamination agents (Dahlgren Decon, RSDL (Reactive Skin Decontamination Lotion), FAST-ACT (First applied sorbent treatment against chemical threats), GDS2000, alldecont MED, bleach, Domestos Spray Bleach, Effekt Klor, MgO, TiO2-nanodiamond, and CeO2) were evaluated for the degradation of fentanyl and carfentanil under controlled laboratory conditions and on wooden floor surfaces. Liquid chromatography/mass spectrometry analysis showed that oxidative decontamination agents were the most effective, with N-oxides identified as major degradation products. The physiological effects of these N-oxides were also investigated regarding their ability to activate the µ-opioid receptor and their metabolism in human liver microsomes. The results provide empirical evidence that complements prior research findings on the degradation of fentanyl and carfentanil using a variety of decontamination agents.

Sulfuric Acid Leaching Recovery of Rare Earth Elements from Wizów’s Phosphogypsum in Poland

Rare earth elements (REEs) are considered vital raw materials for the economy and are on the European Union’s list of critical raw materials (CRMs). Europe is mainly dependent on REE imports. This dependence could be reduced if locally available primary or secondary resources would be processed. In Poland, there are, for instance, over 5 million metric tons of phosphogypsum (PG), a fine powdery byproduct from the fertilizer industry, available near the former Wizów Chemical Plant near Bolesławiec. This material that is considered a waste in Poland contains significant amounts of REEs that could theoretically be recovered and contribute to Europe’s economy. This work is the first systematic analysis of REE leaching studies with sulfuric acid and PG from Wizów. Process parameters such as temperature, particle size, concentration of the leaching solution, and the addition of oxidant and reductant agents were tested to determine the most efficient process. Ultimately, a leaching efficiency of 99% was obtained. Lanthanum exhibited the highest leaching efficiency at almost 100%, followed by Yttrium, Neodymium, Terbium, and Dysprosium. The results of the laboratory experiments are promising and suggest that larger pilot or commercial experiments can be performed next.

Photocatalytic Hydrogenation of Alkenes Using Water as Both the Reductant and the Proton Source.

Utilization of clean and low-cost water as the reductant to enable hydrogenation of alkenes is highly attractive in green chemistry. However, this research subject is considerably challenging due to the sluggish kinetics of the water oxidation half-reaction. It is also very difficult to avoid the undesired oxidation of alkenes because that this oxidation is far easier to occur than the desired oxidation of water from thermodynamic standpoint. Herein, this challenge is overcome by applying a cooperative catalysis where HCl is used as the cocatalyst to accelerate Pt/g-C3N4-catalyzed water oxidation and suppress the undesired oxidation of the alkene. This provides an example for using water as the reductant and the proton source to enable the photocatalytic hydrogenation of alkenes. The present method exhibits broad substrate applicability, and allows various arylethenes and aliphatic alkenes to undergo the hydrogenation smoothly.

The Combined Effect of the Oxidizing Agent and its Concentration on the Oxidative Coupling of Methane

AbstractThe combined use of O2 and CO2 as oxidizing agents in the oxidative coupling of methane (OCM) has been assessed over two representative OCM catalysts, i. e., La−Sr/CaO and NaMnW/SiO2, under a wide range of inlet O2 and CO2 concentrations. The overall impact of CO2 was found to depend on the operating conditions and the catalyst used. At O2‐rich conditions, a negative effect of CO2 was observed on C2 selectivity. At O2‐lean conditions, a positive effect of CO2 on both catalysts was observed, likely originating from an enhanced dehydrogenation of C2H6 to C2H4 and limited deep oxidation of the involving hydrocarbons and reaction intermediates. The behavior induced by CO2 is attributed to its mild oxidizing ability and interactions with the catalysts. The enhanced dehydrogenation of C2H6 was observed and confirmed by specific tests with a CO2 and C2H6 feed. Well‐controlled CO2 addition improved the value of the OCM product mixture, mainly due to a 9 % increase in C2H4 and a 19 % increase in CO selectivity, resulting in a 25 % reduction of CO2 at the outlet over the La−Sr/CaO catalyst. These findings provide new insight into the CO2 effect on OCM and the data to translate this research into OCM process alternatives.

Triflate Salts as Alternative Non-Chlorinated Oxidants for the Oxidative Chemical Vapor Deposition and Electronic Engineering of Conjugated Polymers.

Oxidative chemical vapor deposition (oCVD) stands as an attractive approach for the synthesis, engineering, and integration of conjugated polymers for advanced electronic and optoelectronic applications. In oCVD, the oxidant significantly influences the conformational and optoelectronic properties of the resulting conjugated polymer thin films. In this work, triflate salts of iron(III) and copper(II) (Fe(OTf)3 and Cu(OTf)2, respectively) are investigated for the first time as suitable alternative oxidants to the widely used iron(III) chloride (FeCl3) for the oCVD of conjugated polymers. Structural and compositional characterizations of the resulting thin films evidenced the successful polymerization of cobalt(II) 5,15-diphenyl porphyrin using either Fe(OTf)3 or Cu(OTf)2. Along with an intermolecular dehydrogenative C-C coupling reaction, the occurrence of side reactions, such as the inclusion of -CF3 groups and demetalation and subsequent insertion of copper(II) in the porphyrin macrocycle when using Cu(OTf)2, were evidenced. Interestingly, the inclusion of -CF3 groups into the polymer backbone when using triflate salts results in a deepening of the frontier energy levels, while the insertion of copper(II) contributes to a reduction in the band gap energy. This work demonstrates that the careful selection of the oxidant agent in oCVD enables fine-tuning the optoelectronic properties of conjugated polymers to suit specific application requirements.

An electrocatalytic iodine oxidations-based configuration for hydrogen and I2/I3− co-productions driven by the Zn-air/iodine battery

Electrochemical water splitting and energy storage are key for a sustainable energy future, despite the challenges related to undesirable overpotentials and high voltage requirements. Herein, we introduce a synergistic approach between a low overpotential hydrogen evolution reaction (HER) and a low voltage zinc-air/iodine battery (ZAIB) by coupling with iodide oxidation half reactions. By developing a Pt/Co3O4 electrocatalyst in two steps and with under 2% Pt loading, we achieve an unprecedented low full cell potential for hydrogen generation at 0.574 V, exhibiting an ultra-high reduction of energy consumption of 64.7%. The Pt/Co3O4 electrode also enables ZAIB to record a power density of 154 mW cm−2 at an ultra-low charging potential of 1.68 V. Mechanistic studies and DFT calculations of the novel electrode confirm an electron rich Pt-Co interface and favorable Pt-I interactions, facilitating both HER and IOR reactions. Our design provides critical technology for potential large-scale renewable energy projects.

Immunofluorescent detection of protein CoAlation in mammalian cells under oxidative stress.

Previously, we reported the generation and characterisation of highly specific anti-CoA monoclonal antibodies capable of recognizing CoA in various immunological assays. Utilizing these antibodies in conjunction with mass spectrometry, we identified a wide array of cellular proteins modified by CoA in bacteria and mammalian cells. Furthermore, our findings demonstrated that such modifications could be induced by oxidative or metabolic stress. This study advances the utility of anti-CoA monoclonal antibodies in analysing protein CoAlation, highlighting their effectiveness in immunofluorescent assay. Our data corroborates a significant increase in cellular protein CoAlation induced by oxidative agents. Additionally, we observed that hydrogen-peroxide induced protein CoAlation is predominantly associated with mitochondrial proteins.

Bioactive matrix scaffold of oxidized sacchachitin via green catalyst of siliacat tempo for enhancing bone regeneration

Bone regeneration remains a critical challenge in orthopedic medicine. Extracellular matrix proteins play important roles in bionic mineralization and osteogenesis. Sacchachitin nanofibers (SCNFs) oxidized via TEMPO have shown great potential as biomaterial scaffolds due to the introduction of carboxylic groups that mimic the natural extracellular matrix. However, TEMPO is harmful to the environment, which calls for greener and sustainable alternatives. Therefore, this study explored the green fabrication of oxidized-SCNFs through SiliaCat-TEMPO (STEMPO) as a renewable catalyst with various amount of oxidation agents to evaluate their bone regeneration ability. We developed an optimal STEMPO oxidation process, enabling efficient removal of most STEMPO particles through centrifugation with minimal residue. The oxidation efficiency of recovered STEMPO particles remained comparable to fresh ones. STEMPO-oxidized SCNFs, oxidized at increasing NaClO levels, showed an increase in carboxylate content, from 0.1360 mmol/g to 3.2415 mmol/g. Additionally, STEMPO-oxidized SCNFs exhibited excellent biocompatibility with MC3T3-E1 osteoblastic cells, facilitating calcium precipitation, cell migration, and osteogenic differentiation. Mixed composites of β-tricalcium phosphate (BCP) and STEMPO-oxidized SCNFs with higher oxidation levels further enhanced osteogenic differentiation. In vivo studies using a rat femur defect model showed that SCNFs at the highest oxidation level (ST100SC) significantly promoted bone regeneration to full recovery, achieving a bone volume to total tissue volume (BV/TV) ratio of 75.6 %, compared to 48.3 % in the control. These results demonstrated that STEMPO-oxidized SCNFs with higher oxidation levels can be used as a bioactive matrix scaffold to achieve full recovery of bone regeneration.

The SUMO gene MrSmt3 is involved in SUMOylation, conidiation and stress response in Metarhizium robertsii.

Smt3, as a small ubiquitin-like modifier (SUMO), play an essential role in the regulation of protein SUMOylation, and thus this process can affect various important biological functions. Here, we investigated the roles of MrSmt3 (yeast SUMO/Smt3 homologs) in the entomopathogenic fungus Metarhizium robertsii. Our results of subcellular localization assays demonstrated that MrSmt3 was present in the cytoplasm and nucleus, whereas MrSmt3 was largely localized in the nucleus during oxidative stress. Importantly, disruption of MrSmt3 significantly decreased the level of protein SUMOylation under heat stress. Deletion of MrSmt3 led to a significant decrease in conidial production, and increased sensitivity to various stresses, including heat, oxidative, and cell wall-disturbing agents. However, bioassays of direct injection and topical inoculation demonstrated that deletion of MrSmt3 did not affect fungal virulence. Furthermore, RNA-seq analysis identified 1,484 differentially expressed genes (DEGs) of the WT and ΔMrSmt3 during conidiation, including 971 down-regulated DEGs and 513 up-regulated DEGs, and further analysis showed that the expression level of several classical conidiation-associated genes, such as transcription factor AbaA (MAA_00694), transcription factor bZIP (MAA_00888) and transcription factor Ste12 (MAA_10450), was down-regulated in the ΔMrSmt3 mutant. Specifically, the major downregulated DEGs were mainly associated with a variety of metabolic regulatory processes including metabolic process, organic substance metabolic process and primary metabolic process. Collectively, our findings highlight the important roles of the SUMO gene MrSmt3 in modulating SUMOylation, conidiation and stress response in M. robertsii.

The mechanisms of the copper-carbonate catalyzed oxygen evolution reaction

Copper carbonate/bicarbonate complexes are good catalysts of the oxygen evolution reaction, OER. Previous electro-catalytic studies suggested that at pH 10.8 the active intermediate is a CuIII complex whereas at pH 6.8 the active intermediate is a CuIV complex. Previous pulse-radiolysis studies indicated that CuIII complexes are the active intermediates at both pHs. To solve the source of this discrepancy, the copper carbonate/bicarbonate catalyzed OER using peroxy-mono-sulfate as the oxidant was studied. In this system CuIV complexes are the active intermediates. The result points out that two electron oxidants yield CuIV complexes and one electron oxidants yield CuIII complexes; both types of complexes are water oxidation agents. Electrochemical processes might proceed via both mechanisms as the anode can act as a two-electron acceptor. Thus, pulse-radiolysis does not always yield the same intermediates as electrochemistry.

Regioselective Oxidation of Tetrahydronaphthalenes to α-Tetralone Derivatives Using DDQ as Oxidizing Agent: Synthesis and Evaluation of Antibacterial and Antifungal Activities.

An easy and efficient approach for the synthesis of highly regioselective functionalized dihydronaphthalen-1(2H)-one family of α-tetralones from functionalized tetralone precursors which derived from Morita-Baylis-Hillman (MBH) adducts as starting substrates has been developed. The target dihydronaphthalen-1(2H)-ones are obtained through the oxidation of tetrahydronaphthalenes (THN) using DDQ as the oxidizing agent, conducted in aqueous acetic acid at reflux conditions. The yields obtained ranged from 90 to 98%. The resulting dihydronaphthalen-1(2H)-ones were evaluated for their in vitro antibacterial activity against nine Gram-positive and six Gram-negative strains. Additionally, their antifungal properties were assessed against three fungal pathogens by using the microdilution method and Biolog Phenotype Microarrays technology. Remarkably, the synthesized dihydronaphthalen-1(2H)-ones exhibited good antibacterial activity when compared to reference drugs such as vancomycin and ampicillin. Similarly, their antifungal activity is comparable to the effectiveness of the reference drugs cycloheximide and fluconazole.

Inhibitory Effects of Polyphenols from Equisetum ramosissimum and Moringa peregrina Extracts on Staphylococcus aureus, Collagenase, and Tyrosinase Enzymes: In vitro Studies

Background: Skin problems caused by oxidative stress lead to the activation of collagenase and tyrosinase enzymes, contributing to skin aging, discoloration, and infections. Equisetum ramosissimum and Moringa peregrina were assessed for their potential uses in treating various skin conditions. Objective: The present research aimed to investigate the positive effects of polyphenols in Equisetum ramosissimum and Moringa peregrina extracts as potential cosmetic products for the treatment of different skin conditions. Methods: Total phenolic and flavonoid contents, antioxidants, and anti-collagenase and anti-tyrosinase activities of plant extract mixtures (PEM) at different ratios of (M. peregrina: E. ramosissimum) were determined using standard procedures. Inhibitory effects of PEM against acne-causing Staphylococcus aureus (ATCC 29213) were evaluated using the diameter (cm) of the inhibition zone method. A cream formulation containing PEM was developed and characterized for stability and potential skin irritation in rats using standard procedures. Results: The PEM at a ratio of (2:1) showed the highest total phenolic and flavonoid content (150.15 ± 2.8 mg/g, equivalent to gallic acid, and 41.5 ± 1.2 mg/g, equivalent to quercetin, respectively). Antioxidant activities for PEM (2:1) were also optimal, as determined by the DPPH and ABTS methods (IC50 = 7.06 ± 0.12 µg/mL and 53.29 ± 3.3 µg/mL, respectively). Furthermore, PEM (2:1) exhibited superior inhibitory activities against collagenase and tyrosinase enzymes (IC50 = 32.4 ± 1.19 µg/mL and 8.4 ± 1.19 µg/mL, respectively). Antimicrobial activity of PEM (2:1) tested on S. aureus showed the largest zone of growth inhibition (2.8 cm) at a concentration of 60 mg/mL. Studies on the PEM (2:1) cream formulation revealed that it remained stable under room conditions. Skin irritation tests on rats showed no signs of oedema or erythema after treatment. Conclusion: The PEM with a ratio of (2:1) demonstrated optimal activity as an oxidative stress-neutralizing agent, inhibitor of enzymes responsible for skin aging and hyperpigmentation, and antibacterial agent. The cream formulation containing PEM exhibited physical stability and no detectable risk of skin irritation throughout the research procedures.

Monitoring Hot Holes in Plasmonic Catalysis on Silver Nanoparticles by Using an Ion Label.

Energetic carriers generated by localized surface plasmon resonance (LSPR) provide an efficient way to drive chemical reactions. However, their dynamics and impact on surface reactions remain unknown due to the challenge in observing hot holes. This makes it difficult to correlate the reduction and oxidation half-reactions involving hot electrons and holes, respectively. Here we detect hot holes in their chemical form, Ag(I), on a Ag surface using surface-enhanced Raman scattering (SERS) of SO32- as a hole-specific label. It allows us to determine the dynamic correlations of hot electrons and holes. We find that the equilibrium of holes is the key factor of the surface chemistry, and the wavelength-dependent plasmonic chemical anode refilling (PCAR) effect plays an important role, in addition to the LSPR, in promoting the electron transfer. This method paves the way for visualizing hot holes with nanoscale spatial resolution toward the rational design of a plasmonic catalytic platform.