Superoxide Research Articles

Constructing homo/hetero-nuclear carbon and oxygen atoms co-doped graphitic carbon nitride assisted by ionic liquid for photothermal synergistic catalytic oxidation of cyclohexane

The adoption of photothermal synergistic catalysis for cyclohexane oxidation can balance the advantages of high conversion of thermal catalysis and high selectivity of photocatalytic technology to achieve better catalytic performance. Here, we prepared functional carbon nitride (BCA-CN) by self-assembly strategy of ionic liquid [Bmim]CA (1-Butyl-3-methylimidazole citrate) with melamine and cyanuric acid utilizing abundant elements and anionic/cationic hydrogen bonding interactions. The introduction of [Bmim]CA embeds C-C (carbon and carbon band) and C-O-C (ether bond) structures into graphitic carbon nitride (g-C3N4) framework, significantly improving light absorption capacity and migration of photo generated charge carriers. Compared to g-C3N4, both BCA-CN increases cyclohexane conversion and KA oil (the mixture of cyclohexanol and cyclohexanone) selectivity by 1.3 times under photothermal catalysis. The surface reactions are facilitated by changing adsorption sites of cyclohexane to increase adsorption energy and obtaining more hydroxyl radicals and superoxide radicals. Furthermore, the enhanced selectivity is attributed to the difficulty in generating cyclohexanone radicals. This work offers the reference scheme for the development of efficient photothermal catalysts in the selective oxidation of cyclohexane.

Sulfur vacancies form charge transport channels on the S-type heterojunction engineered interface to enhance photocatalytic performance

This article presents the synthesis of an S-type heterojunction photocatalyst through a straightforward hydrothermal process, which involves the combination of FeWO4 with Zn0.5Cd0.5S containing sulfur vacancies (Zn0.5Cd0.5Ssv). The study delves into the intrinsic role of sulfur vacancies in enhancing the photocatalytic performance of the S-type heterojunction. The creation of sulfur vacancies effectively controls charge separation and triggers a rapid charge transfer pathway at the heterojunction, improving light absorption and permitting the formation of more photoinduced charges. The material demonstrates an impressive degradation efficiency, capable of breaking down 79.38% of IOH within just 40 minutes. It exhibits robust catalytic activity under both mildly acidic and mildly basic conditions, showing notable resistance to various anions and cations present in water, as well as a significant tolerance to high concentrations of humic acid. Further, trapping experiments reveal that hydroxyl radicals (•OH) and superoxide radicals (•O2⁻) are the predominant reactive species driving the photocatalytic process. This research sheds new light on the modulation of photogenerated charge carrier dynamics at the heterointerface, offering valuable guidance for the development of high-performance S-type photocatalysts.

Preparation of Magnetic Fe‐Decorated Carbon Nanosheets From Waste Facemasks for Quantitative Detection of Flavonoids

ABSTRACTMany studies relating to the preparation of magnetic composites from various raw materials have been reported. However, for the first time, the magnetic Fe‐decorated carbon nanosheets (FeCNs) were prepared using waste facemasks with iron‐containing nose strip as both carbon source and iron source. The uniform decoration of Fe3O4 nanoparticles not only endows carbon matrix with magnetic separation property but also enriches the lamellar structure to furnish more catalytically active sites. The as‐prepared FeCNs nanozymes behave optimal peroxidase‐like activity under pH of 4 and temperature of 50°C, excellent reusability, and substrate affinity. Based on FeCNs, a convenient colorimetric strategy was successfully constructed for flavonoid detection in simulated and real samples. Experimental and theoretical results show that hydroxyl radicals (•OH) and superoxide radical (•O2−) are the major active species in the reactions that are catalyzed by FeCNs in the presence of H2O2. And the generation of these radicals can be attributed to the electron transfer between Fe2+/Fe3+ pairs and H2O2 molecules. This work provides a new way for preparing magnetic carbon‐based nanozymes and realizes the resource utilization of waste facemasks.

Investigating the photocatalytic reduction of U(VI) over a single-atom Fe complex catalyst

Fabrication of effective photocatalyst for the U(VI) reduction is a promising approach to disposing the great challenges posed by rising the rapid development of nuclear energy. Herein, it rationally designed a single-atom Fe anchored g-C3N4 support (Fe-g-C3N4, Fe-N4 moiety), showing the ultrahigh photocatalytic performance towards over wide pH range of 3.0–8.0, outer-performing pristine g-C3N4 by 82 times. Combination with X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectroscopy, the highly photoreduction of U(VI) could be attributed to the highly activity of g-C3N4 and Fe2+. According to quenching experiments and EPR spectra, it is demonstrated that the superoxide (·O2–) radicals played an important role in the photoreduction of U(VI) on Fe-g-C3N4 rather than ·OH and 1O2 species. These findings are crucial for the actual application of single-atom photocatalyst in environmental remediation.

Pyrazine-based supramolecular photosensitizing assemblies as type I photosensitizers for high-efficiency photooxidation reactions

Donor-acceptor thermally activated delayed fluorescent (TADF) materials have been widely used in photocatalytic reactions as organic photosensitizers. However, the construction of TADF photosensitizers via a supramolecular self-assembly approach with the regulation of reactive oxygen species (ROS) is still a big challenge. In this study, a TADF molecule 4,4'-(6-(pyridin-4-yl)quinoxaline-2,3-diyl)bis(N,N-diphenylaniline) (TPA-PQ) by incorporating triphenylamine (TPA) act as donor and 6-(pyridin-4-yl)quinoxaline (PQ) act as an acceptor was designed and synthesized, which exhibited excellent TADF property and strong intramolecular charge transfer. Meanwhile, the TPA-PQ can not only self-assemble to form nanofiber structure in mixed solvent of H2O and THF, but also can be used as a type I photosensitizer to selectively produce superoxide anion radicals (O2•–). More interestingly, the ROS generated from TPA-PQ can be used as photocatalysts for the oxidative hydroxylation of arylboronic acids and aerobic cross dehydrogenation coupling (CDC) reactions with high yields of 92 % and 88 %, respectively. This study presents an innovative and eco-friendly approach to utilize TADF supramolecular structures for the purpose of conducting photocatalyzed organic reactions.

Antioxidant activity of Zuccagnia-type propolis: A combined approach based on LC-HRMS analysis of bioanalytical-guided fractions and computational investigation

This study reports a combined approach to assess the antioxidant activity of Zuccagnia-type propolis. Fractions exhibiting the highest antioxidant activities evidenced by DPPH, a β-carotene bleaching and superoxide radical scavenging activity-non-enzymatic assays, were processed by LC-HRMS/MS to characterize the relevant chemical compounds. A computational protocol based on the DFT calculations was used to rationalize the main outcomes. Among the 28 identified flavonoids, caffeic acids derivatives were in the fraction exhibiting the highest antioxidant activity, with 1-methyl-3-(4′-hydroxyphenyl)-propyl caffeic acid ester and 1-methyl-3-(3′,4′-dihydroxyphenyl)-propyl caffeic acid ester as major components. Results clearly showed roles of specific chemical motifs, which can be supported by the computational analysis.This is the first report ascribing the antioxidant ability of Zuccagnia-type propolis to its content in specific caffeic acid derivatives, a potential source of radical scavenging phytochemicals. The proposed protocol can be extended to the study of other plant-products to address the most interesting bioactive compounds.

Constructing p-n heterojunctions of Cl-Cu2O and PANI on three-dimensional nanofiber networks for enhanced photocatalytic degradation of oxytetracycline

A p-n heterojunction was constructed on a bacterial cellulose (BC) film by combining n-type semiconductor chlorine-doped Cu2O (Cl-Cu2O) and p-type semiconductor polyaniline (PANI), creating a ternary composite flexible film of Cl-Cu2O/PANI/BC. The chemical structure, microscopic morphology, and photoelectrochemical properties of Cl-Cu2O/PANI/BC were characterized and analyzed. Compared with pure Cl-Cu2O, the Cl-Cu2O/PANI/BC composite flexible film exhibited a broader response range to visible and near-infrared light, higher carrier concentration, lower impedance value, and substantial reduction in the recombination probability of photogenerated carriers. The process conditions for the photocatalytic degradation of oxytetracycline (OTC) were optimized using the response surface method, and the degradation rate of OTC caused by the Cl-Cu2O/PANI/BC was 96.3 %. In the degradation process of OTC, superoxide radical is the main active species. It was found that OTC molecules degraded via demethylation, secondary alcohol oxidation, decarboxylation, and deamination reactions, finally being degraded into H2O, CO2, and other small organic molecules. Thirteen major intermediates and possible degradation pathways were speculated. The photocatalytic performance of the Cl-Cu2O/PANI/BC was improved owing to the successful construction of the p-n heterojunction. The built-in electric field generated at the interface between the two semiconductors promoted the diffusion of photogenerated holes from the n-type Cl-Cu2O particles to the PANI coating layer on the BC chain, whereas the photogenerated electrons from PANI diffused toward Cl-Cu2O, accelerating the separation efficiency of photoinduced electrons and holes in the two semiconductors and thereby improving the efficiency of photocatalytic degradation. In addition, the three-dimensional network structure of a composite flexible film can help recover the photocatalyst. After performing seven experiments for recovery and reuse, the photocatalytic degradation rate of OTC still remained above 90 %.

Construction of a New 2D Coordination Polymer: Degradation Antibiotic Nitrofurantoin and Magnetism

ABSTRACTThe synthesis of a trinuclear Co(II)‐based coordination polymer (CP), [Co3(HL)2(H2O)6·2.2H2O]n (1), was achieved via a solvothermal method involving CoCl2·6H2O and 3‐(2,4‐dicarboxylphenyl)‐2,6‐dicarboxylpyridine (H3L). The photocatalytic efficiency of the complex was evaluated for the degradation of various antibiotics ornidazole (ODZ), nitrofurantoin (NFT), dinitroaniline (DNZ), and tinidazole (TDZ) in wastewater. Notably, NFT exhibited a remarkable 91.5% degradation within 20 min under optimal conditions. The catalytic performance was influenced by the amount of photocatalyst, NFT concentration, and solution pH, with optimal conditions identified at 6‐mg catalyst dose, 30 mg/L NFT concentration, and pH 7. Trapping experiments highlighted the roles of superoxide and hydroxyl radicals as primary active species in the photocatalytic process. Furthermore, the magnetic behavior is also discussed in detail.

Piezoelectric Bilayer Nickel-Iron Layered Double Hydroxide Nanosheets with Tumor Microenvironment Responsiveness for Intensive Piezocatalytic Therapy.

Piezocatalytic therapy (PCT) based on 2D layered materials has emerged as a promising non-invasive tumor treatment modality, offering superior advantages. However, a systematic investigation of PCT, particularly the mechanisms underlying the reactive oxygen species (ROS) generation by 2D nanomaterials, is still in its infancy. Here, for the first time, biodegradable piezoelectric 2D bilayer nickel-iron layered double hydroxide (NiFe-LDH) nanosheets (thickness of ≈1.86nm) are reported for enhanced PCT and ferroptosis. Under ultrasound irradiation, the piezoelectric semiconducting NiFe-LDH exhibits a remarkable ability to generate superoxide anion radicals, due to the formation of a built-in electric field that facilitates the separation of electrons and holes. Notably, the significant excitonic effect in the ultrathin NiFe-LDH system enables long-lived excited triplet excitons (lifetime of ≈5.04µs) to effectively convert triplet O2 molecules into singlet oxygen. Moreover, NiFe-LDH exhibited tumor microenvironment (TME)-responsive peroxidase (POD)-like and glutathione (GSH)-depleting capabilities, further enhancing oxidative stress in tumor cells and inducing ferroptosis. To the best of knowledge, this is the first report on piezoelectric semiconducting sonosensitizers based on LDHs for PCT and ferroptosis, providing a comprehensive understanding of the piezocatalysis mechanism and valuable references for the application of LDHs and other 2D materials in cancer therapy.

Synthesis and characterization of CuCoFe2O4@GA/AC as a bio-based matrix magnetic nano-heterogeneous photocatalyst for ceftriaxone degradation from aqueous media

Emerging contaminants such as ceftriaxone are a significant issue in the environment. They have led to a series of ecological, environmental, and health issues, and it is urgent to find a green and secure method to remove antibiotics from water effectively. In this research, the CuCoFe2O4@Gum Arabic (GA)/Activated Carbon (AC) as an innovative bio-based matrix magnetic nanocatalyst was synthesized for the efficient degradation of ceftriaxone from aqueous media. The structure of CuCoFe2O4@GA/AC was characterized via FESEM, EDS, Mapping, XRD, FTIR, VSM, and DRS analyses. The structural analysis of the catalyst revealed its synthesis at the nanometer scale (40–50 nm), exhibiting high magnetic strength (Ms: 5.38 emu/g) and favorable optical properties with a bandgap of 3.6 eV. Under optimized conditions, including a pH of 5, 60 min of irradiation time, 0.24 g/L photocatalyst dose, and ceftriaxone concentration of 5 mg/L, the removal efficiency from synthetic and real samples was 94.43% and 62.5%, respectively. The photocatalytic degradation process of ceftriaxone followed pseudo-first-order and Langmuir–Hinshelwood kinetic models. Furthermore, analysis of the process mechanism indicated a prominent role of the superoxide radical. The catalyst had a high recovery capability and chemical stability. The photocatalytic degradation of ceftriaxone by CuCoFe2O4@GA/AC showcased remarkable efficiency, indicating its potential utility in the treatment of wastewater contaminated with antibiotics.

Exploring the therapeutic potential of Modafinil in mitigating renal ischemia-reperfusion injury in rats.

Renal ischemia reperfusion injury (IRI) is a post-ischemic event, which can lead to subsequent acute kidney injury (AKI), transplant failure, renal dysfunction and fibrosis via heightened oxidative stress and production of inflammatory cytokines and chemokines. This study aims to assess the effect of Modafinil, a wake-promoting agent with previously proven anti-inflammatory and anti-oxidative properties, on ameliorating renal IRI. A total of 30 male Wistar rats were divided into five groups: Sham-operated group, ischemia reperfusion (I/R) control group and Modafinil pre-treated groups (at different doses of 50, 100 and 150 mg/kg). IRI was induced by means of bilaterally clamping the renal arteries for 45 min, followed by 24 h of reperfusion. Tissue pathological assessments demonstrated a reduction of glomerular, vascular and interstitial injury at doses of 50 and 100 mg/kg of Modafinil. The biochemical studies showed a significant decrease in tissue pro-inflammatory factors, including tumor necrosis factor alpha (TNF-α), Interleukin-18 (IL-18) and lactate dehydrogenase (LDH). Moreover, an elevation was observed in levels of super oxide dismutase (SOD) and catalase, indicating the reduction of oxidative stress. Furthermore, the levels of creatinine (Cr), urea and neutrophil gelatinase-associated lipocalin (NGAL) were declined, indicating the improvement in renal function at effective doses of Modafinil (50 and 100 mg/kg) compared to the I/R control group without Modafinil pre-treatment. Our findings suggest that Modafinil holds promise as an effective therapeutic agent to address the clinical challenges associated with kidney IRI reducing the need for hospitalization and potentially alleviating related morbidities.

Juglanin cures polyethylene microplastics-induced testicular damage in rats

The current research was planned to evaluate the ameliorative role of juglanin (Jug) against polyethylene microplastics (PEMP) prompted testicular impairments. 48 rats were allocated in 4 groups: control, PEMP exposed, Jug + PEMP co-administrated and Jug supplemented group. The activities of antioxidant enzyme, inflammatory markers level, hormonal level, the expressions of steroidogenic enzymes, pro-apoptotic and anti-apoptotic protein were assessed after the 56 days of the trial. PEMP intoxication significantly disturbed Nrf-2/Keap-1 pathway and the biochemical profile of rats. However, the administration of Jug markedly increased Nrf-2 and anti-oxidant enzymes expressions, besides decreased the Keap-1 expression. Jug administration also increased Catalase (CAT), super oxide dismutase (SOD) glutathione reductase (GPx), glutathione peroxidase (GSR) and Hemeoxygenase-1 (HO-1) activities. On the other hand, the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) were decreased following Jug administration. Moreover, Jug administration decreased the levels of inflammatory markers. Additionally, Jug administration increased luteinizing hormone (LH), testosterone, follicle-stimulating hormone (FSH) levels and steroidogenic enzymes expression including 17β-hydroxysteroid dehydrogenase (17β-HSD), steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) expressions. Jug administration decreased Caspase-3 and Bax expressions, while increasing Bcl-2 expression. Therefore, the current findings suggested that Jug can remarkably alleviate PEMP induced testicular damage due to its therapeutical potentials.

Mechanism of iron-activated ozone/persulfate coupled oxidation for petroleum-contaminated soil

Soil contamination by petroleum remains a critical environmental challenge. Single oxidation methods, while widely employed for remediation, often exhibit limitations in effectively degrading these contaminants. This hinders their broader application and necessitates the investigation of the complementary effects of commonly employed single oxidation method such as ozone (O3) and persulfate (PS) oxidation to explore their potential for enhanced degradation. In this study, the O3/PS coupling oxidation system activated by iron-loaded activated carbon (Fe@AC) was employed for the remediation of petroleum contaminated soil, and to evaluate the removal efficiency and underlying mechanism for petroleum contaminants. The results demonstrated a significant improvement in the apparent reaction rate constant of the O3/PS/Fe@AC system, recorded at 0.1253 h−1. This rate was approximately twice that of the PS/Fe@AC system (0.0572 h−1) and two orders of magnitude greater than the Fe2+/PS system (0.0014 day−1). Under the conditions of 6 % PS dosage, 0.6 % Fe@AC dosage, a soil-to-water ratio of 1:2, an O3 gas flow rate of 2.5 mg/L, and a pH of 5 at room temperature, the O3/PS/Fe@AC system removed 46.8 % of total petroleum hydrocarbon at an initial concentration of 5000–6000 mg/kg within 3 h. The reaction of the O3/PS/Fe@AC system involved multiple radicals, such as sulfate radicals (SO4•-), hydroxyl radicals (•OH), and superoxide radicals (O2•-), with the reactivity of SO4•- enhanced by O3. This study demonstrates an efficient method for remediating petroleum contaminated soil, providing a theoretical and technical foundation for the application of the O3/PS/Fe@AC system.

Effective magnetic moment modulated perovskite-type oxides towards peroxymonosulfate activation: A high-valent metal species and superoxide radical step-by-step oxidation route

Perovskite oxides are considered as promising catalysts in activating peroxymonosulfate (PMS) for environmental remediation, but the intrinsic properties that govern the activity of perovskites are ambiguous. Herein, a series of perovskite-type oxides La2MeO4 (LMe, where Me = Co, Mn, Cu, and Fe) were reported to activate PMS for improving organic pollutant degradation, while the LCo/PMS system showed impressive performance, achieving over 90 % removal of organic contaminants (dyes and antibiotics) under the optimized conditions of 0.05 g/L catalyst and 0.50 mM PMS. Experiments and characterizations verified a good linear correlation between the catalytic activity and effective magnetic moment (μeff) of catalysts, underlining the key role of the spin state of the metal center in governing the intrinsic activity. Additionally, two stages of oxidation pathways were evidenced to be involved in the reaction: i) high-valent cobalt-oxo species (i.e., Co(IV)) were produced from the surface reactive complexes catalyst-PMS*, afterwards ii) a portion of superoxide radicals (O2•−) were formed via the PMS reaction with Co(IV). Overall, these findings provide new insights into the mechanism of the perovskite-activated PMS system for efficient water remediation.

Evaluation of Nitric Oxide-Donating Properties of 11H-indeno[1,2-b]quinoxalin-11-one Oxime (IQ-1) by Electron Paramagnetic Resonance Spectroscopy.

IQ-1 (11H-indeno[1,2-b]quinoxalin-11-one oxime) is a specific c-Jun N-terminal kinase (JNK) inhibitor with anticancer and neuro- and cardioprotective properties. Because aryloxime derivatives undergo cytochrome P450-catalyzed oxidation to nitric oxide (NO) and ketones in liver microsomes, NO formation may be an additional mechanism of IQ-1 pharmacological action. In the present study, electron paramagnetic resonance (EPR) of the Fe2+ complex with diethyldithiocarbamate (DETC) as a spin trap and hemoglobin (Hb) was used to detect NO formation from IQ-1 in the liver and blood of rats, respectively, after IQ-1 intraperitoneal administration (50 mg/kg). Introducing the spin trap and IQ-1 led to signal characteristics of the complex (DETC)2-Fe2+-NO in rat liver. Similarly, the introduction of the spin trap components and IQ-1 resulted in an increase in the Hb-NO signal for both the R- and the T-conformers in blood samples. The density functional theory (DFT) calculations were in accordance with the experimental data and indicated that the NO formation of IQ-1 through the action of superoxide anion radical is thermodynamically favorable. We conclude that the administration of IQ-1 releases NO during its oxidoreductive bioconversion in vivo.

Effect of proteins from the coelomic fluid of superficially wounded holothurians on the activity of phagocytes

Holothurians are among the most capable of regenerating animals. Their phagocytes are analogues of macrophages, but the mechanisms of their participation in wound healing have not been studied. The aim of the work is to determine the effect of individual protein components isolated from the coelomic fluid of holothurians with superficial damage to the body wall on the functional activity of the two types of phagocytes (P1 and P2) in holothurian Eupentacta fraudatrix. Protein components of the coelomic fluid of holothurians with superficial wounds of the body wall were analyzed and collected by gel permeation chromatography. We used proteins whose content changed significantly during the wound healing period in preliminary experiments. Two proteins and a peptide were added to phagocytes, isolated by gradient centrifugation, simultaneously with the thermostable toxin of Yersinia pseudotuberculosis and incubated for 24 h. The production of superoxide anion radical was determined by the reduction of nitroblue tetrazolium (NBT) using a colorimetric method. To assess the specificity of the proteins, bovine serum albumin (BSA) was used as an internal control. In one-day in vivo experiments, proteins were administered to wounded animals. Two proteins, when compared with the effect of BSA, did not show a specific effect on the production of reactive oxygen species in phagocytes in vitro. However, a comparison of the effect of the peptide on the oxidative activity and viability of phagocytes with those of BSA revealed the specificity of its action. The peptide reduced the oxidative activity of P1 phagocytes and increased it in P2 phagocytes in a direct concentration-dependent manner. One of the two proteins being administered to wounded holothurians caused a multidirectional concentration-dependent effect on the oxidative activity of the two types of phagocytes, with a predominant suppression of the P1 phenotype activity. The ability of protein components to cause a shift in the ratio of oxidative activity of the two types of phagocytes towards the preferential activation of P2 phagocytes, which are considered as functional analogues of M2 macrophages, suggests that they act as anti-inflammatory agents.

Construction of La1−xSrxNiO3/g-C3N4 type-Z heterojunctions with enhanced visible-light photocatalytic degradation of organic pollutants

Lanthanum nickelate (LaNiO3), known for its high visible-light absorption, is a promising photocatalyst for water purification. However, the low conduction band position and high photogenerated carrier complexation rate of pure LaNiO3 limit its photocatalytic activity. To address this issue, we investigated the synergistic effects of doping and constructing heterojunctions. A La0.9Sr0.1NiO3 (20%)/g-C3N4 (L2CN8) heterojunction was successfully created. In addition, various characterisation techniques were then employed to analyse the structure–performance relationships of these heterojunction photocatalysts in degrading organic dyes. Results revealed that at a 10% Sr doping level, the oxygen vacancy content was 0.68, which is significantly higher than that of LaNiO3 (0.05). The increased number of oxygen vacancies enhanced the electron capture ability and improved the separation efficiency of photogenerated carriers. Furthermore, the optimised L2CN8 (20 mg) achieved 81.2% and 73.8% removal of methylene blue (50.0 mL, 10 mg L−1) and tetracycline (50.0 mL, 10 mg L−1) under simulated visible-light irradiation (λ > 420 nm). Furthermore, an active species capture experiment confirmed the significant role of superoxide radicals (·O2−) in the degradation process. Based on these experimental findings, we proposed a rational Z-type charge transfer mechanism. This study holds great importance for water pollution control and environmental protection.

Photocatalytic properties of bismuth-rich Bi4O5I2/BiOBr flowers prepared by one-step solvothermal method were studied

In this paper, bismuth-rich three-dimensional Bi4O5I2/BiOBr hollow flower spheres were prepared by a one-pot solvothermal method. The anionic contaminant Rhodamine B (RhB) was used as the photocatalytic test contaminant. The results showed that the degradation rate of RhB was more than 99 %. Then Br element was introduced into Bi4O5I2 hollow flower balls, the diameter of flower balls decreased and flowers sparsely. With the increase of Br content, flower balls gradually increased in volume and became denser. Small and sparse flower balls increase the specific surface area of flower balls and increase the number of active sites, thus improving the REDOX capacity of photogenerated electrons and holes. Our findings suggest that both holes (h+) and superoxide radical anions (•O2−) are crucial players during photocatalysis. The aim of this study is to develop an efficient photocatalyst for the degradation of organic pollutants, and its photocatalytic mechanism is described theoretically.

Synthesis of Coumarin-Based Photosensitizers for Enhanced Antibacterial Type I/II Photodynamic Therapy.

Photodynamic therapy (PDT) is an effective method for treating microbial infections by leveraging the unique photophysical properties of photosensitizing agents, but issues such as fluorescence quenching and the restricted generation of reactive oxygen species (ROS) under hypoxic conditions still remain. In this study, we successfully synthesized and designed a coumarin-based aggregation-induced emission luminogen (AIEgen), called ICM, that shows a remarkable capacity for type I ROS and type II ROS generation. The 1O2 yield of ICM is 0.839. The ROS it produces include hydroxyl radicals (HO•) and superoxide anions (O2•-), with highly effective antibacterial properties specifically targeting Staphylococcus aureus (a Gram-positive bacterium). Furthermore, ICM enables broad-spectrum fluorescence imaging and exhibits excellent biocompatibility. Consequently, ICM, as a potent type I photosensitizer for eliminating pathogenic microorganisms, represents a promising tool in addressing the threat posed by these pathogens.

Synthesis of activated carbon-supported nano copper oxide and its inactivation performance on Escherichia coli in water

Copper oxide (CuO) is limited in inactivating bacteria due to the deficiency of active Cu(I) that can catalyze dissolved oxygen to produce reactive oxygen radicals. A novel sterilization agent was developed to inactivate Escherichia coli (E. coli) by loading nano copper oxide onto activated carbon (nCuO/AC) with a facile impregnation method. Surface techniques proved that CuO with a size of 100–200 nm was evenly loaded on AC surface, which improved its dispersity and reactivity. XPS analysis further revealed a cycle of surface-bonded Cu(II) to Cu(I) in the nCuO matrix that was driven by reducing groups on AC surface such as hydroxyl. The resultant Cu(I) activated dissolved oxygen to produce reactive oxygen species for bacterial inactivation. Superoxide radical (•O2–) was proved to be the primarily oxidative species during the sterilization process by EPR analysis and quenching investigations. Therefore, the nCuO/AC achieved an enhanced inactivation efficiency of 6.0 log CFU/mL as compared to those of 1.1 and 0.4 log CFU/mL by the nCuO and AC, respectively. The above sterilization reaction was pH-dependent and high inactivation efficiency could be achieved under neutral conditions. Additionally, the nCuO/AC exhibited excellent stability with an inactivation efficiency of 5.4 log CFU/mL after 4 cycles. Spent nCuO/AC showed great potential in renewability because it could inactivate 5.5 log CFU/mL of E. coli by peeling off residual nCuO on AC surface with sulfuric acid and reloading new nCuO through impregnation, with a regeneration rate up to 97.2 %. The above results demonstrated that nCuO/AC could be a promising bactericidal material for water treatment.