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Development of Ratiometric Fluorescence Sensors Based on CdSe/ZnS Quantum Dots for the Detection of Hydrogen Peroxide
摘要： In this study, carboxyl group functionalized-CdSe/ZnS quantum dots (QDs) and aminofluorescein (AF)-encapsulated polymer particles were synthesized and immobilized to a sol–gel mixture of glycidoxypropyl trimethoxysilane (GPTMS) and aminopropyl trimethoxysilane (APTMS) for the fabrication of a hydrogen peroxide-sensing membrane. CdSe/ZnS QDs were used for the redox reaction of hydrogen peroxide (H2O2) via a reductive pathway by transferring electrons to the acceptor that led to fluorescence quenching of QDs, while AF was used as a reference dye. Herein, the ratiometric fluorescence intensity of CdSe/ZnS QDs and AF was proportional to the concentration of hydrogen peroxide. The fluorescence membrane (i.e., QD–AF membrane) could detect hydrogen peroxide in linear detection ranges from 0.1 to 1.0 mM with a detection limit (LOD) of 0.016 mM and from 1.0 to 10 mM with an LOD of 0.058 mM. The sensitivity of the QD–AF membrane was increased by immobilizing horseradish peroxidase (HRP) over the surface of the QD–AF membrane (i.e., HRP–QD–AF membrane). The HRP–QD–AF membrane had an LOD of 0.011 mM for 0.1–1 mM H2O2 and an LOD of 0.068 mM for 1–10 mM H2O2. It showed higher sensitivity than the QD–AF membrane only, although both membranes had good selectivity. The HRP–QD–AF membrane could be applied to determine the concentration of hydrogen peroxide in wastewater, while the QD–AF membrane could be employed for the detection of α-ketobutyrate.
关键词： ratiometric fluorescence QD membrane,CdSe/ZnS QDs,hydrogen peroxide,α-ketobutyrate,redox reaction
更新于2025-09-12 10:27:22
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Overall water splitting and hydrogen peroxide synthesis by gold nanoparticle-based plasmonic photocatalysts
摘要： Gold nanoparticle-based plasmonic photocatalysts can be driven by excitation of the localized surface plasmon resonance. Among them, hot-electron transfer-type photocatalysts have recently attracted interest as promising solar-to-chemical converters owing to the wide spectral response from visible-to-infrared light. This Minireview highlights recent studies on two kinds of artificial photosynthesis - water splitting and H2O2 synthesis from water and oxygen - using hot-electron transfer-type plasmonic photocatalysts with particular emphasis placed on the electrocatalysis of Au nanoparticles.
关键词： water splitting,gold nanoparticle,hot-electron transfer,hydrogen peroxide synthesis,plasmonic photocatalysts
更新于2025-09-11 14:15:04
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Preparing p-type ZnO by micro-oxidation of PVD-ZnN
摘要： In this study, a micro-oxidation process was proposed to prepare p-type conductive zinc oxide (ZnO) films. The zinc nitride (ZnN) was used as the precursor and oxidized slightly. During the micro-oxidation, a hydrogen peroxide (H2O2) was used to oxidize ZnN to a nitrogen-contained ZnO material (ZnO:N) at room temperature. Since ZnN film was oxidized slightly, there were N atoms residing within the processed film. The presence of nitrogen (N) atoms in the processed film made the completed ZnO:N being p-type conductive. This p-type conduction was attributed to that these N atoms form “No” states in ZnO:N film, which act as acceptors. The carrier concentration and resistivity of the optimized oxidized ZnN film were 1.36 × 1014 cm?3 and 1.31 × 103 Ω cm, respectively. A good rectified current–voltage characteristic with a turn-on voltage of 2.76 V was achieved for the optimized ZnO/ZnO:N junction.
关键词： ZnO:N,hydrogen peroxide,micro-oxidation,p-type ZnO,ZnN
更新于2025-09-10 09:29:36
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Confined electrochemiluminescence in vertically ordered silica mesochannels for the imaging of hydrogen peroxide released from single cells
摘要： Here, the confined electrochemiluminescence (ECL) of luminol and hydrogen peroxide is achieved in vertically ordered silica mesochannels (SMCs) and applied to map the efflux of hydrogen peroxide from single living cells. The vertical alignment of SMCs on indium tin oxide (ITO) slides restricts the lateral diffusion of species generated in the ECL process. Accordingly, the cross-talk of luminescence intensity from nearby microregions is minimized for higher-spatial-resolution ECL imaging. The characterization of luminol ECL on these SMC-coated slides yields a detection range of hydrogen peroxide between 5 μM and 1 mM, providing high sensitivity in imaging the efflux of hydrogen peroxide from cells. Compared with the luminescence from individual cells on bare ITO slides, ~ 4-fold intensity is observed for SMC-coated ITO, suggesting a better electrode surface for single-cell ECL imaging.
关键词： single-cell imaging,hydrogen peroxide,silica mesochannels,confined electrochemiluminescence,luminol
更新于2025-09-10 09:29:36
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Hydrogen Peroxide Enhances the Antibacterial Effect of Methylene Blue-based Photodynamic Therapy on Biofilm-forming Bacteria
摘要： Recently, increased attention has been focused on endoscopic disinfection after outbreaks of drug resistant infections associated with gastrointestinal endoscopy. The aims of this study were to investigate the bactericidal efficacy of methylene blue (MB)-based photodynamic therapy (PDT) on Pseudomonas aeruginosa (P. aeruginosa), which is the major cause of drug resistant post-endoscopy outbreak, and to assess the synergistic effects of hydrogen peroxide addition to MB-based PDT on biofilms. In planktonic state of P. aeruginosa, the maximum decrease was 3 log10 and 5.5 log10 at 20 and 30 J / cm2, respectively, following MB-based PDT. However, the maximum reduction of colony forming unit (CFU) was decreased by 2.5 log10 and 3 log10 irradiation on biofilms. The biofilm formation was significantly inhibited upon irradiation with MB-based PDT. When the biofilm state of P. aeruginosa was treated with MB-based PDT with hydrogen peroxide, the CFU was significantly decreased by 6 log10 after 20 J / cm2, by 7 log10 after 30 J / cm2 irradiation, suggesting significantly higher efficacy than MB-based PDT alone. The implementation of the combination of hydrogen peroxide with MB-based PDT through working channels might be appropriate for preventing early colonization and biofilm formation in the endoscope and post-endoscopy outbreak.
关键词： methylene blue,endoscopic disinfection,hydrogen peroxide,Pseudomonas aeruginosa,photodynamic therapy,biofilm
更新于2025-09-10 09:29:36
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Removal of Carbofuran in aqueous solution by using UV-irradiation/hydrogen peroxide
摘要： Pesticide residues in natural water are one of the biggest environmental problems. carbofuran is an insecticide widely used in agricultural activities and it is easily biodegradable. Although this compound has a relatively short lifetime in soils and its persistence in the environment varies from one to several weeks. For this reason, the elimination of carbofuran residual from contaminated waters using suitable technique is of environmental interest. The aim of this study to investigate the synergetic effect of UV and UV with hydrogen peroxide on the degradation of carbofuran in aqueous solution. 50 mgL-1 aqueous solutions of carbofuran (CBF) were prepared. The solutions were exposed to various UV irradiation times. The irradiation time varied from (15-240 min). Hydrogen peroxide was set at 4.8 mM as a minimum concentration level. To follow the degradation percent, formaldehyde concentration, and to identify the intermediates by-products, GC-MS, IC, and UV-Visible spectrophotometer were used. The pH, total acidity, and dissolved oxygen values were determined before and after treatment with UV irradiation with/without hydrogen peroxide. Depending on the results obtained the mechanism pathway (degradation) was suggested. The complete removal of carbofuran in aqueous solution took place at 180 min in the presence of H2O2.
关键词： advanced oxidation processes (AOP’s),hydrogen peroxide effect,Carbofuran,UV/H2O2
更新于2025-09-10 09:29:36
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Degradation of dimethyl phthalate using a liquid phase plasma process with TiO2 photocatalysts
摘要： The liquid phase plasma (LPP) method with a TiO2 photocatalyst and hydrogen peroxide was used to decompose dimethyl phthalate (DMP). As the applied voltage, pulse width, and frequency were increased, the rate of decomposition was increased and the decomposition rate was 63% for 180 min under plasma optimum conditions. The addition of TiO2 photocatalyst and hydrogen peroxide increased the DMP decomposition reaction rate, but an excess cause a decrease in decomposition rate due to a decrease in conductivity, blocking of ultraviolet light, and scavenger effect. When the TiO2 photocatalyst and hydrogen peroxide were used together, the decomposition reaction rate of DMP was greatly improved by using LPP single process alone. Also, when all the processes were used at the same time, the decomposition reaction rate was improved to about 2.8 times. DMP undergoes bond cleavage and ultimately decomposes into CO2 and H2O via dimethyl 4-hydroxyphthalate and methyl salicylates due to hydroxyl radicals and various active species generated by the LPP reaction.
关键词： Synergy effect,Hydrogen peroxide,Hydroxyl radicals,Decomposition rate,Degradation reaction pathway
更新于2025-09-09 09:28:46
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Modeling and Optimization of the Photocatalytic Reduction of Molecular Oxygen to Hydrogen Peroxide over Titanium Dioxide
摘要： This study focuses on understanding the mechanisms for optimization of the photocatalytic hydrogen peroxide production over TiO2 (Aeroxide P25). Via precise control of the reaction parameters (pH, temperature, catalyst amount, oxygen content, sacrificial electron donor and light intensity) it is possible to tune either the apparent quantum yield or the production rate. As a result of the optimization, apparent quantum yields of up to 19.8 % and production rates of up to 83 μM min-1 were obtained. We also observed a light dependent change of the reaction order and an interdependency of the light intensity and catalyst amount and developed a well-fitting kinetic model for it, which might also be applied to other reactions. Furthermore, a previously unreported inactivation of the photocatalyst in case of water oxidation is described.
关键词： titanium dioxide (TiO2),hydrogen peroxide (H2O2),oxygen reduction,catalyst inactivation,light intensity,photocatalysis
更新于2025-09-09 09:28:46
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Impact of Hydrogen Peroxide on Photocatalytic Destruction of Anionic SAS in a Reactor with Immobilized TiO2
摘要： Using sodium dodecylbenzenesulfonate the article showed high efficiency of photocatalytic system H2O2/TiO2/UV for deep destruction (~ 90% in terms of TOC) of anionic SAS in a aqueous medium (C0 = 50 mg/dm3, pH0 5.9) in a reactor containing wide-porous ceramic block with immobilized TiO2 on its surface. The TiO2 film for a long time preserved a stable photocatalytic activity
关键词： titanium dioxide,sodium dodecylbenzolsulfonate,hydrogen peroxide,photocatalysis,oxidation,anionic SAS
更新于2025-09-09 09:28:46
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<i>In vitro</i> evaluation of visible light-activated titanium dioxide photocatalysis for in-office dental bleaching
摘要： The evaluation of the photocatalysis of visible light activated titanium dioxide employed in hydrogen peroxide (H2O2) was carried using seven H2O2 solutions (3.5 and 35%) and/or methylene blue (MB), with or without light irradiation (LI); the absorbance of MB was the bleaching indicator. Color analysis was performed on bovine teeth (n=12) using two different concentrations of H2O2, 6 and 35% associated with titanium dioxide (TiO2). Data were analyzed with one and two-way ANOVA, and significance level of p<0.05. Solutions containing MB, H2O2 at 3.5 or 35%, and TiO2, followed by LI, showed significant difference when compared with other groups. Greater MB reduction was found in 35% concentration. H2O2 35%+TiO2 gel showed no difference in comparison to control group. All groups for the color analysis assay showed ΔE higher than 3.3. In conclusion, TiO2 and H2O2 association is a promisor alternative for reducing the clinical time of in-office dental bleaching.
关键词： Hydrogen peroxide,Tooth bleaching,Titanium dioxide
更新于2025-09-09 09:28:46