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Electrospun carbon nanofibers decorated with Pt-Ni2P nanoparticles as high efficiency counter electrode for dye-sensitized solar cells
摘要： Carbon nanofibers (CNs) supported by Pt and Ni2P nanoparticles (Pt-Ni2P/CNs) are successfully synthesized and explored as counter electrodes for dye-sensitized solar cells (DSSCs) for the first time. Pt and Ni2P nanoparticles are prepared by stabilization and carbonization of electrospun nanofibers, and subsequently controllable Pt and Ni2P nanoparticles are grown on surface of CNs obtained through redox reaction. A series of electrochemical measurements analysis confirm that the Pt-Ni2P/CNs composite have simultaneously superior electrocatalytic activity and enhanced electrical conductivity compared with those of individual CNs and Pt. Accordingly, DSSCs using the composite Pt-Ni2P/CNs as a counter electrode exhibit a excellent photovoltaic performance (power conversion efficiency of 9.11%), which is much higher than conventional Pt/CNs counter electrode (power conversion efficiency of 8.35%), owing to the collective effect of the high electrical conductivity originated from carbon nanofibers and superior electrocatalytic activity arising from Pt/CNs nanoparticles.
关键词： counter electrode,electrospun,dye-sensitized solar cells,Pt and Ni2P nanoparticles,redox reaction
更新于2025-11-14 15:27:09
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A turn-on fluorescent probe for vitamin C based on the use of a silicon/CoOOH nanoparticle system
摘要： The authors describe a fluorometric method for the turn-on determination of vitamin C (ascorbic acid). The blue fluorescence of silicon nanoparticles (SiNPs; with excitation/emission maxima at 350/450 nm) is found to be quenched by CoOOH nanoparticles (NPs). In the presence of vitamin C, the CoOOH NPs are decomposed by a redox reaction between the diol group of vitamin C and CoOOH NPs. As a result, fluorescence recovers. On the basis of this finding, a fluorometric method was designed for the turn-on detection of vitamin C. Under optimal conditions, the method has a low detection limit (0.47 μM) and a linear response in the 0.5 μM to 20 μM a concentration range. It was successfully applied to the determination of vitamin C in spiked red grape and orange juice, and in vitamin C tablets.
关键词： Fluorescence Bturn-on^ strategy,Cobalt oxyhydroxide nanoparticles,Fluorometry,Stern-Volmer plot,Surface energy transfer,Redox reaction,Inner filter effect,Quenching,Silicon nanoparticles
更新于2025-09-23 15:23:52
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MPA-CdTe quantum dots as a??on-off-ona?? sensitive fluorescence probe to detect ascorbic acid via redox reaction
摘要： Mercaptopropionic acid (MPA) capped CdTe quantum dots (MPA-CdTe QDs) were synthesized in aqueous medium by hydrothermal method, which modified by Fe3+ could be used as a fluorescent probe to detect ascorbic acid (AA). MPA-CdTe QDs fluorescence probe could be used as successive sensor for metal ions and AA with "on-off-on" process. The fluorescence of QDs was quenched after adding Fe3+ to MPA-CdTe QDs. Then, the fluorescence of the Fe3+@MPA-CdTe QDs can be sensitively turned on by AA to give an "on–off–on" fluorescence response according to the oxidation–reduction between Fe3+ and AA. There was a linear relationship between fluorescence intensity quenching value and the concentration of Fe3+ in the range of 2–10 μM since Fe3+ sensitively reacted with CdTe QDs. The linear detection range for AA was 0.1–1 μM with a limit of detection of 6.6 nM. The principle is proved by fluorescence emission spectroscopy, nuclear magnetic resonance spectroscopy. The proposed method is successfully used to detect the AA in human plasma sample.
关键词： CdTe quantum dots,Redox reaction,Fluorescent probe,Ascorbic acid
更新于2025-09-23 15:19:57
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Design of Multifunctional Titania-Based Photocatalysts by Controlled Redox Reactions
摘要： This work aims at the preparation of multifunctional titania-based photocatalysts with inherent capabilities for thermal co-activation and stabilisation of anatase polymorph, by designing the phase composition and microstructure of rutile-silicon carbide mixture. The processing involved a conventional solid state route, including partial pre-reduction of rutile by SiC in inert Ar atmosphere, followed by post-oxidation in air. The impacts of processing conditions on the phase composition and photocatalytic activity were evaluated using Taguchi planning. The XRD studies confirmed the presence of rutile/anatase mixtures in the post-oxidised samples. The results emphasise that pre-reduction and post-oxidation temperatures are critical in defining the phase composition, while post-oxidation time is relevant for the photocatalytic performance. Microstructural studies revealed the formation of core-shell particles, which can suppress the photocatalytic activity. The highest apparent reaction rate of the photodegradation of methylene blue was observed for the sample pre-reduced in Ar at 1300°C for 5 h and then calcined in air at 400°C for 25 h. Though its performance was ~1.6-times lower than that for the same amount of nanostructured industrial P25 photocatalyst, it was achieved in the material possessing 2–3 times lower surface area and containing ~50 mol% of SiO2 and SiC, thus demonstrating excellent prospects for further improvements.
关键词： silicon carbide,Taguchi plan,photocatalysis,redox reaction,anatase,TiO2
更新于2025-09-19 17:13:59
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[IEEE 2019 Innovations in Power and Advanced Computing Technologies (i-PACT) - Vellore, India (2019.3.22-2019.3.23)] 2019 Innovations in Power and Advanced Computing Technologies (i-PACT) - Application of Hydroelectric Cell for LED Lamp
摘要： Hydroelectric cells are a new form of renewable energy where we are using water as an energy source. This cell is made of Lithium Substituted Magnesium Ferrite, a nanoporous material in the form of a circular pellet. Zinc and Silver are used as electrodes where Zinc works as anode and Silver as a cathode. The electric charges are generated due to the redox reaction. Water gets absorbed by the material and this physisorption of water generates Hydronium and Hydroxide ions. The Hydroxide ion moves towards Zinc electrode where it forms Zinc Hydroxide and releases electrons and Hydronium ion moves towards Silver electrode and releases Hydrogen gas. Due to this redox reaction charges get developed and current starts flowing. We are working on RKJ51 whose 1-inch diameter pellet gives 920mV open cell voltage and 82mA peak current. As the voltage provided by Hydroelectric cell is not sufficient to power a single LEDs hence there is a need of boosting the voltage. We are making a voltage booster circuit which can boost the voltage of Hydroelectric circuit and can make it useful for LED lighting.
关键词： redox reaction,voltage booster,Hydroelectric Cell
更新于2025-09-16 10:30:52
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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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Disorder Engineering in Monolayer Nanosheets Enabling Photothermic Catalysis for Full Solar Spectrum (250 <b>-</b> 2500?nm) Harvesting
摘要： A persistent challenge in classical photocatalyst systems with extended light absorption is the unavoidable trade-off between maximizing light harvesting and sustaining high photoredox capability. Alternatively, cooperative energy conversion through photothermic activation and photocatalytic redox is a promising yet unmet scientific proposition that critically demands a spectrum-tailored catalyst system. Here, we construct a solar thermal-promoted photocatalyst, an ultrathin “biphasic” ordered–disordered D-HNb3O8 junction, which performs two disparate spectral selective functions of photoexcitation by ordered structure and thermal activated conversion via disordered lattice for combinatorial photothermal mediated catalysis. This in situ synthetically immobilized lattice distortion, constrained to a single-entity monolayer structure not only circumvents interfacial incompatibility but also triggers near-field temperature rise at the catalyst–reactant complexes’ proximity to promote photoreaction. Ultimately, a generic full solar conversion improvement for H2 fuel production, organic transformation and water purification is realized.
关键词： redox reaction,photothermic catalysis,defect engineering,order–disorder,full solar spectrum
更新于2025-09-10 09:29:36
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Spectrophotometric and cyclic voltammetric study of interaction of Fe(iii) with vitamin B3 and vitamin B6
摘要： The interaction of Fe(III) with niacin and pyridoxine was investigated by UV-Vis. spectrophotometry. The metal to ligand ratio for Fe(III)- niacin system was found to be approximately 1 : 3 and for Fe(III)-pyridoxine system it was 1 : 1. The redox properties of uncoordinated Fe(III)/Fe(II) system is reversible at platinum electrode and in presence of the ligands the system was found to be quasi-reversible in nature. It was also found that in every case the system was diffusion controlled.
关键词： Cyclic voltammetry,Redox reaction,Slope ratio method,Continuous variation method,Vitamin B3
更新于2025-09-04 15:30:14
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Correlation between Ni valence and resistance modulation on SmNiO <sub/>3</sub> chemical transistor
摘要： The resistance modulation under various gate voltage (Vg) application conditions was systematically studied for a chemical field effect transistor (FET) composed of a SmNiO3 (SNO) film channel and an ionic liquid gate insulator. The channel resistance of the SNO chemical FET changed nonlinearly over a wide range for different temperatures, Vg magnitudes, and Vg application durations. The correlation between the modulated resistance and the Ni valence state was quantitatively revealed using X-ray photoelectron spectroscopy. A model describing the resistance change with the Vg application conditions was proposed by considering the kinetics of the reduction reaction on the SNO channel. This model enables the resistance to be predicted for given Vg application conditions, and selective resistance modulation over a wide range of resistances has been demonstrated.
关键词： control resistance modulation,nonvolatile,redox reaction,oxygen vacancy,Nickelate thin film
更新于2025-09-04 15:30:14