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Real Time Monitoring of a UV Light-Assisted Biofunctionalization Protocol Using a Nanophotonic Biosensor
摘要： A protocol for the covalent biofunctionalization of silicon-based biosensors using a UV light-induced thiol–ene coupling (TEC) reaction has been developed. This biofunctionalization approach has been used to immobilize half antibodies (hIgG), which have been obtained by means of a tris(2-carboxyethyl)phosphine (TCEP) reduction at the hinge region, to the surface of a vinyl-activated silicon-on-insulator (SOI) nanophotonic sensing chip. The response of the sensing structures within the nanophotonic chip was monitored in real time during the biofunctionalization process, which has allowed us to confirm that the bioconjugation of the thiol-terminated bioreceptors onto the vinyl-activated sensing surface is only initiated upon UV light photocatalysis.
关键词： UV light photocatalysis,biofunctionalization,silicon on insulator,nanophotonic sensor,half antibodies
更新于2025-09-23 15:23:52
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Directing energy into a sub-wavelength non-resonant metasurface across the visible spectrum.
摘要： Group 10 metals (i.e. Ni, Pd, Pt) catalyze a wide range of chemical transformations but the weak interaction of their nanoparticles with light hinders their development for photocatalytic applications. Conversely, coinage metals nanoparticles (particularly Ag and Au) exhibit intense localized surface plasmon resonances in the visible spectrum, but are relatively unreactive, limiting the scope and efficiency of their photochemical processes. Here we demonstrate the design, fabrication and characterization of a new structure containing a single layer of Pd nanoparticles that absorbs up to >98% of visible light. Furthermore, the wavelength of absorption is controlled throughout the visible range of the electromagnetic spectrum by modulating the thickness of a supporting metal oxide film. We show that the absorbed energy is concentrated in the nanoparticle layer, crucial for energy conversion applications including photocatalysis and photothermal processes.
关键词： photocatalysis,plasmonics,metasurfaces,palladium,Hot charge carriers,absorbers,critical coupling
更新于2025-09-23 15:23:52
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Rational Management of Photons for Enhanced Photocatalysis in Structurally-Colored Nanoporous Anodic Alumina Photonic Crystals
摘要： A comprehensive study on the engineering of titanium dioxide-functionalized nanoporous anodic alumina distributed Bragg reflectors (TiO2-NAA-DBRs) for photocatalysis enhanced by the “slow photon” effect is presented. The photocatalytic performance of these composite photonic crystals (PCs) is assessed by monitoring photodegradation of a variety of organic molecules with absorbance bands across the spectral regions. This study demonstrates that photocatalytic performance of TiO2-NAA-DBRs is enhanced by the “slow photon” effect when the edges of the PC’s photonic stopband (PSB) fall within the absorbance band of the organic molecules. The photocatalytic performance is significantly enhanced when the PSB’s red edge is in close proximity to the absorbance band of the organic molecules. Overall photocatalytic degradation is also dependent on the total pore length of the PC structure, charge of the organic molecules, percentage of vis-NIR irradiation and matrix complexity (i.e. interfering ions and molecules) when the PC’s PSB is partially or entirely misaligned with respect to the absorbance band of the organic molecules. Finally, the real-life application of TiO2-NAA-DBRs to degrade pollutants such as pesticides in environmental matrices is demonstrated. This study provides new insights into the development of rationally engineered, high-performing, safe and reusable photocatalyst systems.
关键词： Stopband,Pulse Anodization,Photocatalysis,Slow Photons,Photonic Crystals
更新于2025-09-23 15:23:52
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Selective Photooxidation of Amines and Sulfides Triggered by a Superoxide Radical Using a Novel Visible-Light-Responsive Metal–Organic Framework
摘要： Photocatalysis is an efficient and sustainable approach to convert solar energy into chemical energy, simultaneously supplying valuable chemicals. In this study, a novel metal–organic framework (MOF) compound is constructed from anthracene-based organic linkers, which shows visible-light absorption and efficient photoinduced charge generation property. It was applied for triggering photooxidation of benzylamines and sulfides in the presence of environmental benign oxidants of molecular oxygen or hydrogen peroxide. Results show that it is a highly selective photocatalyst for oxidation reactions to produce valuable imines or sulfoxides. We further investigate the underlying mechanism for these photocatalytic reactions by recognizing reactive oxygen species in the reactions. It has been demonstrated that the superoxide radical (O2??), generated by electron transfer from a photoexcited MOF to oxidants, serves as the main active species for the oxidations. The work demonstrates the great potential of photoactive MOFs for the transformation of organic chemicals into valuable complexes.
关键词： sulfide,photocatalysis,metal–organic framework,benzylamine,oxidation
更新于2025-09-23 15:23:52
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<b>Photodegradation of sugarcane vinasse: evaluation of the effect of vinasse pre-treatment and the crystalline phase of TiO<sub>2</sub>
摘要： In this work, the effect of vinasse pre-treatment and anatase content in the photocatalytic degradation of sugarcane vinasse was evaluated. The in nature vinasse was pretreated by coagulation/flocculation using vegetal tannin as coagulant and diluted 1:2 with deionized water. The photocatalytic tests with in nature, pretreated and diluted vinasse were performed for 48 hours under UV radiation using 1 g of catalyst: TiO2 Kronos calcined at 300oC (100% anatase) and 1000oC (34% anatase) and TiO2 P25 (87% anatase). The process of coagulation/flocculation removed about 50, 85 and 97% of COD, color and turbidity of in nature vinasse, respectively. The results showed that despite the slight COD decrease of in nature vinasse, its toxicity was significantly reduced after photocatalytic treatment, especially when TiO2-34 and TiO2-87 were used. This behavior shows that the mixture of anatase and rutile phases showed a positive synergistic effect. Regarding pre-treatment of vinasse, the coagulation/flocculation process was more efficient, promoting the greatest reductions of COD (67%) and toxicity (up to 10 times).
关键词： coagulation/flocculation,photocatalysis,vinasse,toxicity
更新于2025-09-23 15:23:52
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A Selective Earth-Abundant System for CO <sub/>2</sub> Reduction: Comparing Photo- and Electrocatalytic Processes
摘要： The valorization of CO2 via photo- or electrocatalytic reduction constitutes a promising approach toward the sustainable production of fuels or value-added chemicals using intermittent renewable energy sources. For this purpose, molecular catalysts are generally studied independently with respect to the photo- or the electrochemical application, although a unifying approach would be much more effective with respect to the mechanistic understanding and the catalyst optimization. In this context, we present a combined photo- and electrocatalytic study of three Mn diimine catalysts, which demonstrates the synergistic interplay between the two methods. The photochemical part of our study involves the development of a catalytic system containing a heteroleptic Cu photosensitizer and the sacrificial BIH reagent. The system shows exclusive selectivity for CO generation and renders turnover numbers which are among the highest reported thus far within the group of fully earth-abundant photocatalytic systems. The electrochemical part of our investigations complements the mechanistic understanding of the photochemical process and demonstrates that in the present case the sacrificial reagent, the photosensitizer and the irradiation source can be replaced by the electrode and a weak Br?nstedt acid.
关键词： photocatalysis,electrocatalysis,manganese,copper,carbon dioxide utilization
更新于2025-09-23 15:23:52
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Development of a photocatalytic filter to control indoor air quality
摘要： Background: The aim of this work was the development and characterization of a photocatalytic filter for the treatment of indoor air, characterized by a low pressure drop. Methods: The filter (photocatalytic filter) was based on a polyester substrate additivated with active carbon (Carbotex 150-6), treated with a sol of titanium dioxide (Sol 121-AB; NextMaterials Ltd.) and illuminated with UV LEDs to induce photocatalytic activity. Results: Tests showed that this filter, used in a suitable device for air circulation with a very low noise level, had the ability to block solid particulates, to photocatalytically oxidize a major fraction of volatile organic compounds (VOCs) and deactivate all of the bacteria blocked on the filter, in contrast to traditional commercial air filters on which the bacteria remain viable. Conclusions: Activated charcoal filters treated with TiO2 and illuminated by UV LEDs were found to be extremely effective in killing bacteria and effective in decreasing VOC and total suspended particulates (TSP).
关键词： Bacteria,Titanium oxide,Photocatalysis,Filters,Total solid particulate,Volatile organic compounds
更新于2025-09-23 15:23:52
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Photosensitized TiO2 films on polymers – Titania-polymer interactions and visible light induced photoactivity
摘要： Photocatalytic coatings at polymers, showing a visible light induced photoactivity, can be synthesized using a low temperature oxygen plasma treatment of the polymer (PP) followed by deposition of TiO2 nanoparticles and their sensitization with organic ligands. The whole process consists of three major steps: surface activation involving its partial oxidation, immobilization of TiO2 nanoparticles and photosensitization of titania film by impregnation with the solution of organic ligands forming surface Ti(IV) charge transfer complexes. XPS and IR analysis revealed the formation of oxygen-containing groups at the polymer surface upon plasma treatment. These groups participate in the formation of Ti-O-C bonds which ensure a very good adhesion of titania films to polymeric surface. The dip-coating process using an aqueous colloidal solution of TiO2 nanoparticles allows to synthesize a compact coating with a thickness of 100-300 nm. Coordination of catechol-like ligands to surface Ti(IV) centers results in formation of colored charge transfer complexes responsible for absorption of visible light and an effective photoinduced charge separation. Photogenerated electrons and holes can take part in surface redox reactions responsible for degradation of pollutants. Tests with various organic ligands (catechol, 2,3-naphthalenediol, pyrogallol and rutin) revealed, that the titanium dioxide coating modified with catechol was the most photoactive one when visible light irradiation was applied. Presented photocatalytic coatings can be effectively used as self-sterilizing surfaces activated by visible light.
关键词： photocatalysis,XPS analysis,TiO2 coatings,photosensitization,plasma treatment
更新于2025-09-23 15:23:52
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Removal of tetracycline by BiOBr microspheres with oxygen vacancies: Combination of adsorption and photocatalysis
摘要： Oxygen vacancy-containing BiOBr microspheres with dual functions of adsorption-photocatalysis were synthesized by a simple solvothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance spectroscopy (EPR) and UV–vis diffuse reflectance spectroscopy (DRS). BiOBr microspheres with oxygen vacancies exhibited a higher adsorptive and photocatalytic activity for the removal of tetracycline (TC) than that of defect-deficient BiOBr microspheres. After adsorption for 30 min and visible light irradiation for 90 min, about 94 % of TC was removed by oxygen vacancy-containing BiOBr microspheres, and TC removal efficiency performed effectively in a wide pH range from 3.1 to 11.00. Almost all inorganic anions, such as Cl?, SO2?4, PO3?4, CO2?3 and NO?3, inhibited the removal of TC by BiOBr microspheres and their inhibition effects followed the order of PO3?4 > SO2?4 > CO2?3 > Cl? > NO?3. The surface hydroxyl groups had no effect on TC adsorption, and the adsorption of TC on BiOBr was mainly through the anion exchange process. The existence of oxygen vacancies facilitated the generation of superoxide radicals (O2??), which were the dominant reactive oxygen species for TC degradation in BiOBr suspension. The adsorptive and photocatalytic performance of oxygen vacancy-containing BiOBr decreased to different degrees after three cycles mainly due to the formation of surface complex.
关键词： Mechanism,Photocatalysis,Oxygen vacancy,Adsorption,BiOBr microspheres,Tetracycline
更新于2025-09-23 15:23:52
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Visible Light Driven Hydrogen Evolution by Molecular Nickel Catalysts with Time-Resolved Spectroscopic and DFT Insights
摘要： Hydrogen (H2) is a clean fuel that can potentially be a future solution for the storage of intermittent renewable energy. However, current H2 production is mainly dominated by the energy intensive steam reforming reaction, which consumes a fossil fuel, methane, and emits copious amounts of carbon dioxide as one of the byproducts. To address this challenge, we report a molecular catalyst that produces H2 from aqueous solutions, is composed of affordable, earth-abundant elements such as nickel, and has been incorporated into a system driven by visible light. Under optimized conditions, we observe a turnover number of 3880, among the best for photocatalytic H2 evolution with nickel complexes from water?methanol solutions. Through nanosecond transient absorption, electron paramagnetic resonance, and UV?vis spectroscopic measurements, and supported by density functional theory calculations, we report a detailed study of this photocatalytic H2 evolution cycle. We demonstrate that a one-electron reduced, predominantly ligand-centered, reactive Ni intermediate can be accessed under visible light irradiation using triethylamine as the sacrificial electron donor and reductive quencher of the initial photosensitizer excited state. In addition, the computational calculations suggest that the second coordination sphere ether arms can enhance the catalytic activity by promoting proton relay, similar to the mechanism among [FeFe] hydrogenases in nature. Our study can form the basis for future development of H2 evolution molecular catalysts that incorporate both ligand redox noninnocence and alternative second coordination sphere effects in artificial photosynthetic systems driven by visible light.
关键词： Proton relay,Second coordination sphere,DFT calculations,Time-resolved spectroscopy,Visible light photocatalysis,Hydrogen evolution,Molecular nickel catalysts
更新于2025-09-23 15:23:52