- 标题
- 摘要
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- 实验方案
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Robust Cooperative Photo-oxidation of Sulfides without Sacrificial Reagent under Air Using a Dinuclear Ru <sup>II</sup> -Cu <sup>II</sup> Assembly
摘要： A molecular chromophore–catalyst assembly containing a chromophore ruthenium(II) center (RuII chro) and a catalytic copper(II) center (CuII cat) has been prepared easily. The assembly was employed for photocatalytic oxidation of sulfides without sacrificial reagent in the presence of dioxygen under blue light irradiation. Unprecedented turnover number (TON) up to 32 000 was achieved. It was elucidated that an electron transferred from excited state of chromophore RuII* chro to CuII cat along with generation of CuI cat that was further activated by O2. These results demonstrate a promising strategy for efficient cooperative photocatalytic reactions under air using the chromophore–catalyst assembly.
关键词： copper,sulfides,ruthenium,photocatalysis,oxidation
更新于2025-09-23 15:21:21
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[NanoScience and Technology] Silicene (Prediction, Synthesis, Application) || Si Nanoribbons: From 1D to 3D Nanostructures
摘要： In this chapter we give an overview on the theoretical and experimental investigations of one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D) Si nanoribbons (SiNRs) formed on the anisotropic Ag(110) substrate surface. We start by introducing briefly free-standing silicene, a silicon layer with Si atoms arranged in honeycomb lattice, with hexagonal Si-rings as structural units. These hexagonal Si units are subsequently discussed as possible candidates to explain the atomic arrangement of the experimentally synthesized Si nanoribbons on Ag(110). This interpretation is supported by properties such as the presence of the 1D projection of the π and π* bands, forming the so-called “Dirac cones” at the K points of the Brillouin zone, the sp2-like nature of the Si valence orbitals, and the strong resistance against oxidation. Besides these results, the atomic structure as well as the origin of the electronic properties of these Si nanoribbons are still controversially debated in the literature. We address this discussion in the last part of the chapter before summarizing it.
关键词： Si nanoribbons,oxidation resistance,silicene,Ag(110) substrate,Dirac cones,sp2 hybridization
更新于2025-09-23 15:21:21
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Facile synthesis of NaOH-promoted Pt/TiO2 catalysts for toluene oxidation under visible light irradiation
摘要： NaOH-promoted Pt/TiO2 catalysts are successfully prepared by a facile impregnation method assisted by NaOH and tested for the toluene oxidation reaction under visible light irradiation. Keeping molar ratio of Pt:Na =1:8, the 0.1Pt-Na/TiO2 catalyst (0.1 mol% Pt) shows excellent catalytic performance with more than 60% of toluene conversion at 45 oC and achieving total toluene removal at 280 oC, which is significantly better than 0.1Pt/TiO2 catalyst. The structures and properties of catalysts are characterized by XRD, SEM, N2 adsorption, XPS and UV-vis spectra. The positively charged Pt species stabilized by NaOH are the most active sites for photo-thermal catalyzing toluene oxidation. The influence of Pt loading and the effect of supports (active TiO2 and inert Al2O3) are also discussed.
关键词： photo-thermal catalysis,toluene oxidation,TiO2,NaOH,Pt
更新于2025-09-23 15:21:21
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High-throughput laser generation of Si-nanoparticle based surface coatings for antibacterial applications
摘要： High-productivity regime of nanosecond IR-laser ablative generation of silicon colloidal solutions in water for anti-bacterial applications was found in terms of GW/cm2-level laser intensity and scanning velocity by measuring multi-shot ablative mass loss and extinction coefficients of the colloids as sub-linear and third-power intensity functions, respectively. This advantageous regime implies sub-linear mass loss versus laser intensity at the simultaneous third-power yield of nanoparticles, resulting from the subcritical-density, opaque ablative plasma regulating the sample ablation rate and the related plasma-mediated dissociation (dispergation) of the ablation products. In contrast, at higher intensities, there is a drastic increase in mass loss with the corresponding increased yield of (sub) micrometer-sized particles owing to intense plasma-driven expulsion of micro-scale melt droplets and the corresponding saturation of the extinction coefficient of the colloidal solutions because of their dynamic local “self-limiting” effect during the high-rate ablation. The optimal low-intensity regime for Si nanoparticle production demonstrates the monotonous correlated increase of mass loss and extinction coefficient in terms of increasing laser scanning velocity, indicating the diminished cumulative effects. Surface coatings prepared from the generated Si nanoparticles exhibit minor surface oxidation, as acquired as their elemental composition via energy-dispersive X-ray spectroscopy, making their contact angle for water droplets (≈51°) close to that of bare Si wafer (≈58°) with its nanometer-thick native oxide layer. Owing to good wetting, the nanoparticle-based surface coatings show strong antibacterial response regarding Gram-negative Pseudomonas auereginosa bacteria even despite their minor oxidative passivation.
关键词： Silicon nanoparticles,Colloids,Surface oxidation,Extinction coefficient,Wetting,Antibacterial tests,Gram-negative bacteria Pseudomonas auereginosa,Sub-critical ablative plasma,Nanosecond laser ablation,Mass loss
更新于2025-09-23 15:21:21
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Riboflavin-induced Type 1 photo-oxidation of tryptophan using a high intensity 365 nm light emitting diode
摘要： The mechanism of photo-oxidation of tryptophan (Trp) sensitized by riboflavin (RF) was examined employing high concentrations of Trp and RF, with a high intensity 365 nm light emitting diode (LED) source under N2, 20% and 100% O2 atmospheres. Dimerization of Trp was a major pathway under the N2 atmosphere, though this occurred with a low yield (DφTrp = 5.9 x 10-3), probably as a result of extensive back electron transfer reactions between RF●- and Trp(H)●+. The presence of O2 decreased the extent of this back electron transfer reaction, and the extent of Trp dimerization. This difference is attributed to the formation of O2●- (generated via electron transfer from RF●- to O2) which reacts rapidly with Trp● leading to extensive consumption of the parent amino acid and formation of peroxides and multiple other oxygenated products (N-formylkynurenine, alcohols, diols) of Trp, as detected by LC-MS. Thus, it appears that the first step of the Type 1 mechanism of Trp photo-oxidation, induced by this high intensity 365 nm light source, is an electron transfer reaction between the amino acid and 3RF, with the presence of O2 modulating the subsequent reactions and the products formed, as a result of O2●- formation. These data have potential biological significance as LED systems and RF-based treatments have been proposed for the treatment of pathological myopia and keratitis.
关键词： type 1/type 2 mechanisms,dimers,LED,N-formylkynurenine,trimers,riboflavin,photo-oxidation,electron transfer,photobleaching,tryptophan,triplet excited state
更新于2025-09-23 15:21:21
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Non-oxidation reduction strategy for highly selective detection of ascorbic acid with dual-ratio fluorescence and colorimetric signals
摘要： Ascorbic acid (AA), one of the most important vitamins, acts a critical role in various physiological reactions and is involved in many diseases. Thus, the development of highly selectivity methods for detecting AA level with the presence of different reducing substances is of great significance in complicated serum matrix. In this paper, a non-oxidation reduction regulation (NRR) strategy was designed to construct a novel dual-ratio fluorescence and colorimetric dual-readout assay for highly selective detection of AA. The strategy involves three processes: Ag+ oxidated o-phenylenediamine (OPD) to 2,3-diaminophenazine (OPDox), AA inhibited the generation of OPDox and the AA was oxidized to dehydroascorbic acid (DHAA). The specific performance of DHAA NRR, due to the condensation reaction between dicarbonyl group of DHAA and diamine group of OPD, that is confirmed by ESI-MS and 1H NMR spectra analysis, can remarkably enhance the selectivity of AA detection. Additionally, the proposed method based on NRR strategy not only provides a sensing platform for probing AA but also shows promising outlook in biomedical studies.
关键词： O-phenylenediamine,Non-oxidation reduction regulation,Ascorbic acid,Dual-ratio,Dual-readout
更新于2025-09-23 15:21:21
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<i>(Invited)</i> Fabrication Technique for Low-Temperature Aqueous Solution-Processed Oxide Thin-Film Transistors
摘要： Solution-processing of oxide semiconductor is a promising technique for the simple and low-cost fabrication of oxide thin-film transistors (TFTs). We demonstrate improved TFT characteristics by application of a hydrogen injection and oxidation (HIO) process to the fabrication of high-performance low-temperature oxide TFTs. The compatibility of this technique for flexible substrates was also confirmed when the HIO method was applied to solution-processed metal oxide TFTs.
关键词： solution-processing,flexible substrates,low-temperature fabrication,oxide thin-film transistors,hydrogen injection and oxidation
更新于2025-09-23 15:21:21
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Effect of laser shock processing on oxidation resistance of laser additive manufactured Ti6Al4V titanium alloy
摘要： The high-temperature oxidation resistance of laser additive manufactured (LAM) Ti6Al4V before and after laser shock processing (LSP) was investigated. The samples were oxidized at 400?800 °C for 1?50 h in air. The results revealed that the rate of weight gain of the Ti6Al4V fabricated through LAM decreased, and LSP had a positive effect on increasing the oxidation resistance. At an oxidation temperature of 700 °C, an aluminum-rich layer was observed in the cross-section before LSP. After LSP, the aluminum-rich layer changed to three layers. The aluminum-rich layer prevented the diffusion of oxygen, which improved the oxidation resistance of the Ti6Al4V.
关键词： Ti6Al4V titanium alloy,High-temperature oxidation resistance,Laser shock processing,Laser additive manufacturing
更新于2025-09-23 15:21:01
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Blue LED light-driven photoelectrocatalytic removal of naproxen from water: Kinetics and primary by-products
摘要： Here, we demonstrate the viability of a ZnO/TiO2/Ag2Se thin-film composite synthesized on FTO to degrade the drug naproxen in aqueous solutions by visible-light photoelectrocatalysis (PEC). The experiments were made with 100 mL of solutions containing 5 mg L-1 drug and 50 mM Na2SO4 at natural pH, using a cell equipped with a Pt wire as cathode and the composite as photoanode exposed to a 36 W blue LED lamp. Total degradation was achieved after 210 min of electrolysis at anodic potential of +1.0 V/Ag|AgCl. This resulted from the oxidative action of hydroxyl radicals formed via direct anodic water discharge and through mediated water oxidation by photogenerated holes. The degradation rate decreased at higher naproxen concentration, but the treatment efficiency became higher due the deceleration of the parasitic reactions involving hydroxyl radicals. In chloride medium, the photoanode showed a large ability to produce active chlorine, which contributed to the oxidation of the target molecule. LC-QToF-MS analysis of treated solutions revealed the generation of four primary naphthalenic by-products, from which the initial degradation route of naproxen is proposed.
关键词： Photoelectrocatalysis,Water treatment,Oxidation by-products,Blue LED light,Pharmaceutical residue
更新于2025-09-23 15:21:01
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Study on Process of CoNiCrAlY Bonding Layer Under Laser Shock
摘要： In this study, atmospheric plasma spraying was used for the preparation of a CoNiCrAlY bonding layer on a nickel (Ni)-based superalloy with different laser shock times designed for surface modi?cation. In addition, electron-beam physical vapor deposition was used to deposit a ceramic layer to form a new modi?ed coating. When comparing high-temperature oxidation resistance with mechanical properties for both traditional coatings and modi?ed coatings as well as the effects of different laser shock times on them, the results showed that the cross-section hardness of the coating under two laser shocks reaches the peak value of 297 HV, which is 11% higher than that of ordinary coating. The growth rate of the thermal growth oxide at the interface of the modi?ed coatings is signi?cantly lower than that of the ordinary coating under different oxidation times at 1000°C. Furthermore, the lowest rate, 2·43 × 10?4 mm/h, occurs after being laser-shocked twice. With the increase in oxidation time, the residual compressive stress generated during the oxidation increases ?rst and then decreases. Moreover, the stress value of the modi?ed coating after being laser-shocked twice is the smallest. To conclude, this research is of signi?cance for application in surface modi?cation for aviation.
关键词： oxidation,surface modi?cation,coatings
更新于2025-09-23 15:21:01