Journal of Photochemistry and Photobiology A-chemistry最新文献

Dehydroacetic acid analogue (DHA) and 7-(diethylamino)-2-oxo-2H-chromene-3-carbohydrazide (COM) Schiff base ligand (COM-DHA) as dual-mode fluorescence chemosensor was synthesized and structurally characterised by using elemental analysis, FTIR, NMR, and Mass analysis. The free probe COM-DHA shows distinct fluorescence emission at 476 nm, upon interaction with Ni²⁺ the emission intensity was quenched and with Th⁴⁺ the emission intensity was redshirted to 500 nm. Further, the ratiometric fluorescence change (I₅₀₀/I₄₇₆) was used to detect Th⁴⁺, and a turn-off fluorescence probe COM-DHA at 476 nm was used to detect Ni²⁺ ions. The COM-DHA forms a 2:1 stoichiometric complex with both Ni²⁺/Th⁴⁺ ions with an estimated association constant of 4.84 × 10⁴ and 6.68 × 10⁴ M⁻² respectively. A further probe COM-DHA is that it has a wide working pH range (5 to 10) with a short response time (2 to 3 min). The detection limit of COM-DHA towards Ni²⁺ and Th⁴⁺ was found to be 77.8 and 48.7 nM, respectively. The, DFT/TD-DFT calculations and FTIR analysis were used to study the binding mechanism between COM-DAH and Ni²⁺/Th⁴⁺ ions. Furthermore, the proposed probe COM-DHA has successfully quantified trace amounts of Ni²⁺ and Th⁴⁺ in real samples and applied them to the in-vivo bioimaging of Th⁴⁺ in C. elegans model.

Herein, a biocompatible nanocomposite based on guar gum (GG-CuMn₂O₄) was successfully synthesized and utilized for the elimination of toxic Allyl 2,4,6 tribromophenyl ether (ATE), a commonly used plastic additive. The research involved the green fabrication of CuMn₂O₄, which was then integrated into the polymeric matrix of guar gum to form GG-CuMn₂O₄ nanocomposite. The successful creation of the green-synthesized nanocomposite coated with a polymeric matrix at the nanoscale was confirmed by characterization. PXRD analysis revealed a semi-crystalline structure, while microscopic examinations committed the encapsulation of CuMn₂O₄ within a sheet-like structure in nanorange (1–100 nm). Incorporating the CuMn₂O₄ nanocomposite into the GG gel matrix reduced the likelihood of nanocomposite leaching, thereby enhancing material efficiency and biocompatibility. Highest removal of ATE (95 %) was achieved at a concentration of 5 mg L⁻¹ with a catalytic dose of 10 mg, pH 7, and in the presence of Sunlight. The removal of the pollutant followed first-order kinetics, exhibiting Langmuir adsorption. The study examined the release dynamics of ATE from both underwater-expanded packaging materials and electrical wire components over various time intervals, concurrently assessing the degradation characteristics of the leached ATE. LC-MS analysis has corroborated that GG-CuMn₂O₄ demonstrates a profound capacity in disassembling intricate, hazardous pollutant structures into metabolites of enhanced safety, catalytically driven by Sunlight. The polymeric GG-CuMn₂O₄ nanocomposite exhibited remarkable reusability for up to ten consecutive cycles and advocated its sustainability efficiency and industrial applications.

Photocatalysis provides a green and promising strategy for removing nitrogen oxides (NO_x), one of the main pollutants in the atmosphere. However, few studies have been able to utilize the infrared portion of sunlight due to its low energy, which accounts for >50% of the total sunlight. The conversion of infrared light into heat is an effective but flawed approach for photocatalysis, because high temperature cannot only reduce the activation barrier of the reaction and improve the migration rate of charge carriers, but also increase the collision probability of photogenerated carriers. Here, C/PVDF-BaTiO₃ (polyvinylidene fluoride, PVDF) photocatalytic films with bi-pyroelectric effect are designed to boost the full-spectrum solar photocatalytic conversion of NO_x. During the photocatalytic reaction process, the photothermal conversion of carbon and the dual pyroelectricity synergistically enhance and reinforce each other’s effects. The 0.5 wt% C/PVDF-BaTiO₃ film achieves a denitrification efficiency of 60% in a flow reaction, surpassing both the BaTiO₃ and PVDF-BaTiO₃ samples by 25% and 15% respectively.

Furoic acid (FA) is a useful bio-chemicals, which can be used in the production of pharmaceuticals, food additives, flavors, industrial chemicals, biofuels, etc. Oxidation of furfural to FA has been carried out by a thermal catalytic method, but photocatalytic oxidation protocol has not been reported yet. Here, g-C₃N₄-supported Ag nanoparticles (Ag NPs) catalysts with different Ag loading were synthesized and used for the photocatalytic oxidation of furfural to FA under visible light irradiation. The physicochemical and photoelectrochemical properties of the catalysts were systematically investigated by XRD, TEM, XPS, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS), photoluminescence, etc. Compared with the pristine g-C₃N₄, Ag-CN(N₂ + H₂) was found to have better photocatalytic performances in the aerobic oxidation of furfural under visible light irradiation, and the conversion can reach 82 % with a FA yield of 30 %. Importantly, the loading of Ag NPs has a significant effect on the photoelectrochemical properties. Specifically, 0.5 % Ag NPs loading maximized the photocurrent response, indicating that the loading of Ag NPs enhances charge separation and migration under visible light excitation. The introduction of Ag NPs also led to a significant decrease in electrochemical impedance, which promoted the rate of electron transfer at the interface, further confirming the improved photocatalytic efficiency. The addition of Ag NPs broadens the solar absorption and promotes the separation/transport of photo-generated carriers to form “hot electrons”, and provides the active species for furfural oxidation. The reasonable reaction mechanism of the photocatalytic oxidation of furfural to FA was elucidated. This work offers a novel method for the oxidation of furfural to FA in a mild and green way.

Photoelectrocatalytic water splitting is a promising approach to convert solar energy to hydorgen energy. Delicate design of photoanode is crucial for the excellent catalytic activity. Here, a NiFe-LDH/Ni/BiVO₄ composite photoanode was prepared by magnetron sputtering of Ni followed by electrochemical deposition of NiFe-LDH on BiVO₄ photoelectrode. Interestingly, after a concise photoelectron-activation process, a photocurrent of 4.9 mA/cm² (1.23 V vs. RHE) was obtained in neutral solution, which is 4 times of the pristine BiVO₄ photoanode. The photoelectro-activation process not only enhances the photocurrent, but also significantly supresses the positive spiking phenomenon of the photocurrent. A series of characterizaitons including XRD, SEM, EDX, HRTEM, and XPS ect. were performed, which revealed that the photoelectron-activation process led to the reconstruction of the surface structure of NiFe-LDH/Ni/BiVO₄. The dynamic characterizaitons including stepped potential chronoamperometry, steady-state photoluminescence (PL) spectra, open-circuit potential diagrams, and electrochemical impedance spectroscopy (EIS) ect. were performed. It indicates that the activated samples can provide an enhanced internal electric field and enable the charge carriers being efficiently injected into the electrode/electrolyte interface to promote the water oxidation reaction. This investigation provided a facile activation method for BiVO₄-based composite photoanode, and highly increase the PEC performance in neutral condition.

One-electron oxidation of tyrosine primarily results in the formation of di-tyrosine, which can induce crosslinks leading to protein damage. In this study, we investigated the 3-carboxybenzophenone-sensitized photo-oxidation of Tyr derivatives through time-resolved and steady-state photolysis under anaerobic conditions to analyze the effects of blocking groups.

The mechanism for primary and secondary photoreactions in the sensitized photo-oxidation of Tyr derivatives in aqueous solution was presented based on time-resolved analysis and mass spectrometric characterization of photo-oxidation products. Identified di-Tyr products (in addition to those mentioned more often in the literature, such as 3,3′/3,O’) were in some samples presented together with Tyr-CBH adduct (resulting from radical recombination between the tyrosyl radical and CBH^•). This publication discusses the possible coulombic effects of interacting ionic species (sensitizer and quencher) on quenching rate constants and the effect of amine groups and steric factors on the distribution of stable products. However, a crucial finding of this work is that the more blocked the Tyr is, the more di-Tyr isomers are formed, suggesting that Tyr residue in proteins may form several forms of di-Tyr cross-links.

Described in this article the design and synthesis of a simple fluorogenic and chromogenic chemodosimeter C for sensitive and selective detection of sulphite via the 1,4-Michael addition reaction. This chemodosimeter demonstrated high SO₃²⁻ selectivity over other twenty-three competitive analytes in ∼100 % aqueous solution. Chemodosimeter C revealed a 35-fold “turn-on” fluorescence enhancement towards sulphite ions, as well as fluorometric color change from colorless to cyan. The chemodosimeters’ detection limit for sulphite ions was determined to be 0.782 µM. The sensing mechanism was established using ¹H NMR titration, HRMS, and theoretical calculations. Additionally, convenient chemodosimeter C-based test strips and C-treated silica gel were developed for rapid on-site visual detection of sulphite ions.

Mono and dinuclear Zn(salen-type) complexes 1 and 2 are presented as efficient sensing and adsorption materials for HS^-. The addition of HS⁻ provokes colorimetric and fluorometric changes, useful for optical absorption and fluorescence analyses. Moreover, the limit of detection for HS⁻ for both complexes falls in the sub-micromolar range of concentration. The adsorption/desorption process of HS^- nanoporous crystalline sulfonated polyphenyleneoxide (NC-sPPO) films doped with Zn(salen-type) complexes and an interesting recycling-potential of this system in the detection of hydrogen sulfide, even over time, was proven. The presented results provide proof-of-principle that a fluorescent complex immobilized in a suitable thermoplastic polymer could be the right material to use in a HS^- measuring device that might lead to new developments in the field of optical sensing.

Entangled structures are topological architectures often observed not only in the macroscopic world, but also at the molecular level with many examples in biological systems (DNA, RNA). In recent decades, these fascinating entities have aroused considerable interest among chemists with the advent of metallo-supramolecular knots. Notwithstanding the burgeoning of such metal complexes in literature, their use as luminescent emitters as well as systematic studies on their luminescence properties are still extremely limited. In view of this, a theoretical DFT protocol dedicated to luminescence profile simulations of these peculiar “entwined” species is highly desirable. In this work, we propose a robust and affordable DFT computational workflow able to recreate meticulously the emission band-shape of different metallo-supramolecular knots. As a result of a preparatory DFT benchmark, we decided to use HSEH1PBE/LanL2DZ level via Born-Oppenheimer molecular dynamics to explore the change in the coordination environment around the metal centers in the excited state (S1). Thereupon, a detailed recruiting of TD-DFT functionals recommended the mPW3PBE/LanL2DZ level as the most precise and transferable method to model accurately metallo-supramolecular knots emission spectra as metal ions, internal spacers and interlocking modes vary.

Crystallinity of the photocatalyst has a profound impact on its reactivity. Here, flower-like Bi₂MoO₆ microspheres were synthesized via a solvothermal method and subsequently calcined at varying temperatures to regulate the crystallinity and particle size. The thermally treated samples exhibited enhanced photocatalytic oxygen evolution compared to the pristine Bi₂MoO₆. Higher calcination temperatures led to the formation of larger crystallites, significantly boosting the activity. We demonstrate that crystallinity, rather than surface area, plays a more vital role in governing the photocatalytic performance of Bi₂MoO₆. Improved crystallinity can thicken the space charge layer (SCL), resulting in a greater band bending that facilitates the separation of electron-hole pairs. Conversely, poor crystallinity leads to an abundance of surface and bulk defects, promoting electron-hole recombination. Overall, efficient charge separation and suppressed recombination endow the calcined Bi₂MoO₆ with enhanced water oxidation efficiency.