Journal of Photochemistry and Photobiology A-chemistry最新文献

A highly selective and sensitive assay for Al (III) has been reported. A series of unsymmetrical trisubstituted 1,3,5-triazine compounds were synthesized using a one-pot method, in which probe 8-((4,6-diphenyl-1,3,5-triazin-2-yl)oxy)quinoline (2a) utilized for the detection of aluminum ions. The fluorescence characteristics of the 2a probe were then thoroughly studied, including its selectivity towards various metal ions, solvent effects, ion interference testing, response time, maximum detection limit, Job’s curve analysis, and research on the reversibility of EDTA. The linearity of the fluorescence concentration titration was found to be good within the range of 100–300 μM with R² = 0.981 for Al³⁺. The minimum detection limit was determined to be 0.29 μM and the response time was only 10 s. These results indicate that probe 2a exhibits a specific response to Al³⁺ and holds great potential for application in aluminum ion detection.

In this paper, a meaningful pH sensor (E)-4-(4-(1,2,2-triphenylvinyl) styryl)quinoline (TPQ) with aggregation-induced emission (AIE) effect was synthesized based on the conjugated 4-(1,2,2-triphenylvinyl)benzaldehyde and 4-methylquinoline connected by a CC bond. The conjugated quinoline moiety acts as a proton acceptor, and the small variations of pH value in the linear range of 4.01–7.03 and 7.96–9.45 can cause obvious fluorescence fluctuations. The TPQ has good selectivity and reversibility in pH detection, and importantly, it can detect pH fluctuations in real-time in practical applications by fluorescent means. Moreover, TPQ can also be used as a potential viscosity fluorescence sensor for organic solvents. In addition, by combining various color changes of TPQ caused by acid, alkali, water and ammonia stimulation under sunlight and 365 nm ultraviolet light irradiation, it provides a novel concealed optical anti-counterfeiting technique with high security. Therefore, TPQ is a multifunctional molecule with great potential for applications in pH, viscosity sensing and anti-counterfeiting.

A potentially active fluorescent chemosensor (E)-2-(((2-(1H-benzo[d]imidazol-2-yl)phenyl)imino)methyl)-5-(diethylamino)phenol (BMDP) is developed by the condensation of 2-(2-aminophenyl)-1H-benzimidazole and 4-(diethylamino)salicylaldehyde. It shows an exceptional ratiometric fluorescence behavior when exposed to Zn²⁺ ions and the photoluminescence color is changed from blue to cyan under the exposure of a 365 nm UV light which is also strongly evident from the color chromaticity diagram. The exceptional ratiometric fluorescence behavior in the presence of Zn²⁺ ions is found to be due to the chelation-enhanced fluorescence (CHEF). The 1:1 stoichiometry of BMDP and Zn²⁺ ions in Zn²⁺ ions chelated BMDP complex is confirmed through Job’s plot analysis. Remarkably, Cd²⁺ does not interfere with the selective ratiometric fluorescence behavior induced by Zn²⁺ ions. The lowest detection limit and quantification limit are estimated to be 28 nM and 92 nM respectively. The cyan fluorescence of the Zn²⁺ ions chelated BMDP complex is interestingly reversed to the original BMDP in the presence of ethylenediamine tetraacetic acid (EDTA). At the molecular level, this can be thought of as a complimentary “INHIBIT” logic gate. Furthermore, it is possible to utilize the probe for on-site identification in test strips with improved Zn²⁺ ions selectivity. We have also used a smartphone-based method to demonstrate the usefulness of BMDP for the immediate quantification and detection of Zn²⁺ ions. In light of this, probe BMDP is a trustworthy fluorescence probe for on-site monitoring that can accurately identify Zn²⁺ ions even when some other metals and anions compete.

Green synthesis of MOF-on-MOF is an effective method to prepare the environmentally friendly photocatalyst using metal–organic frameworks (MOFs). Herein, ZIF-8 was synthesized on MIL-100 (Fe) (ZM composites) with different weight percent ratios of ZIF-8 and denoted as ZM21, ZM11 and ZM12. They were investigated as environmentally friendly photocatalysts for the degradation of Methylene Blue (MB) using visible light. XRD, FT-IR, SEM, EDX, and DRS were used to characterize the synthesized materials (ZIF-8, MIL-100, ZM21, ZM11, and ZM12). The ZM11 composite had the highest dye degradation ability. The MB photocatalytic degradation for the ZIF-8, MIL-100, ZM21, ZM11, and ZM12 were 12.59%, 31.27%, 29.45%, 86.3, and 31.51%, respectively. MB degradation by ZM11 composite followed the first-order kinetic model. The effective radical for the MB photocatalytic degradation was the superoxide radical (•O₂^–). The ZM11 composite had the ability of 76% dye removal from water after 3 cycles of MB degradation.

The photocatalytic reduction of CO₂ to hydrocarbons may be a promising mechanistic route to reduce greenhouse gas CO₂, convert it into useful products, and limit the direct emission of CO₂. The photocatalytic reduction of CO₂ is a reaction in which photons activate the photocatalyst by generating reduced and oxidized sites, that are re-oxidized and re-reduced by the reactants. The photocatalytic reduction of CO₂ can produce various products, including CO, formic acid, formaldehyde, methanol, methane, etc.

Here, the activity/selectivity of produced hydrocarbons in the presence of oxygen on various photocatalysts (TiO₂, 5 wt%Cu-TiO₂, 5 wt%Cu-C-TiO₂) was determined. The reaction rate increased with increasing reaction time up to the first half an hour of the reaction but then started to decrease with photocatalysts, indicating photocatalyst deactivation, a rate-limiting step by hydroxyl radicals and adsorption of intermediates on TiO₂. Carbon deposition as the origin of photocatalyst deactivation was confirmed using the TGA of the spent photocatalyst. Additionally, absorption of intermediates on spent catalysts were confirmed by FTIR. On the other hand, the conversion increased with time when copper was used as a promoter on a TiO₂ compared with TiO₂ due to its larger surface area and having more active sites.

The photocatalysts were characterized using BET, ICP-OES, XRD, TGA, XPS, Fourier-Transform Infrared Spectroscopy (FTIR), and UV–Vis. The focus of this study was to determine the activity and efficacy of different photocatalysts (TiO₂, 5 wt%Cu-TiO₂, 5 wt%Cu-C-TiO₂) by gas phase measurement, with a particular emphasis on obtaining reproducible data on conversion and selectivity as a function of irradiation time.

The copper on TiO₂ was found to be more selective towards sodium formate/formic acid with a maximum selectivity of ∼90 % in 4 h and had higher activity (74.3 µmol g_cat^-1 h-1). A maximum CO with a selectivity of 86 % was found when TiO₂ was used in 4 h.

Copper transfer electrons on the TiO₂ surface enhance CO₂ adsorption on the catalytic surface and is the reason for having higher valuable product on Cu-C-TiO₂ and Cu-TiO₂ compared with TiO₂. Carbon in this experiment did not have a role and its effect was negligible.

Photocatalytic water treatment can be promising for eliminating toxic pollutants via a more sustainable approach using renewable sources. However, the technique still requires materials design to optimize/maximize the performance of the photocatalytic materials. Immobilizing the thin film photocatalytic materials onto high surface area textile substrates via atomic layer deposition (ALD) can offer a practical design approach. Al-doped ZnO (AZO) ALD films are deposited onto glass fabric substrates, and their photocatalytic performances were investigated in relation to the FESEM, XRD, XPS, UV–Vis, and PL characterizations. The amount of Al and the post-deposition annealing changed the materials structure, thus the photocatalytic activity of the films. Maximum performance was achieved with the 20 % Al-doped ZnO films after a post-deposition thermal annealing step at 450 °C. The sample also showed the highest UV–Vis absorption and PL emission among the samples. However, this sample didn’t show any crystal peaks in the XRD analysis. Furthermore, the charge carrier concentrations and the mobility of the films were investigated via Hall-Effect, which showed that the 20 % AZO sample has very different features with a p-type nature compared to the other AZO films.

The present study accounts for the enhanced nonlinear optical and optical limiting activity of 7-diethylamino-4-methyl coumarin (7DMC) after the addition of silver nanoparticles. The theoretical calculations were done in three different solvents water, methanol, and dimethyl formamide (DMF), and on the basis of the energy gap, DMF was selected as the most suitable solvent. Further, the liquid samples were prepared in DMF. The natural bond orbitals show the active participation of the lone pairs of electrons of 2O and 35Ag as donor and acceptor moieties respectively. The values of first-order hyperpolarizability of the 7DMC+Ag₃ combination were raised to 2002.71 × 10⁻³⁰ esu, 778.72 × 10⁻³⁰ esu, and 677.12 × 10⁻³⁰ esu in water, methanol, and DMF. The valley-like structure in the Z-Scan spectra indicated the occurrence of reverse saturable absorption in the prepared samples. The optical limiting threshold of the 7DMC+AgNps was decreased from that of the probe 7DMC and AgNps indicating the early attenuation of the optical limiting nature of the combination. Thus, the overall results validated the enhanced optical nonlinearity of the combination. Moreover, it can be stated that the proposed nanoparticles combination 7DMC+AgNps has potential candidature to be used for the fabrication of laser safety devices and eye aids.

4′-phenylterpyridine (TPY) involves four conjugated rings, leading to a multi-resonant chromophore with exceptional luminescent features. Further functionalization of the 4′-phenyl moiety enables a versatile set of chemosensors. In the series, the optical transitions remain similar, where λ_max ranges from 253 to 269 nm, with emissions from 357 to 365 nm. Calculations of the natural transition orbitals NTOs deliver the localized hole-electron densities, indicating that the electronic transitions vary as a local-excitation (LE), charge transfer (CT), and mixed LE-CT along with the set. We employ the energy decomposition analysis to evaluate the possible coordination toward Zn(II), Cd(II), and Hg(II) cations, showing a favorable formation of complexes, where the interaction nature exhibits a ∼ 49 and ∼ 50 % electrostatic and orbital character for the Zn(II), Cd(II) and Hg(II) centers. Furthermore, the density deformation channels confer an explicit picture of the bonding scheme, denoting π- and σ-bonding contributions.

Antibiotic contamination possesses several adverse effects including antibiotic resistance, ecological impact, and human health concern etc. Hence there is need to find ways in mitigation of this environmental issue. In this study, Cu₂ZnSnS₄ (CZTS) nanoparticles (NPs) and CZTS-WS₂ composite were synthesized and explored its photocatalytic efficiency in degrading sulfamethoxazole, an antibiotic. In addition, the antioxidant and antibacterial capabilities of CZTS NPs and CZTS-WS₂ composites were also investigated. The CZTS NPs and CZTS-WS₂ composites were synthesized by a modified hydrothermal method, and the physical properties were explored. The p-type pristine CZTS NPs semiconductor with a direct bandgap (1.49–1.51 eV) is non-toxic and has a remarkable photostability making it extremely valuable in light-harvesting and photocatalyst applications. Quaternary CZTS NPs loaded with 10 % WS₂ exhibits good photocatalytic activity for the breakdown of sulfamethoxazole. The Fenton procedure was used to extract sulfamethoxazole from an aqueous solution. When compared to CZTS NPs (0.088 min⁻¹), the apparent rate constant for CZTS-WS₂ composite (0.223 min⁻¹) is almost two and a half times higher. Reactive quenching studies showed that OH, O²⁻, and ¹O² all contributed to SMX deterioration, with ¹O² outperforming O²⁻ and OH. An SMX transformation pathway in the CZTS-WS₂ composite process was postulated based on the identified intermediates by LC/MS. Finally, the composite’s reusability and stability were assessed during five separate runs. CZTS-WS₂ composite demonstrated more than 80 % radical scavenging efficiency. CZTS NPs and CZTS-WS₂ composite also demonstrate antibacterial capabilities against E. coli, S. aureus, M. luteus, and C. albicans. This is the first paper on the photocatalytic study of the degradation of sulfamethoxazole using CZTS NPs and CZTS-WS₂ composite as catalysts. The current CZTS-WS₂ composite’s outstanding catalytic efficacy in the absence of severe oxidizing/reducing agents and pricey noble metals has been ascribed to its size, surface area, and electronic effect. Hence this work describes a novel approach to developing efficient materials for antioxidant, antibacterial, and photocatalysts for the degradation of sulfamethoxazole.