New Journal of Chemistry最新文献

Developing highly stable, low-cost, and efficient electrode materials for supercapacitor and oxygen evolution reactions is a challenging issue in energy storage and generation technology to meet the demand for sustainable and clean energy. Herein, cobalt phosphates in comparison with cobalt oxides were synthesized using a successive ionic layer adsorption and reaction (SILAR) method on a nickel foam substrate with different crystallization temperatures, and their supercapacitor and oxygen evolution reaction performances were studied. The nanorod bundles of cobalt phosphate electrodes prepared at 150 °C delivered an excellent specific charge storage capacity of 1512 F g⁻¹ (681 C g⁻¹) at a current density of 5 mA cm⁻², which is higher than that of cobalt oxide (1103.9 F g⁻¹ (496 C g⁻¹)). They are highly stable for more than 2000 charge–discharge cycles with a coulombic efficiency of 93%. Furthermore, the same electrodes exhibited enhanced electrocatalytic behaviour for the oxygen evolution reaction (OER) with an overpotential of 359 mV at a current density of 30 mA cm⁻², lowest Tafel slope of 60 mV dec⁻¹ and stability of 20 hours. Enhanced reaction kinetics are attributed to the high electrochemical surface area with a C_dl of 594 μF and improved electronic conductivity. The above results indicated that cobalt phosphate is one of the most efficient electrode materials for the OER and supercapacitors.

Copper magnesium tin sulfide (CMTS) is a multifunctional material that has recently generated a lot of interest as a potential new photocatalyst for organic pollutant degradation. Some of the desirable characteristics of CMTS are its narrow band gap energy, good chemical and photochemical stability, and high relative abundance of its constituent elements. In this work, CMTS (with the empirical formula Cu_0.5Mg_2.5SnS₄) and type-II heterojunction CdS@CMTS composites with varying CdS contents have been synthesized using a cost-effective and energy-efficient microwave-assisted method. X-ray diffraction analysis confirmed the presence of kesterite CMTS and hexagonal CdS in the composites. After the addition of CdS, the effective band gap energy of CMTS increased from 2.07 to 2.40 eV. The composites exhibited a uniform distribution of CdS on the CMTS surface. Photocatalytic studies reveal that CdS@CMTS exhibits higher photocatalytic activity for the degradation of brilliant green (BG) dye under visible light irradiation in comparison to pristine CMTS. Among the synthesized materials, the 30% CdS@CMTS exhibited the highest photocatalytic activity, with up to 95.8 ± 1.45% degradation of BG within 5 h. Thus, CdS@CMTS prepared by microwave-assisted synthesis has shown potential to degrade organic pollutants for wastewater remediation.

Environmental pollution, especially caused by organic pollutants and heavy metal ions, seriously threaten the ecological environment and human health. In this work, UIO-66-NH₂, with fluorescence emission at 426 nm, was synthesized. It was found that with the increase in the concentration of o-phenylenediamine (OPD) in UIO-66-NH₂ solution, the fluorescence at 426 nm was enhanced, which could be used to quantify the OPD content. In addition, with the increased concentration of Ag⁺, fluorescence of the UIO-66-NH₂/OPD system decreased at 426 nm, while a new fluorescence peak appeared at 556 nm. Based on the changes in the fluorescence property of the UIO-66-NH₂/OPD system before and after the additon of Ag⁺, a quantitative analysis of Ag⁺ concentration (0.31–225 μM) by the ratio of F426/F556 was realized. This strategy used UIO-66-NH₂ as the probe to realize the continuous determination of organic pollutants and heavy metal ions, providing a new idea for the detection of pollutants.

Air filtration materials can protect humans from the invasion of airborne pathogens. However, pathogens intercepted by air filters can survive in fibrous materials and pose a threat to human health if they proliferate in large quantities. Therefore, in this work, modified hydro-charged polypropylene (PP) melt-blown nonwovens with antibacterial properties were prepared to reduce the infection rate during the filtering process. Firstly, PP_m electret melt-blown nonwovens containing 5 wt% electret masterbatch PP-MgSt were prepared by the melt-blown process and hydro-charging technology. Then, an N-halamine compound, 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC), was used for antibacterial modification. MC was evenly coated on the surface of the melt-blown fibers by spraying and dipping processes to obtain PP_m/MC-s and PP_m/MC-d melt-blown samples, respectively. The PP_m/MC-s and PP_m/MC-d samples demonstrated excellent antibacterial properties, killing 99.99% of E. coli and S. aureus in 5 and 10 minutes of contact times, respectively. However, the filtration results indicated that the surface coating treatment reduced the filtration efficiency of both samples to varying degrees. Specifically, the filtration efficiency of PP_m/MC-s decreased from 99.64% to 94.77%. Due to the excessive use of ethanol during the PP_m/MC-d modification process, more electret charges escaped, resulting in a significant decrease in filtration efficiency to 69.66%. Comprehensive analysis proposed that melt-blown nonwovens that have already been processed and formed are more suitable for MC antibacterial modification by spraying method. The modified melt-blown samples can provide strong antibacterial effects while maintaining high filtration efficiency and low pressure drop. This work provides a feasible industrialized antibacterial modification method for formed melt-blown filtration nonwovens, which can further improve the protective performance of traditional filter products.

Due to their excellent capabilities in photodynamic therapy (PDT) and aggregation-induced emission, (AIE) photosensitizers have attracted a great deal of attention. However, the poor water solubilities of current AIE photosensitizers limit their widespread in vivo application and PDT productivity. AIE photosensitizers with triphenylamine as electron-donating moiety and pyridine as electron-absorbing group can enhance the D–A effort, thus improving the intramolecular charge transfer (ICT) and extending the emission wavelength. At the same time, ΔE_st was reduced and intersystem crossing processes was promoted due to the D–A effect of the photosensitizers, thus increasing the probability of ROS generation. Herein, a dual-organelle targeted and viscosity-sensitive infrared AIE photosensitizer (NES-OH) with a D–A structure was developed and synthesized. The NES-OH had good water solubility and good linear relationship with concentration. The NES-OH exhibited bright fluorescence at 620 nm with a quantum yield of 66.75% and had high ¹O₂ generation efficiency, as well as good biocompatibility and photostability. The NES-OH can target mitochondria and lysosomes and also monitor lysosomes and mitochondrial viscosity changes in real time or in situ in living cells. More interestingly, in the acidic environment of cancer cells, the structure of the NES-OH changed with the appearance of specific morpholine groups, leading to the targeting of lysosomes and further distinguishing and detecting normal and cancer cells. The in vitro and in vivo study demonstrated that the NES-OH can inhibit tumor growth efficiently upon light exposure. This work constructed an effective photosensitizer for diagnosing and treating cancers and evaluating PDT efficacy.

Expression of concern for ‘Sonochemistry: a good, fast and clean method to promote the removal of Cu(II) and Cr(VI) by MWCNT/CoFe₂O₄@PEI nanocomposites: optimization study’ by Mohammad Hassan Omidi et al., New J. Chem., 2018, 42, 16307–16328, https://doi.org/10.1039/C8NJ03277G.

The synthesis of donor–acceptor conjugated polymers presents a challenge due to the reliance on costly transition-metal catalysts and potentially hazardous reagents, which can have adverse environmental impacts. Aldol polycondensation offers a promising, metal-free alternative for the polymerization of such materials. In this study, we describe the synthesis of three new symmetrical reduced bis-indolinone derivatives. Polymers ADRI, ADTRI and ADCRI were prepared through aldol condensation reactions between diformyl-dithienopyrrolobenzothiadiazole (DTPBT) and bis-indolinones. Photophysical, electrochemical, and thermogravimetric analysis, atomic force measurement (AFM) analysis, gel permeation chromatography (GPC), powder X-ray diffraction (PXRD), density functional theory (DFT) calculations and space charge limited current (SCLC) hole mobility measurements were performed for these polymers. Photophysical and electrochemical studies revealed high visible light absorptivity, along with HOMO energy levels close to −5.9 eV and low-lying LUMO energy levels near −4.0 eV for all polymers. TGA showed that all polymers were quite stable up to ∼300 °C. The measured values of the SCLC hole mobilities of polymers ADRI, ADTRI and ADCRI were 3.90 × 10⁻² cm² V⁻¹ s⁻¹, 8.73 × 10⁻² cm² V⁻¹ s⁻¹ and 8.51 × 10⁻² cm² V⁻¹ s⁻¹, respectively.

This study was conducted to determine the total polyphenol content, antioxidant activity and tyrosinase inhibitory activity of ethanol/water extracts of rhizomes of Vietnamese Zingiber officinale, Curcuma longa, Alpinia officinarum Hance, and Boesenbergia pandurata (Roxb.) Schltr. Total polyphenol content was determined by the Folin–Ciocalteu method, antioxidant activity was evaluated through the DPPH (2,2-diphenyl-1-picryl hydrazyl) free radical scavenging method, and tyrosinase inhibitory activity was estimated using the substrate of 3,4-dihydroxy-L-phenylalanine (L-DOPA). Qualitative results showed that all ethanol/water extracts contained phenolic compounds. The total polyphenol content of the extracts was higher than that determined in previous research, of which the Zingiber officinale extract had the highest value (188.52 ± 2.52 mg GAE per g) and the Boesenbergia pandurata (Roxb.) Schltr extract (61.32 ± 1.72 mg GAE per g) had the lowest value. Compared with the positive control substances used, of the four extracts, the Zingiber officinale extract also showed the best ability to inhibit DPPH free radicals with IC₅₀ = 35.04 ± 2.82 μg mL⁻¹, and the Curcuma longa extract showed the best tyrosinase enzyme inhibition ability with IC₅₀ = 26.07 ± 0.79 μg mL⁻¹.

Contaminants sequestration by iron oxides are of particular relevance in environmental chemistry and Fourier transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) mode is used in this study to investigate the molecular-scale adsorption mechanism of the antibiotic nalidixic acid (NAL) onto ferrihydrite and maghemite surfaces. High-surface area ferrihydrite and nano-sized maghemite were prepared as model adsorbents. This work provides a complete band assignment for protonated and deprotonated NAL to better describe in situ adsorption processes. In situ ATR-FTIR spectroscopy suggests that NAL mainly adsorbs on both iron oxides by a bidentate mode. Results also suggest that two sorption sites coexist on Maghemite surfaces leading to two sorption modes through the carboxylate group: bidentate chelate and bidentate bridging. The obtained results can contribute significantly towards molecular level understanding of antibiotics binding modes on iron oxides, a valuable piece of information to develop environmental remediation strategies.

Through the precipitation polymerization method, polyphosphazene microspheres (PHCPP) were prepared using hexachlorocyclotriphosphazene (HCCP) and phenolphthalein (PP) as precursors. Subsequently, PHCPP microspheres, which are enriched with abundant hydroxyl functional groups and named PHCPP-NaOH, were derived via an intramolecular ester ring-opening reaction under alkaline conditions. Their morphology, composition, and structure were thoroughly characterized using various techniques. Due to electrostatic attraction and hydrogen bonding between PHCPP-NaOH and dye molecules, PHCPP-NaOH exhibited a high adsorption capacity (481.25 mg g⁻¹) towards the cationic dye (methylene blue). The adsorption process can be described with both Langmuir and pseudo-second-order models, and this was spontaneous and favorable. DFT calculations corroborated the experimental findings and the adsorption models, thereby validating the analysis. The fabricated PHCPP-NaOH exhibits promising potential as an effective adsorbent for removing cationic dyes from aqueous solutions.