New Journal of Chemistry最新文献

The oxidation of glycerol to dihydroxyacetone (DHA) represents an efficient and economical process route. Although preparing Au/CuO catalysts from plant constituents has emerged as a novel approach for synthesizing biocompatible products, the complexity of plant constituents means that the active components still need to be clarified, making it challenging to control catalytic activity. In this study, we effectively separated and identified the active components of Syringa oblata Lindl. (SoL) leaf using column chromatography, and synthesized a series of Au/CuO catalysts from the different separated samples. Glycerol catalytic evaluation experiments showed that the S3 fraction, mainly consisting of phenolic substances, exhibited the highest catalytic activity, with a glycerol conversion rate of 86.6% and DHA selectivity of 82.0%, exceeding the activity of most current catalysts. A series of experiments and characterizations demonstrated the differences in reducibility and protective ability among the separated samples, and the preparation and glycerol reaction conditions for optimal performance are systematically optimized. This work provides in-depth insights into the preparation of catalysts using plant-based methods.

Both the use of renewable natural sources to prepare catalytic materials and the Meerwein–Ponndorf–Verley (MPV) reduction of carbonyl compounds are very attractive topics in catalysis. Neohesperidin (NES) with rich oxygen-containing groups can bind to various metal ions. In this work, NES has been used as the ligand to coordinate Zr(IV) for the synthesis of a porous coordination polymer (Zr-NES). Various characterization studies demonstrated the formation of robust porous inorganic–organic frameworks and strong Lewis acid–base sites in Zr-NES. Due to the presence of coordinatively unsaturated Zr sites, Zr-NES had highly active Lewis acid sites, so it can efficiently catalyze the hydrogenation of 5-hydroxymethylfurfural (HMF) to prepare 2,5-bis-(hydroxymethyl)furan (BHMF). After 2 h at a mild temperature of 120 °C, a BHMF yield of 99.0% with turnover frequency (TOF) of 8.5 h⁻¹ could be obtained. This robust bifunctional acid–base Zr-NES was also demonstrated to be effective in one-step reductive etherification of 5-HMF to 5-[(1-methylethoxy)methyl]-2-furanmethanol (MEFA), a potential biomass-derived fuel additive, with 90% yield. Kinetic studies revealed that the activation energy for CTH of 5-HMF was 44.73 kJ mol⁻¹, accounting for the high reaction rate. Due to the strong interactions between Zr⁴⁺ and oxygen-containing groups, Zr-NES was highly stable and could be reused without a significant decline in activity.

Here we report the synthesis of series of bipyridine-based porous polymers as macroligands for molecular copper complexes. The resulting Cu@N-POP solids efficiently catalyze the dehydrogenative N–N coupling of di-p-tolylamine into the corresponding hydrazine using oxygen as the oxidant. The heterogenization of the Cu-based catalyst within porous macroligands improved the catalytic activity with regard to previously reported Cu-based molecular homogeneous systems. Increasing the availability of the bipyridine sites to Cu coordination led to enhanced catalytic performances.

Herein, a heterostructured design strategy involving Ag nanoparticles (Ag NPs) stabilized with 5-(2-mercaptoethyl)tetrazole and immobilized on titania nanotubes for the oxygen reduction reaction (ORR) is reported. Bare titania nanotubular layers were annealed in air (TNT) or in a hydrogen atmosphere (hTNT), and their composites with tetrazole-stabilized Ag NPs (tz-Ag NPs) were evaluated for their ORR performance in alkaline media. The activity of the tz-Ag NP/TNT composites was shown to correlate with TNT doping level, which can be controlled by varying the annealing conditions. In all cases, the tz-Ag NP/hTNT composite shows more positive ORR onset and half-wave potentials (E_1/2) than the tz-Ag NP/TNT composite. An increase in tz-Ag NP loading onto the TNT and hTNT matrix leads to a decrease in the overpotential of O₂ reduction. The hTNT electrocatalyst loaded with a high amount of tz-Ag NPs (24 μg cm⁻²) exhibits superior ORR activity over a bare Ag electrode in terms of ORR onset and half-wave potentials. Ag NPs stabilized with tetrazole demonstrate an improved ORR performance in alkaline media compared to Ag NPs capped with citrate. The TNT electrodes loaded with tz-Ag NPs have shown high electrocatalytic activity toward the ORR indicating their suitability as cathode materials in alkaline fuel cells.

Cationic acridine dyes acted as a stabilizer for glucose oxidase adsorbed on a pencil graphite electrode and enhanced mediated bioelectrocatalysis for glucose oxidation. The order of the magnitude of the bioelectrocatalytic current was consistent with the binding constants estimated by fluorescence quenching and the binding energies estimated by docking simulation.

Selenization of ZrO₂ can be easily performed by stirring commercially available ZrO₂ in an in situ prepared NaHSe solution. The produced material Se@/ZrO₂ could catalyse oxidative alkene degradation reactions, which are key transformations in the industry. Control experiments confirmed that selenium loaded onto ZrO₂ endowed it with good catalytic activity for oxidation reactions. In comparison with the density of other selenized catalytic materials such as Se/C, selenized silica and selenized polylactic acid, the density of Se@ZrO₂ is higher. This feature makes it easy to precipitate from the reaction solution, facilitating its convenient recovery and reutilization.

Perovskite oxides are promising candidates for diverse applications due to their versatile physical and chemical properties. However, their structural and compositional flexibility significantly delay the traditional methods of screening formable and thermodynamically stable perovskite oxides. Single-label machine learning methods have been extensively used to solve this challenge, but these often result in the misselection of unstable perovskite oxides by formability prediction models and non-formable perovskite oxides by stability prediction models. Here, multi-label classification (MLC) methods are employed to simultaneously screen for both formable and stable perovskite oxides. We investigate the label dependency of formability and stability labels, finding significant unconditional dependency but little conditional dependency. Using a recursive feature addition method, 10 features are selected from an initial set of 159. SHapley Additive exPlanations (SHAP) analysis reveals that the atomic weight of B-site elements and the ionic radii ratio of the A-site to the B-site cations are the most important features. Among the eight MLC methods evaluated, the classifier chains (CC) model outperforms its counterparts. An optimized CC model achieves outstanding performance with a subset accuracy of 0.932 and a Hamming loss of 0.0342. This model is further generalized on 2226 virtual perovskite combinations, identifying 42 formable and stable perovskite oxides for future investigation. This work presents an effective approach for screening potential perovskite oxides, which can be further extended to other fields that involve predicting multiple properties concurrently.

A CuI@UiO-67-bpy (MOF II) catalyst was successfully synthesized by immobilizing a small amount of CuI onto the zirconium-based MOF (UiO-67-bpy, MOF I). Copper-doped CuI@UiO-67-bpy has an isostructural nature with the parent UiO-67 framework and a large surface area of approximately 1285 m² g⁻¹. Moreover, the material was thoroughly characterized using SEM, PXRD, TGA, FTIR, and XPS methods. The as-synthesized CuI@UiO-67-bpy catalyst can be an efficient heterogeneous catalyst for promoting C–H arylation of 1,3,4-oxadiazoles with aryl iodides and benzoxazoles or benzothiazoles with diaryliodonium salts. Furthermore, the catalyst was recoverable and reusable, maintaining a high catalytic activity even after three cycles. The combination of the advantages of both homogeneous molecular CuI catalysts and solid MOF structures in this system may bring new opportunities for the development of highly active heterogeneous copper catalysts for a variety of Cu-catalyzed transformations.

The excellent anti-interference ability of near-infrared (NIR) fluorescent materials derived from long-wavelength emission has made them one of the most fascinating fluorescence probes. In this work, gold nanoclusters stabilized with glutathione (GSH-AuNCs) were prepared and exhibited excellent NIR fluorescence at 806 nm, indicating their potential as excellent fluorescence probes. It is gratifying that S²⁻ could be sensitively and rapidly recognized through the “turn-off” strategy of NIR fluorescence of AuNCs. It is speculated that the quenching was due to the aggregation-caused quenching (ACQ) phenomenon. The combination of a longer wavelength emission of 806 nm and the strong binding ability of Au and S endowed the constructed sensing system with outstanding sensitivity and selectivity. A good linear relationship for the detection of S²⁻ was obtained in the range of 0–23.75 μM, with a limit of detection (LOD) of 14.67 nM (S/N = 3). This NIR fluorescence probe was successfully used for the detection of S²⁻ in real samples with satisfactory results.

Alpha-fetoprotein (AFP) is a characteristic marker of liver cancer, and its accurate detection is of great significance for the early detection of liver cancer. This study utilizes visible light as the excitation light source, employs electrochemical measurement, and incorporates the AFP aptamer as the biorecognition element to construct a photoelectrochemical (PEC) biosensor for the highly sensitive detection of AFP. A Z-scheme heterostructure is constructed via a two-step hydrothermal method, and CdS nanoparticles are anchored on TiO₂NRA and BiOI nanosheets with high specific surface areas. The photocurrent response of the BiOI/CdS/TiO₂NRA composite material is 4.5 times that of TiO₂NRA. By analyzing the energy band positions, the electron transfer mechanisms of Z-scheme heterojunctions in CdS/TiO₂NRA and BiOI/CdS photoactive materials were elucidated. Subsequently, the AFP aptamer was immobilized on the base electrode surface via the CN structure to fabricate a self-supporting sensing platform. The PEC biosensor demonstrates excellent detection performance within the linear range of 1 nM ∼ 250 nM, exhibiting high selectivity and the detection limit is 0.59 nM (S/N = 3). It has been effectively utilized for the detection of AFP in blood, providing a practical method for early detection and prevention of liver cancer, and also offering new insights for the design of other similar characteristic marker biosensors.