New Journal of Chemistry最新文献

Designing efficient and cost-effective nonprecious electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution still remains a significant challenge. Herein, we fabricated a three-dimensional (3D) transition bimetallic phosphate/reduced graphene oxide grown in situ on a nickel foam (NiCoP@rGO/NF) for the HER in alkaline media. NiCoP@rGO/NF exhibits a unique three-dimensional spherical nanostructure with a large specific surface area and short diffusion path, which are conducive to the transfer of electrons. NiCoP@rGO/NF requires an overpotential of only 94 mV at a current density of 10 mA cm⁻², with a low Tafel slope (39 mV dec⁻¹), and demonstrates excellent durability in 1.0 M KOH condition. Our work provides a new idea for designing high-performance HER electrocatalysts, which are highly needed in various practical applications.

The exploitation of photoelectrode materials with high-efficiency utilization of solar light, an outstanding separation property of photogenerated charges and a large surface area is extremely important yet significantly challenging. Herein, a three-dimensional array of reduced TiO₂ nanobelts with a disordered surface and abundant oxygen vacancies was successfully constructed for PEC water splitting. As expected, the reduced 3D-TiO₂ nanobelt array produced a photocurrent density of 0.96 mA cm⁻² at 0.22 V vs. Ag/AgCl with a faradaic efficiency of 100%, corresponding to 2.4 times enhancement compared with that of the pristine 3D-TiO₂ nanobelt array. Furthermore, IPCE was improved within both the UV and visible light regions. This enhancement originates primarily from the efficient utilization of UV-visible light as well as the promoted separation and transport of photogenerated charges induced by the cooperative effect of the disordered surface and oxygen vacancies. This research sheds new light on exploiting TiO₂ nanobelts for PEC applications.

A DBU-mediated synthesis of amides by using the readily available carbodiimides as nitrogen sources and unstrained 1,3-ketones as acyl sources has been developed. This reaction proceeds through the cleavage of two CN bonds of the carbodiimides, two C(CO)–C bonds of 1,3-diketones and the formation of two new C(CO)–N bonds, simultaneously.

In this research, a new and efficient nanocomposite composed of a heteropolyacid stabilized on mesoporous titanium oxide and graphitic carbon nitride was introduced. The prepared nanocomposite was analyzed and characterized using XRD, FE-SEM, EDX elemental mapping, Raman, TGA, TEM and BET techniques. An investigation of the three-component condensation reaction of aromatic aldehydes, 2-naphthol and urea was carried out using H₃PMo₁₁O₃₉@TiO₂@g-C₃N₄ as a nanocatalyst at 80 °C under solvent-free conditions. As a result of the synthesis of 1,3-oxazine derivatives, short reaction times (5–12 min), mild conditions, high product yields (85–95%), purity, easy preparation, compatibility with the environment, low cost, chemical stability and high selectivity were obtained. Furthermore, it is easy to recover the prepared nanocomposites through filtration, and they can be reused for at least five runs in the reaction without losing their catalytic activities.

Aristolochic acid (AA) has strong carcinogenicity, and it has been reported that the medicinal and edible plant Houttuynia cordata may contain AA. Among transition metals, nickel and iron have outstanding catalytic ability for nitro reduction. The multivalent NiFe₂O₄ (NFO), which effectively promotes the redox reaction, has become a promising electrochemical material. In this work, we innovatively used a one-pot hydrothermal method to prepare NFO in situ on the surface of carbon nanotubes. For the first time, the composite NiFe₂O₄@MWCNTs (NFO@CNTs) was utilized to build a sensitive electrochemical sensor for detecting AA. The NFO@CNTs/GCE exhibited strong electrochemical performance due to the synergistic effect of high catalytic activity of NFO and good conductivity of carbon nanotubes. Furthermore, in order to provide a basis for the safe use of Houttuynia cordata, the electrochemical senor was successfully applied to detect AA in Chinese herbal medicines, confirming its practicability in real samples. This work broadens the application of nickel ferrite, which is expected to be a new candidate material for sensors.

Copper(I) and silver(I) complexes have garnered significant interest as photoluminescent and electroluminescent emitters. Developing efficiently luminescent copper(I) and silver(I) complexes relies on the rational design of ligands, based on a deep understanding of the relationships between structure, excited states, and photophysical properties. Herein, a copper(I) complex and a silver(I) complex, namely Cu(Ac-phen)XP·BF₄ and Ag(Ac-phen)XP·BF₄, were synthesized based on a donor–acceptor–donor (D–A–D) type diimine ligand and a bisphosphine ligand. Cu(Ac-phen)XP·BF₄ and Ag(Ac-phen)XP·BF₄ in the solid state exhibit red and orange-yellow emission with photoluminescent quantum yields of 18% and 40%, and emission lifetimes of 1.2 μs and 7.8 μs, respectively. Theoretical and experimental investigations demonstrate that both complexes emit efficient thermally activated delayed fluorescence (TADF) from excited states dominated by intra-ligand charge transfer (ILCT) transitions. The ILCT emissive states are attributed to the stronger electron-donating ability of the A–D–A type ligand compared to the d¹⁰ copper and silver centers. The distinct metal coordination effects of the copper and silver centers lead to different levels of LUMO stabilization in the diimine ligand, resulting in different emissions for the copper(I) and silver(I) complexes.

The utilization of aliphatic diols as a substitute for epoxides in the reaction with CO₂ to produce cyclic carbonates offers a cost-effective and less hazardous synthesis route. This approach aligns with green chemistry principles and presents new strategies to combat climate change. This study primarily focuses on the innovative application of an alkaline ionic liquid in conjunction with a Brønsted acid for the catalytic synthesis of cyclic carbonates from CO₂ and aliphatic diols. Three alkaline ionic liquid catalysts [DBUH]PHY, [TBDH]PHY, and [DBUH]TBD were successfully synthesized using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and phenol as precursors. Their chemical structures and thermal properties were systematically characterized using Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (¹H-NMR), carbon nuclear magnetic resonance (¹³C-NMR), and thermogravimetric (TG) analysis. The catalytic performance of the three alkaline ionic liquids combined with various Brønsted acids (including sulfuric acid, phosphoric acid, and acetic acid) for the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO₂ was investigated. The results demonstrated that the combination of [DBUH]PHY with sulfuric acid (H₂SO₄) exhibited the best synergetic catalytic effect. Subsequently, the process parameters were optimized to study the effects of reaction temperature, pressure, time, and catalyst loading on catalytic performance. Under optimized conditions, the catalytic efficiency of [DBUH]PHY and sulfuric acid in the synthesis of cyclic carbonates from different aliphatic diols, including ethylene glycol, propylene glycol (1,2- and 1,3-), and butanediol (1,4-), was explored. This study successfully achieved the activation of aliphatic diols and CO₂ through cooperative catalysis of alkaline ionic liquids and Brønsted acids, providing an innovative catalytic system for research in this field.

Heat-resistant and low-sensitivity energetic materials are urgently needed in demanding environments, such as deep oil wells, space blasting, and hypersonic weapons. Herein, through the processes of substitution, reduction, cyclization, nitration, and ammoniation, two nitro groups and two amino groups were successfully introduced into a benzimidazole framework to prepare a new heat-resistant energetic material, 4,6-diamino-5,7-dinitro-1H-benzo[d]imidazole (DADNBI). Single crystal X-ray diffraction was executed to verify the structure of the compound. Crystal DADNBI belongs to the C2/c space group and monoclinic crystal system. The thermal stability of DADNBI was analyzed through differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and results showed that the decomposition temperature of DADNBI was 366 °C, which is higher than that of 2,4,6-trinitrotoluene (TNT) (T_d: 295 °C), hexanitrostilbene (HNS) (T_d: 318 °C), and 5,5′-bis(2,4,6-trinitrophenyl)-2,2′-bi(1,3,4-oxadiazole) (TKX-55) (T_d: 335 °C) and comparable to that of 1,3,5-tritamino-2,4,6-trinitrobenzene (TATB) (T_d: 360 °C). Non-isothermal thermal decomposition kinetics and Mayer bond pole calculations verified the excellent thermal stability of DADNBI from a theoretical perspective. The characteristic drop height (h_50%) of DADNBI is 305 cm. All these parameters of DADNBI far exceed those of the reported 5,7-dinitro-1H-benzo[d]imidazole (DNBI). This work offers important guidelines from both theoretical and experimental perspectives for designing and synthesizing new insensitive heat-resistant energetic materials.

In this study, a Zr based MOF chiral catalyst was synthesized, characterized, and then examined in the enantioselective Henry reactions. The process involved the synthesis of UiO-66-NH₂, followed by its functionalization with 2-chloroacetyl chloride. Subsequently, L-phenylglycine was immobilized on the functionalized MOF to prepare a chiral heterogeneous ligand. Finally, the prepared chiral ligand was complexed with Cu(CH₃CN)₄PF₆ to obtain the chiral heterogeneous catalyst. All of the synthesized materials were characterized using various methods including FT-IR, XRD, SEM, EDX, elemental mapping, and BET/BJH analysis. Evaluation of the catalytic activity of the prepared chiral heterogeneous catalyst under different conditions demonstrated that the best results can be achieved under solvent free green conditions at room temperature, producing excellent yields and low to moderate enantioselectivities. The heterogeneous catalyst was recovered and reused easily, maintaining activity over three consecutive cycles.

The construction of heat transfer channels based on highly thermally conductive fillers in a polymer matrix is important for improving the thermal conductivity of thermal management materials (TMMs). However, owing to the inhomogeneity of filler distribution and the limitation of the mechanical properties of polymers, it is a great challenge to achieve both high thermal conductivity and excellent mechanical properties. In this work, a simple air/water interfacial (AWI) assembly was implemented for the preparation of boron nitride–silver nanowires/polyvinyl alcohol (BN–Ag NWs/PVA) films. BN–Ag NW hybrid fillers were obtained through the ultrasonic treatment of amino-functionalized BN flakes with an Ag NW solution, followed by drying. BN–Ag NWs/PVA composite films were prepared via AWI assembly on the surface of a saturated sodium sulphate solution based on the salting-out effect. BN flakes tended to be oriented and aligned along the in-plane direction, and Ag NWs could bridge different BN flakes to form thermal conductivity pathways. The in-plane thermal conductivity of the BN–Ag NWs/PVA film was 1.24 W m⁻¹ K⁻¹ at a filler content of 25 wt%, which was about 4.8 times higher than that of a pure PVA film. Meanwhile, the tensile strength of the BN–Ag NWs/PVA film could reach 54.3 MPa owing to the regular distribution of hybrid fillers. The simultaneous improvement of thermal conductivity and mechanical properties was beneficial for the practical application of BN–Ag NWs/PVA films.