New Journal of Chemistry最新文献

It is of great importance to prepare metal oxides with the assistance of biomass. In this work, we firstly synthesized a Cu₂O polyhedron/C composite via a facile one-step hydrothermal method using lignin as a reducing agent. This plant-based reducing agent is widely distributed, rich in resources, and renewable, and it has a low pyrolysis temperature. The Cu₂O polyhedron with an exposed (111) plane and oxidized carbon fibers in the composition exhibited excellent lithium-storage performance with high specific capacity, stable cycling, quick diffusion kinetics, and superior rate capability. This work will undoubtedly accelerate the development of advanced Li-ion batteries.

The global rise in antibiotic resistance underscores the urgent need for alternative antimicrobial strategies. One approach involves the conjugation of iron-chelating moieties to macromolecular scaffolds to disrupt bacterial iron homeostasis and inhibit cellular uptake mechanisms. In this work, the pre-chromophoric unit of the siderophore ferribactin served as the structural template for the development of antimicrobial polymer precursors. A series of L-tyrosine and L-DOPA-derived pre-chromophore analogues were synthesized and chemically modified to introduce polymerizable functionalities. These monomers were copolymerized with N-vinylpyrrolidone via reversible addition–fragmentation chain-transfer (RAFT) polymerization to afford well-defined, bifunctional copolymers. Antimicrobial testing of the monomers and polymers showed varying levels of activity, depending on the bacterial species.

Electrochemical urea synthesis from CO₂ and NO co-electrolysis (EUCN) offers a promising approach for simultaneously converting harmful NO/CO₂ emissions into value-added urea under ambient conditions. Herein, amorphous MnO₂ (a-MnO₂) with rich oxygen vacancies (OVs) is explored as a high-performance catalyst for EUCN, showing the exceptional faradaic efficiency of 36.69% and urea yield rate of 51.96 mmol h⁻¹ g⁻¹ in a membrane electrode assembly electrolyzer. Combined experimental and theoretical analyses reveal that the enhanced EUCN performance of a-MnO₂ originates from the critical role of low-coordinated Mn sites adjacent to OV (L-Mn_OV) in promoting NO activation and lowering the energy barrier for C–N coupling while inhibiting the competing side reactions, consequently leading to efficient and selective urea generation.

This study reports the controlled synthesis of ultrafine FeNi colloidal nanoparticles (2–5 nm) uniformly dispersed over a NiO/Fe₂O₃ matrix, developed as an efficient nanocatalyst for the reduction of 4-nitrophenol to 4-aminophenol. Comprehensive characterization was performed using XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), UV-Vis DRS (ultraviolet-visible diffuse reflectance spectroscopy), HRTEM (high-resolution transmission electron microscopy), and XPS (X-ray photoelectron spectroscopy). XRD and FTIR confirmed the coexistence of α-Fe₂O₃ and NiO phases, while UV-Vis DRS revealed distinct electronic transitions attributed to Fe and Ni species. TEM and HRTEM images demonstrated a uniform nanorod morphology with clear lattice fringes, and the SAED pattern verified the crystalline nature of the catalyst. The synergistic interaction between Fe and Ni was found to enhance catalytic performance, while computational studies provided mechanistic insight into the reduction pathway, supporting the observed high efficiency of the FeNi CNPs/NiO/Fe₂O₃ system.

Due to the polyoxygenated nature, hydrodeoxygenation (HDO) is generally employed to obtain bio-based chemicals from lignocellulosic biomass. Herein, a metal-free N and B co-doped porous carbon catalyst was prepared by a polymerization and carbonization strategy and applied to the catalytic transfer hydrodeoxygenation (CTHDO) of lignin-derived vanillin (VAN) to 2-methoxy-4-methylphenol (MMP). Among all the catalysts, N and B co-doped porous carbon (NSBCC-0.3, with 0.3% B content) showed the best performance, with a VAN conversion of 52.1% and a MMP selectivity of 68.6% at 240 °C under 1 MPa N₂ pressure in 2 h. Catalyst characterizations showed that B doping can lead to the formation of N–B pair structures, resulting in positively charged B sites and negatively charged adjunct N sites. The B sites with positive charges enhance the adsorption of CO from VAN, while adjunct N sites can capture the active H* from isopropanol. To gain insights into such effects, density functional theory (DFT) calculations were carried out. Seven possible N–B sites were constructed, and the VAN and H* adsorption energies on these sites were calculated. The optimal site configuration was 3-PyN-2-GaN-2; the highest valence state of B at this site was +2.01, and the VAN and H* adsorption energies were −0.3850 eV and −5.9782 eV, respectively. NH₃-TPD and CO₂-TPD analyses demonstrated that boron doping significantly modulates the acid–base site concentration, creating a favorable microenvironment for the CTHDO reaction. This work is expected to provide an efficient and environmentally friendly method for the preparation of heteroatom-doped carbon-based catalysts for biomass conversion processes.

Maintaining the stability and efficiency of pollutant degradation across a wide pH range remains a critical challenge for the practical application of advanced oxidation processes (AOPs). In this study, a heterogeneous catalyst was developed by integrating acidic-active ZrO₂ with multivalent MnO_x to activate persulfate for the efficient degradation of a typical dye, Acid Orange II. Benefiting from the amphoteric nature of ZrO₂, the reaction environment maintains pH stability under varying conditions, thereby preventing changes in the surface charge state of the catalyst caused by pH fluctuations. The ZrO₂/MnO₂ composite exhibited excellent performance over a broad pH range (3–9), along with a significantly reduced manganese leaching ratio. Moreover, the presence of ZrO₂ promoted the formation of oxygen vacancies, enhancing the activity of manganese species and thereby improving the catalytic performance and reusability of the composite. The acidic microenvironment provided by ZrO₂ facilitated the generation and activity of sulfate radicals (SO₄˙⁻), resulting in a markedly improved total organic carbon (TOC) removal efficiency. This work presents a pH-adaptive catalytic system for persulfate activation through microenvironmental modulation, demonstrating promising potential for practical applications in AOP-based water treatment.

A series of multivariate fluorinated covalent organic frameworks (COF-Tfmbx, x = 0, 33, 50, 67, 100) are designed through strategic integration of Co²⁺ centers and fluorine-containing units to simultaneously enhance conductivity and hydrophilicity for superior oxygen evolution reaction (OER) performance. In particular, Co-COF-Tfmb₅₀ exhibits exceptional electrocatalytic oxygen evolution reaction (OER) performance, achieving a mere 362 mV overpotential at 10 mA cm⁻², a low Tafel slope of 53 mV dec⁻¹, and outstanding stability (93% current retention after 24 h), attributed to synergistic effects of: fluorine-enabled charge transfer, hydrophilic interface optimization and hierarchical pore architecture facilitating mass transport. These results demonstrate an effective approach to designing and constructing novel COF-based OER catalysts.

Cobalt sulfide holds great promise for use in dye-sensitized solar cells (DSSCs) and supercapacitors due to its versatile properties. However, its practical application is often constrained by drawbacks such as low electrical conductivity, suboptimal nanostructuring, and limited long-term stability. This work addresses these limitations by introducing neodymium (Nd) doping into nitrogen-enriched cobalt/cobalt sulfide (Nd–N–Co/CoS). This enhances the structural and electronic properties by inducing lattice distortion and generating beneficial defects. Herein, Nd–N–Co/CoS samples are synthesized with varying neodymium doping levels (2%, 4%, and 6%) and used as counter electrodes in DSSCs. Among these, the 4% Nd-doped sample demonstrated superior electrocatalytic performance, showing the lowest charge transfer resistance in symmetric cells and achieving a power conversion efficiency (PCE) of 6.9%, which exceeds the efficiency (6.5%) of conventional platinum (Pt) electrodes under standard air-mass 1.0 global (AM 1.0G) illumination. Furthermore, symmetric supercapacitors were fabricated with the 4% Nd–N–Co/CoS electrode, which delivered a specific capacitance of 66.35 F g⁻¹, an energy density of 23.60 Wh kg⁻¹, and a power density of 1600 W kg⁻¹ at a specific current of 1 A g⁻¹. It also maintained a cycling stability of 94.51% and a Coulombic efficiency of 97.03% after 2000 cycles at 5 A g⁻¹, outperforming the undoped electrode. These findings highlight a promising approach for developing efficient electrode materials for next-generation energy conversion and storage technologies.

Ternary spinel-type transition metal sulphides like MnNi₂S₄ are promising supercapacitor electrodes due to their high theoretical capacitance and redox activity. However, the significance of sulfur precursor selection on the structural and electrochemical behaviours of MnNi₂S₄ remains under investigation. In this work, MnNi₂S₄ nanostructures were developed utilizing three sulfur sources: thioacetamide, sodium sulphide, and thiourea, to explore their impact on material characteristics and electrochemical performance. XRD confirmed the formation of the spinel MnNi₂S₄ phase for all samples, with the thioacetamide-derived material exhibiting the highest crystallinity. Raman spectroscopy revealed enhanced lattice ordering in the same sample, as evidenced by stronger vibrational peaks. However, BET surface area analysis showed that sodium sulphide and thiourea-based samples had larger surface areas, and FE-SEM and TEM analyses demonstrated that the thioacetamide-derived sample had a more favourable interconnected nanostructure. Electrochemical measurements, including CV, GCD, and EIS, established that the thioacetamide-based electrode provided an excellent electrochemical performance, as evidenced by the highest C_s of 2477.77 F g⁻¹ at 1 A g⁻¹, and improved rate capability with capacitance retention of 95.09% over 5000 cycles. These findings highlight the importance of precursor chemistry to optimize MnNi₂S₄ for energy storage applications, and they validate thioacetamide as a superior sulfur source for supercapacitor electrode development.

The development of highly effective and stable bifunctional electrocatalysts is crucial for achieving industrial green hydrogen generation in the water splitting field. Herein, a NiSn@NiMn–LDH heterostructured electrocatalyst based on interface engineering was fabricated by a two-step hydrothermal technique with Ti mesh (TM) as the SI. The NiSn@NiMn–LDH/TM heterostructured electrocatalyst exhibited excellent electrocatalytic activity in an alkaline electrolyte with the small overpotentials of 300.2 mV at 10 mA cm⁻² and 202.6 mV at 10 mA cm⁻² for the OER and HER, respectively. Moreover, there was no significant increase/decrease in the potential after a 50 h stability experiment at 30 mA cm⁻² toward the OER and HER, indicating that NiSn@NiMn–LDH/TM possessed outstanding catalytic stability as a bifunctional electrocatalyst. The exceptional electrocatalytic properties were caused by the electronic transformation at the interface between NiSn and NiMn–LDH, which originated from the generation of a heterogeneous structure, as well as the optimization of the interfacial electronic structure. The work can be reasonably used for the design and development of transition metal-based electrocatalysts, realizing the industrial application of hydrogen generation by water splitting.