Ammonia is an essential chemical feedstock; however, its conventional synthesis via the Haber-Bosch process is associated with high energy consumption and substantial carbon emissions. Developing green and efficient electrocatalytic routes for ammonia synthesis is therefore of significant importance. To overcome sluggish reaction kinetics and limited electron transfer, 26-faceted Cu₂O polyhedra were synthesized using a template-free chemical precipitation method, followed by the deposition of Ag particles onto the Cu₂O surface via photoreduction. This catalyst design optimizes the electronic structure, facilitates interfacial charge transfer, and enhances the intrinsic activity for converting key reaction intermediates (such as *NO₂ and *NH₂OH) into NH₃. As a result, the hydrogen evolution reaction and by-product formation are suppressed, leading to improved electrocatalytic performance for nitrate reduction to ammonia. Electrochemical evaluations demonstrate that Ag-Cu₂O exhibits excellent catalytic activity for the nitrate reduction reaction, achieving a Faradaic efficiency of up to 88%, which outperforms Au-Cu₂O and pristine Cu₂O, while generating lower amounts of the nitrite by-product and the competing hydrogen product. The catalyst maintains effective performance across a wide range of nitrate concentrations, supporting its potential applicability in nitrate wastewater treatment with varying pollutant levels. This study provides new insights into the rational design of high-performance and durable electrocatalysts for nitrate reduction and offers a valuable reference for advancing electrocatalytic technologies in wastewater treatment and green ammonia synthesis.

To achieve efficient utilization of the full solar spectrum and enhance the photocatalytic performance of cobalt tungstate (CoWO₄), one-dimensional CoWO₄ nanomaterials doped with rare-earth (RE) elements (Ce³⁺, Eu³⁺, Yb³⁺, and La³⁺) were synthesized using electrospinning technology. The structural, morphological, photocatalytic, and photothermal sterilization properties of the synthesized nanomaterials were systematically investigated. X-ray diffraction analysis revealed that all samples retained the monazite monoclinic structure of wolframite, with RE doping inducing lattice distortion. Scanning electron microscopy and transmission electron microscopy results demonstrated that doping increased the surface roughness of the nanotubes and generated a porous structure, thereby providing more active sites for reactions. Photocatalytic performance tests showed that 7% Ce-CoWO₄ achieved a degradation rate of 90.54% for ciprofloxacin under visible light within 140 min and 81.84% under near-infrared (NIR) light within 7 h. Electrochemical tests indicated that RE doping effectively reduced charge-transfer resistance and enhanced the photocurrent response. In terms of photothermal performance, 5% Yb-CoWO₄ increased the temperature of the liquid system to 65℃ within 360 s under NIR irradiation, demonstrating excellent photothermal conversion capability. Antimicrobial experiments confirmed that the re-doped samples exhibited significant photothermal sterilization effects against Escherichia coli under NIR irradiation. This study provides new insights into the development of efficient, multifunctional photocatalytic materials with full-spectrum response capabilities.

Melilite-structured compounds with the general formula ABC₃O₇—where A is an alkaline earth metal (e.g., Ca²⁺, Sr²⁺, or Ba²⁺), B is a trivalent rare-earth ion, and C is a trivalent main-group element (e.g., Ga³⁺ or Al³⁺)—represent an important class of inorganic functional materials. Owing to their stable crystal structure, tunable chemical composition, excellent physical and chemical stability, and multiple lattice sites available for activator ions, these materials have shown considerable potential in luminescence applications. This article provides a systematic review of recent advances in ion-doped ABC₃O₇-based luminescent materials. It highlights the characteristic features of the melilite-type crystal structure and presents a comprehensive summary of the luminescent properties, site occupancy behaviors, and concentration quenching effects of representative activator ions, including Eu³⁺, Tb³⁺, Dy³⁺, Mn²⁺, and Cr³⁺, within this host lattice. Additionally, the energy transfer mechanisms between sensitizers (e.g., Bi³⁺) and activator ions are thoroughly examined, and strategies for color tuning and performance enhancement via ion co-doping are discussed. Finally, current challenges and future research directions are outlined, providing theoretical insights and practical guidance for the rational design of high-performance melilite-structured luminescent materials.

Lead-based halide perovskite nanocrystals have attracted extensive attention due to their outstanding optoelectronic properties. However, their small Stokes shifts often lead to severe self-absorption, which greatly limit their luminescence efficiency and practical applications. Moreover, the inherent biological toxicity of lead poses irreversible risks to human health and the environment. To address these issues, this study synthesized lead-free Cs₃Cu₂X₅(X=Cl, Br, I) perovskite nanocrystals using a hot-injection method and systematically characterized their phase purity, compositions, and microstructures. Optical measurements, including fluorescence spectroscopy and temperature-dependent fluorescence lifetimes, revealed that the high photoluminescence quantum yield and large Stokes shifts of Cs₃Cu₂X₅ nanocrystals originate from their self-trapped exciton emission mechanism. To enhance their applicability, we further coated the nanocrystals with a SiO₂ shell, which significantly improved their dispersibility in aqueous media and their biocompatibility. Finally, using Escherichia coli as a model bacterium, the photo-induced antibacterial performance of the Cs₃Cu₂X₅@SiO₂ core-shell nanocrystals was evaluated through turbidity analysis and colony counting assays. This study revealed the physical origin of the outstanding luminescent properties of Cs₃Cu₂X₅ nanocrystals and demonstrated their potential as efficient and safe optical materials in biomedical applications.