Xiao-Yang Yu

The development of materials for the remediation and monitoring of water environments remains a significant challenge in the field of environment and materials science. In this study, a nickel-based coordination polymer, [Ni(L)(H₂O)₃]_n·nH₂O (1), was synthesized employing 4,4′-(1H,1′H-[2,2′-biimidazole]-1,1′-diyl)dibenzoic acid (H₂L). Single-crystal X-ray diffraction analysis showed that L²⁻ ligands connect Ni²⁺ ions into 1D Z-shaped chains via two coordination modes. The chains are further assembled into a 3D supramolecular structure through hydrogen bonding interactions. The photocatalytic test showed that complex 1 could effectively degrade the organic dye methylene blue (MB). Under the conditions of catalyst dosage 5 mg, MB initial concentration 20 ppm and pH 7, the degradation efficiency reached 87.7% within 180 min. In addition, complex 1 can be used for the electrochemical detection of norfloxacin (NOR) by differential pulse voltammetry (DPV), exhibiting a linear response in the concentration range of 2–197 μM and the detection limit (LOD) of 1.74 μM. These results demonstrate that complex 1 has bifunctional properties of photocatalytic degradation of organic dyes and electrochemical sensing of antibiotic NOR, making it a promising candidate material for the synergistic treatment of complex pollutants.

A polyoxometalate-based metal–organic complex with the ability to treat pollutants in water was obtained under hydrothermal conditions, namely [Ni(H₂L)(HL)₂](PMo₁₂O₄₀)·3H₃O·4H₂O (1) (H₂L = 4,4′-(1H,1′H-[2,2′-biimidazole]-1,1′-diyl)dibenzoicacid). Structural analysis reveals that the [Ni(H₂L)(HL)₂] units are interconnected into a 2D layer via hydrogen bonds between adjacent carboxyl groups and water molecules of crystallization. [PMo₁₂O₄₀]³⁻ anions are embedded within the larger pores of the layer and are connected to the adjacent layers through hydrogen bonds, ultimately expanding the structure into a 3D supramolecular architecture. The intermolecular interactions were studied via Hirshfeld surface (HS) analysis. Electrochemical performance tests reveal that 1 exhibits electrocatalytic activity toward the oxidation and reduction of diverse pollutants in water, including NO₂⁻, Cr(VI), BrO₃⁻, Fe(III), and ascorbic acid (AA). Additionally, it can also serve as an amperometric sensor for the detection of BrO₃⁻ and Cr(VI). Photocatalytic studies reveal that compound 1 functions as a bifunctional photocatalyst, which not only achieves efficient degradation of organic dyes but also demonstrates remarkable reduction efficiency for toxic Cr(VI). Compound 1 demonstrates significant potential for practical water remediation applications.

The W₁₈O₄₉/[PEI/P₂W₁₈]₂₀ film with a unique bird-nest-like network structure exhibits excellent electrochromic energy storage capacity. The ECSC based on this film has a high area capacitance and retention rate, and the storage state is visualized.

Three new inorganic-organic hybrid compounds, (H₃DIBA)₂·SiMo₁₂O₄₀·H₂O (1), (H₃DIBA)₂·SiW₁₂O₄₀·H₂O (2), and [(H₂DIBA)(H₃DIBA)]·PMo₁₂O₄₀·2H₂O (3) (HDIBA = 3,5-di(1H-imidazol-1-yl)benzoic acid) were synthesized by the hydrothermal method. The structures were characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. These three compounds are all 3D supramolecular structures formed by Keggin-type polyoxometalate anions and HDIBA through intermolecular weak interactions, which have been studied via Hirshfeld surface analysis. The electrochemistry properties of 1 and 3 have been studied, including cyclic voltammetric behaviors and electrocatalytic properties. The study on the removal of organic dye pollutants in water showed that compounds 1 and 3 had an adsorption effect on cationic dye RhB, and the adsorption process conforms to the Langmuir isotherm model. Compound 2 can photocatalytically degrade cationic organic dyes RhB, MB, and CV, and the photocatalytic mechanism study indicates that h⁺ plays a major role in the photocatalytic process.