Novel divalent Co(II), Ni(II) and Zn(II) Schiff base complexes have been synthesized by reacting a prepared Schiff base (H₂L, 2-(ethoxycarbonyl-hydrazono)-pentanedioic acid) with metal salts. Ligand H₂L was prepared through condensation of α-ketoglutaric acid with ethyl carbazate. Solid solutions [Ni_1/3Co_2/3(HL)₂] and [Zn_1/3Co_2/3(HL)₂] were prepared by performing the reaction with stoichiometric proportions of metal ions. The crystal structures of metal (Co and Zn) and mixed metal (Ni–Co and Zn–Co) complexes were isomorphic and crystallized in a monoclinic system of space group C2/c. Interestingly, prepared solid solutions were employed as precursors for producing nanospinels such as nickel cobaltite (NiCo₂O₄) and zinc cobaltite (ZnCo₂O₄). As-synthesized spinel cobaltite nanoparticles (NPs) were characterized by Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HR-TEM) techniques. PXRD revealed a predominant spinel-type structure with a crystalline nature and high purity. Lattice parameters were calculated to be 8.1120 Å for NiCo₂O₄ and 8.1178 Å for ZnCo₂O₄. The morphology studies (by FESEM and HRTEM) revealed that the spinels were built by self-assembled aggregation of NPs with irregular shapes. Based on the TEM and HRTEM images, the mean sizes of the NPs synthesized by as-prepared solid solutions were 22–24 nm for NiCo₂O₄ and 16–18 nm for ZnCo₂O₄. In addition, photocatalytic degradation activity was evaluated using rhodamine dyes in visible light. Surprisingly, nanospinels employed as electrode materials showed a good specific capacitance C_sp of 115 F g⁻¹ (NiCo₂O₄), 177 F g⁻¹ (ZnCo₂O₄) at a 0.25 A g⁻¹ current density. Furthermore, the as-prepared nanospinels showed desirable stability in alkaline electrolyte with excellent cycling performance.

中文翻译：

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纳米尖晶石钴矿及其催化和电化学性质：轻松合成由α-酮戊二酸和氨基甲酸乙酯制备的席夫碱的金属（钴，镍和锌）和混合金属（钴-镍和钴-锌）配合物

通过使制备的席夫碱（H ₂ L，2-（乙氧基羰基-肼基）-戊二酸）与金属盐反应合成了新颖的二价Co（II），Ni（II）和Zn（II）席夫碱配合物。配位体H ₂ L的通过与肼基甲酸乙酯α酮戊二酸的缩合制备。固溶体[Ni _1/3 Co _2/3（HL）₂ ]和[Zn _1/3 Co _2/3（HL）₂通过以化学计量比例的金属离子进行反应来制备[]。在空间群C 2 / c的单斜晶系中，金属（钴和锌）和混合金属（镍钴和锌钴）配合物的晶体结构同构并结晶。有趣的是，制得的固体溶液作为前体用于生产nanospinels如镍钴（镍钴₂ Ò ₄）和锌钴矿（碳酸锌₂ Ò ₄）。通过傅立叶变换红外（FT-IR）光谱，粉末X射线衍射（PXRD），X射线光电子能谱（XPS），场发射扫描电子显微镜（FESEM）对合成后的尖晶石钴纳米颗粒（NPs）进行了表征和高分辨率透射电子显微镜（HR-TEM）技术。PXRD显示出主要的尖晶石型结构，具有晶体性质和高纯度。晶格参数分别计算为8.1120埃为镍钴₂ ö ₄和8.1178一种用于碳酸锌₂ ö ₄。形态学研究（通过FESEM和HRTEM）表明，尖晶石是由具有不规则形状的NP的自组装聚集所构建的。基于该TEM和HRTEM图像，由所制备的固体溶液中合成的纳米粒子的平均尺寸为为镍钴22-24纳米₂ ø ₄为碳酸锌和16-18纳米₂ Ò ₄。另外，使用若丹明染料在可见光下评估了光催化降解活性。令人惊讶地，用作电极材料的纳米尖晶石显示出良好的比电容C _sp为115 F g ^-1（NiCo ₂ O ₄），177 F g ^-1（ZnCo ₂ O _4）。）在0.25 A g ^-1的电流密度下。此外，所制备的纳米尖晶石在碱性电解质中显示出所需的稳定性，具有优异的循环性能。