Journal of Sol-Gel Science and Technology最新文献_第6页

Collating the structural, vibrational, and photocatalysis properties of LaFeO3 rare-earth orthoferrite nanoparticles synthesized by the sol-gel method

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-11-09 DOI: 10.1007/s10971-024-06602-7

N. Manohar Reddy, D. Kothandan, Poli Reddy V, Simhadri Raju Juvvala, M. Gnana Kiran, Kodanda Rama Rao Chebattina, Uma Chaithanya Pathem, Shaik Jaheer Basha, Thiriveedhi Narendrudu, A. Kalpana

To synthesize the rare earth orthoferrite ({LaFe}{O}_{3}) nanopowder, a perovskite, a sol-gel technique was employed. The resulting particles were characterized using SEM, XRD, and UV-visible absorption spectroscopy. The perovskite structure of ({LaFe}{O}_{3}) (with La having an ionic radius of 1.36 Å) exhibits internal deformation due to the large ionic radii of the elements occupying the A-site. This deformation affects several of its desirable properties. Notably, there is a reduction in lattice parameters and an increase in octahedral distortion. Deviations in the Raman modes can indicate spin-phonon coupling in ({LaFe}{O}_{3}) additionally, increased crystalline distortions can hinder the spin-lattice interactions, leading to adverse effects.The particles were found to be uniformly spherical, with an average size of 80 nm. The optical energy band gap of ({LaFe}{O}_{3}) at the nanoscale was measured to be 2.1 eV. This structure was further confirmed through optical absorbance and Raman spectroscopy measurements, aided by spin-phonon coupling. The optical characteristics exhibit intriguing variations that correlate with the expected photocatalytic activities. The photocatalytic activity of ({LaFe}{O}_{3}) nanoparticles was evaluated through the UV degradation of various organic dyes, including acid fuchsine (AF), methyl orange (MO), rhodamine B (RhB), and methylene blue (MB). Notably, the dyes underwent substantial photocatalytic degradation when exposed to visible light.

Graphical Abstract

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引用次数: 0

Efficient and rapid sunlight-driven photocatalytic degradation of methylene blue dye using multiferroic BiFeO3 nanoparticles

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-11-06 DOI: 10.1007/s10971-024-06607-2

Madhu Verma, Ajay Kumar, Vijay Kumar Thakur, Akanksha Maurya, Sachin Kumar, Saurabh Singh, Simant Kumar Srivastav

The current investigation presents a facile and cost-effective sol-gel approach for the synthesis of phase-pure multiferroic bismuth ferrite (BiFeO₃) nanoparticles (BFO NPs) by using propylene glycol as a complexing agent, intended for use as a photocatalyst to efficiently degrade organic dyes in aqueous solutions under natural sunlight. Characterization techniques, including thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), elucidated a plausible reaction pathway for the formation of phase-pure BFO NPs. Rietveld refinement of the XRD data, in conjunction with transmission electron microscopy (TEM) and Raman spectroscopy, confirmed the synthesis of single-phase BFO NPs at 400 °C, displaying a space group of R3c and an average crystallite size of 25 nm. UV–visible diffuse reflectance spectroscopy revealed an absorption cut-off wavelength near 590 nm, corresponding to a band gap of 2.08 eV, indicating the capability of BFO NPs to absorb visible light within the 400–590 nm range. BFO NPs have shown efficient and rapid photocatalytic degradation of methylene blue (MB) in acidic, neutral, and basic pH conditions under natural sunlight. This is attributed to the intrinsic ferroelectric and ferromagnetic ordering present in synthesized BFO NPs which facilitates the separation and migration of photoinduced charges through band bending phenomena at the interface.

Graphical Abstract

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引用次数: 0

Preparation of SiO2 aerogel by water glass: effect of different sodium removal methods on aerogel properties 水玻璃法制备SiO2气凝胶：不同除钠方法对气凝胶性能的影响

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-11-02 DOI: 10.1007/s10971-024-06413-w

Wei Sun, Lu Yu, Jikai Su, Ruixiang Liu, Xuemei Yan, Dong Su, Pengyu Zhang, Xiaolei Li

Removal of Na⁺ is a very important step in the SiO₂ aerogel preparation using water glass as precursor, which has a significant effect on the structure and properties of aerogel. In this study, three methods (Solution-crystallization, Water washing, and Ion exchange) were used to remove Na⁺ from the system and investigated the effects of different methods on the aerogel properties. The results show that all three aerogels have low bulk density (<0.075 g/cm³), low thermal conductivity (≤0.015 W/(m·K)), and well hydrophobicity (θ ≥ 137°). Among them, Na⁺ exists in the sol in the sodium removal process by water washing and effects the uniformity of gel network. The samples for sodium removal by solution-crystallization show better hydrophobicity and poorer high-temperature stability, which is related to the presence of abundant hydrophobic groups (Si-OC₂H₅) on the gel surface. The microstructure and the pore size distribution of the aerogels prepared by ion exchange are uniform, which makes them have optimal comprehensive performance. The mechanism of solution-crystallization effect in the process of sodium removal was explored, providing a workable idea for low-cost preparation of SiO₂ aerogel.

Graphical Abstract

在以水玻璃为前驱体制备SiO2气凝胶的过程中，Na+的去除是一个非常重要的步骤，它对气凝胶的结构和性能有着重要的影响。本研究采用溶液结晶、水洗和离子交换三种方法去除体系中的Na+，并研究了不同方法对气凝胶性能的影响。结果表明，三种气凝胶均具有低堆积密度（<0.075 g/cm3）、低导热系数（≤0.015 W/(m·K)）和良好的疏水性（θ≥137°）。其中，Na+在水洗除钠过程中存在于溶胶中，影响凝胶网络的均匀性。溶液结晶法脱钠样品的疏水性较好，高温稳定性较差，这与凝胶表面存在丰富的疏水基（Si-OC2H5）有关。离子交换法制备的气凝胶的微观结构和孔径分布均匀，具有最佳的综合性能。探讨了除钠过程中溶液结晶效应的机理，为低成本制备SiO2气凝胶提供了可行思路。图形抽象

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引用次数: 0

Synthesis and characterization of MoO3: application to the photo production of oxygen under visible light MoO3的合成与表征：在可见光下光制氧中的应用

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-11-02 DOI: 10.1007/s10971-024-06589-1

Nesrine Koriche, Moussa Abbas, Mohamed Trari

One of the most striking features of molybdenum oxide is the versatility of its catalytic properties, which are determined by the valence states of molybdenum and its coordination. It may be anticipated that MoO₃ surface must contain catalytic sites which are active in different types of elementary steps. MoO₃ was successfully synthesized by hydrothermal route at 400 °C, acquiring n-type conduction, due to oxygen deficiency. The single phase, elucidated by X-ray diffraction, crystallizes in an orthorhombic unit cell (Space Group (SG) Pbnm, N° 62) with a crystallite size of 12 nm. MoO₃ is a direct band gap semiconductor with a forbidden band value of 2.93 eV where the electrical conduction occurs by low polaron hopping between mixed valences Mo^+6/+5 with an activation energy of 0.14 eV. The thermo-power indicates n-type conduction, and confirmed by the capacitance-potential measurement; the latter gives an electrons density of 1.87 × 10²⁰/cm³and a mobility of 1.77 × 10⁻⁶ m²/V.s. The flat band potential V_fb (0.11 V_SCE) is determined from the capacitance measurement. The physical and chemical characterizations are correlated for the construction of the potential diagram in order to assess the photo electrochemical properties of MoO₃ for the oxygen evolution. The valence band, is located above the O₂/H₂O potential ( ~ 1.3 V_SCE), allowing O₂ evolution upon visible light and the oxide is photocathodically protected against corrosion. An evolution rate of 0.13 mL/(mg. h) is obtained within 20 min. at optimal conditions (100 mg of catalyst and 50 °C).

钼氧化物最显著的特点之一是其催化性能的多功能性，这是由钼的价态及其配位决定的。可以预见，MoO3表面一定含有在不同类型的基本步骤中具有活性的催化位点。在400℃条件下，通过水热法成功合成了MoO3，由于缺氧，获得了n型导电。经x射线衍射证实，单相晶化在正交晶胞（Space Group (SG) pnm, N°62）中，晶粒尺寸为12 nm。MoO3是一种直接带隙半导体，禁带值为2.93 eV，通过Mo+6/+5混合价之间的低极化子跳变发生导电，活化能为0.14 eV。热功率为n型导通，经容电位测量证实；后者的电子密度为1.87 × 1020/cm3，迁移率为1.77 × 10−6 m2/V.s。平带电位Vfb （0.11 VSCE）由电容测量确定。将MoO3的物理和化学表征相关联，构建电位图，以评价MoO3在析氧过程中的光电电化学性能。价带位于O2/H2O电位（~ 1.3 VSCE）之上，允许O2在可见光下析出，并且氧化物具有光电阴极保护，防止腐蚀。进化速率为0.13 mL/(mg)。H)在20min内得到。在最佳条件下（100mg催化剂和50°C）。

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引用次数: 0

Tailoring the morphological and optical properties of monodisperse silica 调整单分散二氧化硅的形态和光学性质

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-11-01 DOI: 10.1007/s10971-024-06604-5

Anjali Saini, Harshvardhan Negi, Sanjay K. Srivastava, Prathap Pathi, Rimjhim Yadav, Mrinal Dutta

Monodisperse silica of sizes from 0.67 µm to 3.2 µm was synthesized by a low-cost semi-batch technique free from the use of any stabilizer, porogen or surfactant. The effect of precursor (tetraethyl orthosilicate), hydrolyzing agent and catalyst concentration variation on the size, morphology, size distribution and optical properties of silica particles was studied. TEM observation and N₂ adsorption-desorption studies showed the existence of a thin porous shell layer covering the outer surface of these particles. Absorption in the UV-Vis range confirmed that E’ and oxygen-deficiency centers (ODCs) prevailed. The observed broad photoluminescence including the UV, blue, green and red regions of the spectrum were attributed to the presence of ODCs, self-trapped excitons, hydrogen-related defects and non-bridging-oxygen hole centers respectively. A two-photon guided relaxation of free exciton was found to be a prominent cause of observed luminescence.

Graphical Abstract

采用低成本半批工艺合成了粒径为0.67µm ~ 3.2µm的单分散二氧化硅，不使用任何稳定剂、破孔剂或表面活性剂。研究了前驱体（正硅酸四乙酯）、水解剂和催化剂浓度的变化对二氧化硅颗粒尺寸、形貌、尺寸分布和光学性质的影响。TEM观察和N2吸附-解吸研究表明，这些颗粒的外表面存在一层薄薄的多孔壳层。紫外-可见光谱范围内的吸收证实了E′和缺氧中心（ODCs）的存在。在紫外区、蓝区、绿区和红区观察到的广谱光致发光分别是由于ODCs、自捕获激子、氢相关缺陷和非桥接氧空穴中心的存在。发现双光子引导的自由激子弛豫是观测到发光的主要原因。图形抽象

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引用次数: 0

Microwave absorption and magnetic properties of LiZnMn ferrites doped with Mg 掺Mg的LiZnMn铁氧体的微波吸收和磁性能

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-10-31 DOI: 10.1007/s10971-024-06594-4

Xueyun Zhou, Jun Wang, Dongsheng Yao

Ferrite has been extensively studied due to its wide range of applications. In present work, Li_0.4-0.5xZn_0.2Mn_0.1Mg_x-0.1Fe_2.4-0.5xO₄ (x = 0.1, 0.15, 0.2, 0.25, 0.3) were synthesized by sol-gel auto-combustion method. X-ray diffraction and infrared spectroscopy confirmed the formation of a cubic spinel structure. The lattice constant was found to increase with higher x values, while density, grain size and microstrain decreased correspondingly. The saturation magnetization and coercivity showed slight decreases after Mg doping, whereas the initial permeability slightly increased. The Curie temperature declined from 433 °C at x = 0.1 to 395 °C at x = 0.3. Mg doping also reduced the optimal matching thickness of microwave-absorbing materials to 3 mm. Mg-LiZnMn absorber is lighter in weight than LiZnMn. Notably, the sample with x = 0.15 exhibited excellent absorption characteristics from 8.2 GHz to 13.1 GHz, with a reflection loss (RL) of −32 dB. These findings suggest that an appropriate concentration of Mg doping can enhance the impedance matching of the materials, thereby improving their microwave absorption performance.

Graphical Abstract

Adding Mg in LiZnMn ferries can improves the initial permeability (μ_i) and microwave absorption performance.

铁氧体因其广泛的应用而受到广泛的研究。本文采用溶胶-凝胶自燃烧法合成了Li0.4-0.5xZn0.2Mn0.1Mgx-0.1Fe2.4-0.5xO4 （x = 0.1, 0.15, 0.2, 0.25, 0.3）。x射线衍射和红外光谱证实了立方尖晶石结构的形成。晶格常数随x值的增大而增大，而密度、晶粒尺寸和微应变则相应减小。Mg掺杂后，饱和磁化强度和矫顽力略有降低，初始磁导率略有提高。居里温度从x = 0.1时的433℃下降到x = 0.3时的395℃。Mg的掺杂也使吸波材料的最佳匹配厚度减小到3 mm。Mg-LiZnMn吸收体的重量比LiZnMn轻。值得注意的是，x = 0.15的样品在8.2 GHz至13.1 GHz范围内具有良好的吸收特性，反射损耗（RL）为−32 dB。这些结果表明，适当浓度的Mg掺杂可以增强材料的阻抗匹配，从而提高材料的微波吸收性能。摘要在lizznmn轮渡中加入Mg可以提高初始磁导率（μi）和微波吸收性能。

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引用次数: 0

Effect of Gd doping on the microstructure and electrical characteristics of Maghemite (γ-Fe₂O₃) ceramics Gd掺杂对磁赤铁矿（γ-Fe₂O₃）陶瓷微观结构和电特性的影响

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-10-30 DOI: 10.1007/s10971-024-06598-0

Ramzi Dhahri, Majdi Benamara, Souhir Bouzidi, Sana Ben Moussa, Abdullah Yahya Abdullah Alzahrani, Kais Iben Nassar, Nassim Zahmouli, Elkenany Brens Elkenany, A. M. Al-Syadi

This paper presents a novel study on the microstructure and electrical properties of gadolinium (Gd) doped maghemite (γ-Fe₂O₃) nanoparticles, emphasizing their significance for advanced applications in efficient materials. X-ray diffraction analysis confirmed that both pure and doped samples crystallized in a cubic structure (P4₃32 space group) with high purity. Gd doping significantly increased crystallite size and altered particle morphology, as shown by transmission electron microscopy (TEM), which revealed larger nanoparticles with cubic shapes. Thermal analysis (TGA and DTG) indicated that higher Gd concentrations enhanced thermal instability, affecting structural integrity. FTIR spectra showed shifts in Fe-O bond vibrations, suggesting lattice distortions and increased disorder. BET measurements indicated that higher Gd doping led to greater mesoporosity and surface area, countering expectations of densification. Electrical conductivity and impedance studies revealed two distinct regions: a constant conductivity at low frequencies and an exponential increase at high frequencies, attributed to small polaron hopping. Activation energy values below 200 meV support this mechanism. Gd doping decreased overall conductivity due to disrupted atomic arrangements, increased electron scattering, and modifications in the electronic band structure. Complex impedance spectroscopy illustrated higher real impedance values for doped samples, with increased Gd concentration leading to enhanced impedance. These findings elucidate the impact of Gd on the electrical properties of maghemite nanoparticles and highlight their importance in meeting the growing demands for highly efficient technologies in energy storage and electronic devices.

Graphical Abstract

本文对钆（Gd）掺杂磁赤铁矿（γ-Fe₂O₃）纳米颗粒的微观结构和电学性质进行了新的研究，强调了它们在高效材料中的先进应用意义。x射线衍射分析证实，纯样品和掺杂样品均以立方结构（P4332空间群）结晶，纯度高。透射电子显微镜（TEM）显示，Gd的掺杂显著增加了晶体尺寸，改变了颗粒形态，显示出更大的立方形状的纳米颗粒。热分析（TGA和DTG）表明，较高的Gd浓度增强了热不稳定性，影响了结构的完整性。FTIR光谱显示Fe-O键振动发生了变化，表明晶格畸变和无序性增加。BET测量表明，较高的Gd掺杂导致更大的介孔率和表面积，与致密化的预期相反。电导率和阻抗研究揭示了两个不同的区域：低频恒定的电导率和高频指数增长，归因于小极化子跳变。低于200兆电子伏的活化能值支持这一机制。由于原子排列被打乱，电子散射增加，电子能带结构改变，Gd掺杂降低了总体电导率。复杂阻抗谱表明，随着Gd浓度的增加，掺杂样品的实际阻抗值更高。这些发现阐明了Gd对磁铁矿纳米颗粒电性能的影响，并强调了它们在满足能源存储和电子设备中对高效技术日益增长的需求方面的重要性。图形抽象

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引用次数: 0

A comparative analysis of optical and electrical properties of pure CuO and Zn doped CuO nanoparticles for optoelectronic device applications 光电器件用纯CuO和掺杂Zn的CuO纳米颗粒的光学和电学性质的比较分析

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-10-28 DOI: 10.1007/s10971-024-06591-7

Shahroz Saleem, Awais Khalid, Zaid M. Aldhafeeri, Thamer Alomayri, Arshad Ali, Abdul Jabbar, M. Yasmin Begum, Geetha Kandasamy

A sol-gel auto-combustion was used to prepare both pure and Zn-doped CuO NPs. The effect of Zn²⁺ on the electrical properties was investigated for use in optoelectronic device applications. The XRD analysis exhibited the synthesized CuO has a single monoclinic phase with a ZnO secondary phase. SEM micrographs show the spherical and cubic structure of the pure and Zn-doped CuO NPs, respectively. The average crystalline size, lattice constants, dislocation density, and microstrain were measured in the range of 25.23–21.18 nm, 7.893–7.745 A°, 1.57–2.22 × 10¹⁵m⁻² and −3.55 × 10⁻⁴× to –4.34 × 10⁻⁴, respectively. The Raman results revealed that sharper and stronger peaks were detected which also shifted to higher wavenumbers with declining particle size which are well matched to XRD results and revealed the pureness of the samples. The band gap was estimated with Tauc’s equation, and the findings showed that the addition of Zn²⁺ ions increased the band gap’s energy from 1.47 eV to 1.62 eV. To ascertain the electrical characteristics of produced nanoparticles, electrical characteristic investigations were carried out. From the consequences, it has been analyzed that electrical resistivity enhanced from 9.12 × 10³ to 4.84 × 10⁴ Ω cm with the addition of Zn in CuO. Based on the obtained consequences, it can be predicted that the modified electrical and optical properties of the prepared CuO nanoparticles can make them a potential candidate for optoelectronic applications, if control the generation of secondary phase, band gap enhancement, and generation of oxygen vacancies, because these factor influences the charge carrier’s mobility.

Graphical Abstract

采用溶胶-凝胶自燃烧法制备了纯CuO纳米粒子和掺锌CuO纳米粒子。研究了Zn2+对光电器件电学性能的影响。XRD分析表明，合成的CuO为单斜相，ZnO为次级相。SEM显微图显示了纯CuO纳米粒子和掺锌CuO纳米粒子的球形和立方结构。在25.23 ~ 21.18 nm、7.893 ~ 7.745 A°、1.57 ~ 2.22 × 1015 m−2和- 3.55 × 10−4 ~ -4.34 × 10−4范围内测量了晶体的平均晶粒尺寸、晶格常数、位错密度和微应变。拉曼光谱结果表明，随着粒径的减小，样品的谱峰更尖锐、更强，且谱峰向更高的波数偏移，这与XRD结果吻合较好，从而揭示了样品的纯度。利用Tauc方程对带隙进行了估算，结果表明，Zn2+离子的加入使带隙的能量从1.47 eV增加到1.62 eV。为了确定制备的纳米颗粒的电特性，进行了电特性研究。结果表明，在CuO中加入Zn后，其电阻率由9.12 × 103提高到4.84 × 104 Ω cm。基于所获得的结果，可以预测制备的CuO纳米颗粒的电学和光学性质可以使其成为光电应用的潜在候选者，如果控制二次相的产生，带隙增强和氧空位的产生，因为这些因素会影响载流子的迁移率。图形抽象

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引用次数: 0

Revolutionizing energy storage and electro-catalysis: unleashing electrode power with novel BaS3:La2S3:Ho2S3 synthesized from single-source precursors for enhanced electrochemical functionality 革命性的能量储存和电催化：释放电极功率与新型BaS3:La2S3:Ho2S3合成从单一来源前体增强电化学功能

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-10-26 DOI: 10.1007/s10971-024-06599-z

Shaan Bibi Jaffri, Khuram Shahzad Ahmad, Jehad S. Al-Hawadi, Bhumikaben Makawana, Ram K. Gupta, Ghulam Abbas Ashraf, Mohammad K. Okla

Electrochemical energy storage has utility in wide range of systems, therefore scientific community and energy stakeholders have been significantly focusing especially on it. By utilizing the novel BaS₃:La₂S₃:Ho₂S₃ semiconductor, an alkaline earth-lanthanide composite chalcogenide (AE-LCC), which is developed by chelating with the diethyldithiocarbamate ligand, the current work, for the first time, seeks to enhance the performance of charge retaining devices in addition to electro-catalysis. This photo-active material exhibits exceptional optical properties with a band gap of 3.95 eV and heterogeneous crystallographic modes with a median crystallite size of 17.78 nm, due to its sustainable manufacturing process. Furthermore, infrared spectroscopy was used to identify metallic sulfide connections, which vary between 545 and 887 cm⁻¹. Differently shaped particles that fused into a rod-like structure showed a higher volume-surface area ratio at multiple locations. The electrochemical performance of the BaS₃:La₂S₃:Ho₂S₃ AE-LCC was assessed using a conventional three-electrode configuration with an initial electrolyte of 1 M KOH. BaS₃:La₂S₃:Ho₂S₃ AE-LCC exhibits excellent specific capacitance of as high as 779 F g⁻¹ and a power density of 10,145.28 W kg⁻¹, making it an excellent electrode material for power storage applications. This remarkable electrochemical performance was further substantiated by comparable series resistance (R_s) = 1.25 Ω. The electrode generated an OER overpotential and a matching Tafel slope of 417 mV and 113 mV/dec by electro-catalysis. Conversely, the Tafel slope of HER activity was 310 mV/dec, and its overpotential was 233 mV.

Graphical Abstract

电化学储能在广泛的系统中具有广泛的应用价值，因此受到了科学界和能源利益相关者的极大关注。利用新型的BaS3:La2S3:Ho2S3半导体，一种碱土-镧系化合物硫系化合物（AE-LCC），通过与二乙基二硫代氨基甲酸酯配体螯合而成，本研究首次寻求在电催化之外提高电荷保持器件的性能。由于其可持续的制造工艺，该光活性材料具有优异的光学性能，其带隙为3.95 eV，中位晶尺寸为17.78 nm，具有异质晶体模式。此外，红外光谱用于识别金属硫化物连接，其变化范围在545至887 cm−1之间。不同形状的颗粒融合成棒状结构，在多个位置显示出更高的体积比。采用传统的三电极结构，初始电解液为1 M KOH，对BaS3:La2S3:Ho2S3 AE-LCC的电化学性能进行了评价。BaS3:La2S3:Ho2S3 AE-LCC具有优异的比电容，高达779 F g−1，功率密度为10,145.28 W kg−1，是一种极好的储能电极材料。串联电阻(Rs) = 1.25 Ω进一步证实了这一卓越的电化学性能。电极通过电催化作用产生OER过电位和匹配的Tafel斜率分别为417 mV和113 mV/dec。相反，HER活性的Tafel斜率为310 mV/dec，过电位为233 mV。图形抽象

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引用次数: 0

Preparation of monolithic silica HPLC columns with truss-structured skeletons and embedded surfactant-templated mesopores 具有桁架骨架和嵌入表面活性剂模板介孔的整体硅胶高效液相色谱柱的制备

IF 2.3 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS

Journal of Sol-Gel Science and Technology

Pub Date : 2024-10-26 DOI: 10.1007/s10971-024-06595-3

Takanori Detani, Kei Morisato, Masayoshi Ohira, Kazuki Nakanishi

Monolithic macro/mesoporous silica gels have been prepared via a sol-gel process using triblock copolymer Pluronic P123 (EO₂₀PO₇₀EO₂₀) as a structure-directing agent. In this synthesis, P123 not only induces phase separation to form macroporous structure but also acts as a supramolecular template to form mesopores with precisely controlled shape and size. Obtained was a monolithic silica composed of continuous truss-like columnar skeletons in which cylindrical mesopores are arranged in a 2D-hexagonal symmetry. These monolithic silica gels have extremely high porosity approaching 90% and exhibited high specific surface area and sharp pore size distribution as revealed by N₂ sorption measurements. Combinations of the initial composition and the post-gelation treatment on wet gels allowed the control of physical properties of meso- and macropore structures. The monolithic HPLC columns prepared using these silica gels surface-modified by ODS (octadecylsilyl) ligands gave as many as 140,000 theoretical plates/m for the separation of alkylbenzenes in a reversed-phase mode. Very weak dependence of height equivalent to theoretical plate, H, on the mobile phase velocity was also recognized in comparison with conventional particle-packed columns.

Graphical Abstract

SEM images of monolithic silica prepared with tetramethoxysilane (TMOS) and P123 composed of truss-structured continuous skeletons. The performance for HPLC separation medium was examined.

以三嵌段共聚物Pluronic P123 （EO20PO70EO20）为结构导向剂，采用溶胶-凝胶法制备了整体宏/介孔硅胶。在该合成中，P123不仅诱导相分离形成大孔结构，而且作为超分子模板形成具有精确控制形状和大小的介孔。获得的是由连续的桁架状柱状骨架组成的整体二氧化硅，其中圆柱形介孔以二维六边形对称排列。N2吸附测试结果表明，硅胶整体孔隙率高达90%，比表面积高，孔径分布明显。湿凝胶的初始组成和凝胶化后处理的组合可以控制介孔和大孔结构的物理性质。用ODS（十八烷基硅基）配体表面修饰的硅胶制备的整体高效液相色谱柱在反相模式下分离烷基苯的理论极板数高达14万/m。与传统的颗粒填充柱相比，还认识到与理论板等效高度H对流动相速度的依赖性非常弱。四甲基氧基硅烷（TMOS）和P123组成的桁架结构连续骨架制备的单片二氧化硅的sem图像。考察了其作为高效液相色谱分离介质的性能。

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