Pub Date : 2024-09-08DOI: 10.1007/s10971-024-06535-1
Rei Nakayama, Yuki Yamaguchi, Hirofumi Sumi
To achieve carbon neutrality by 2050, novel ceramic processes which can fabricate it at lower temperatures compared with conventional sintering process are required. Bulk barium titanate (BaTiO3) is directly synthesized from hydrous titania gel (TiO2·nH2O) pellets near room temperature via the acid–base chemical densification (ABCD) process, which affords perovskite oxides via neutralization reactions. TiO2·nH2O used as precursor material has amorphous structure and includes a trace amount of water in its structure. Scanning electron microscopy images show that the mechanism of BaTiO3 crystallization in TiO2·nH2O pellet is dependent on the reaction conditions in the barium hydroxide solution, including the heat-treating temperature and time. The bulk BaTiO3 are obtained from TiO2·nH2O pellets by treating below 100 °C for a long time more than 25 h; however, heat-treating at higher temperatures caused TiO2·nH2O pellets to disintegrate. It is consolidated that dominant reaction, whether the diffusion reaction or a dissolution–precipitation reaction, in this process depends on the reaction temperature and time. Then, at higher temperatures than 120 °C, a part of TiO2·nH2O pellets dissolve to barium hydroxide solution as a dissolution–precipitation reaction. In contrast, at below 120 °C, BaTiO3 bulk is obtained by diffusion reaction of Ba ion into TiO2·nH2O pellet.
{"title":"Crystallization mechanism of barium titanate in amorphous titania gel pellets by acid–base chemical densification near room temperature","authors":"Rei Nakayama, Yuki Yamaguchi, Hirofumi Sumi","doi":"10.1007/s10971-024-06535-1","DOIUrl":"https://doi.org/10.1007/s10971-024-06535-1","url":null,"abstract":"<p>To achieve carbon neutrality by 2050, novel ceramic processes which can fabricate it at lower temperatures compared with conventional sintering process are required. Bulk barium titanate (BaTiO<sub>3</sub>) is directly synthesized from hydrous titania gel (TiO<sub>2</sub>·nH<sub>2</sub>O) pellets near room temperature via the acid–base chemical densification (ABCD) process, which affords perovskite oxides via neutralization reactions. TiO<sub>2</sub>·nH<sub>2</sub>O used as precursor material has amorphous structure and includes a trace amount of water in its structure. Scanning electron microscopy images show that the mechanism of BaTiO<sub>3</sub> crystallization in TiO<sub>2</sub>·nH<sub>2</sub>O pellet is dependent on the reaction conditions in the barium hydroxide solution, including the heat-treating temperature and time. The bulk BaTiO<sub>3</sub> are obtained from TiO<sub>2</sub>·nH<sub>2</sub>O pellets by treating below 100 °C for a long time more than 25 h; however, heat-treating at higher temperatures caused TiO<sub>2</sub>·nH<sub>2</sub>O pellets to disintegrate. It is consolidated that dominant reaction, whether the diffusion reaction or a dissolution–precipitation reaction, in this process depends on the reaction temperature and time. Then, at higher temperatures than 120 °C, a part of TiO<sub>2</sub>·nH<sub>2</sub>O pellets dissolve to barium hydroxide solution as a dissolution–precipitation reaction. In contrast, at below 120 °C, BaTiO<sub>3</sub> bulk is obtained by diffusion reaction of Ba ion into TiO<sub>2</sub>·nH<sub>2</sub>O pellet.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142196022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-08DOI: 10.1007/s10971-024-06536-0
Yongmin Shin, Somin Park, Byung Jo Um, Seungwan Kim, Junho Jang, Byeong-Soo Bae
Luminescent nanocrystals (NCs) have emerged as the high-performance wavelength converting materials in next-generation displays and energy conversion devices due to their unique optophysical properties, such as large Stokes or anti-Stokes shifts, narrow emission bandwidth, and tunable bandgap depending on size or composition. However, poor long-term stability in high temperature and humidity remains a critical issue for device applications. This instability is primarily due to irreversible changes in surface ligands or chemical structures/compositions when exposed to various severe environments. Various strategies have been reported to address these issues, such as the formation of inorganic shell layers and the fabrication of polymer-based nanocomposites. Although these strategies have improved stability, they exhibit degraded properties during long-term aging. Recently, sol–gel derived siloxane hybrid materials have been introduced to achieve stability for various NCs under actual operating conditions of displays and optoelectronic devices. This review will address recent progress in developing siloxane-encapsulated NCs with high stability in high temperature/humidity and under continuous light exposure. It will also introduce results on enhancing the environmental stability of various NCs, including lanthanide-doped transition metal-based NCs, semiconducting NCs, and metal halide perovskite NCs, as well as demonstrations of reliable devices.
{"title":"Highly stable wavelength converting composite based on sol–gel derived siloxane-encapsulated luminescent nanocrystals","authors":"Yongmin Shin, Somin Park, Byung Jo Um, Seungwan Kim, Junho Jang, Byeong-Soo Bae","doi":"10.1007/s10971-024-06536-0","DOIUrl":"https://doi.org/10.1007/s10971-024-06536-0","url":null,"abstract":"<p>Luminescent nanocrystals (NCs) have emerged as the high-performance wavelength converting materials in next-generation displays and energy conversion devices due to their unique optophysical properties, such as large Stokes or anti-Stokes shifts, narrow emission bandwidth, and tunable bandgap depending on size or composition. However, poor long-term stability in high temperature and humidity remains a critical issue for device applications. This instability is primarily due to irreversible changes in surface ligands or chemical structures/compositions when exposed to various severe environments. Various strategies have been reported to address these issues, such as the formation of inorganic shell layers and the fabrication of polymer-based nanocomposites. Although these strategies have improved stability, they exhibit degraded properties during long-term aging. Recently, sol–gel derived siloxane hybrid materials have been introduced to achieve stability for various NCs under actual operating conditions of displays and optoelectronic devices. This review will address recent progress in developing siloxane-encapsulated NCs with high stability in high temperature/humidity and under continuous light exposure. It will also introduce results on enhancing the environmental stability of various NCs, including lanthanide-doped transition metal-based NCs, semiconducting NCs, and metal halide perovskite NCs, as well as demonstrations of reliable devices.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142196020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To prevent the worldwide diseases caused by the micro-organisms, the great effort has been performed to synthesize unique CuO nanoflakes (NF) and walnut shape (W-S) CuO/CeO2 heterostructures with O vacancies by a simple precipitation technique without using any template. The morphology, structure, valance states, chemical composition and surface charge of the synthesized samples were inspected by i.e. scanning electron microscope (SEM), energy dispersive X-Ray (EDX), resolution transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential (ζ). The expected crystallite’s size was studied by XRD data i.e. for CuO NF ~5.9 nm with 0.1–0.2% error and SD is ±0.2–0.5, while for the W-S CuO/CeO2 heterostructures it is about ~6.4 nm with 0.05–0.1% error and SD is ±0.1–0.2 respectively. Both samples were tested as an antiseptic agent against E. coli and S. aureus, and it was confirmed that they had greater antibacterial effects as compared to the control group (water) which showed no response (0%). It was predicted that the CuO/CeO2 heterostructure showed excellent antibacterial activity (100%) verses pure CuO NF (80–90%) at the same 0.2 mg/L concentration for E. coli with SD (±0–1). While against S. Aureus strain the CuO/CeO2 heterostructure showed (80–90%) antibacterial action at the lowest concentration (0.2 mg/L) but 100% as the concentration increases i.e. 0.5 mg/L due to difference in bacterial strain with the SD (±0–2). After remarkable antibacterial activity, the biofilm inhibition of CuO/CeO2 heterostructure against S. aureus was also studied by crystal violet staining, and examined that the inhibition effect of the biofilm increases with the increase concentration of heterostructures. At 0.31 mg/mL, the biofilm reduced visibly and the whole structure has destroyed, indicating that it is a remarkable biofilm inhibitor.
{"title":"Template free synthesis of CuO nanoflakes and walnut shape CuO/CeO2 heterostructures: characterization and their role as an antibacterial materials and biofilm inhibitors","authors":"Kanwal Javed, Yufang Ren, Sobia Kousar, Yifan Liu, Zhenhao Cao, Bushra Begum, Xue Li","doi":"10.1007/s10971-024-06533-3","DOIUrl":"https://doi.org/10.1007/s10971-024-06533-3","url":null,"abstract":"<p>To prevent the worldwide diseases caused by the micro-organisms, the great effort has been performed to synthesize unique CuO nanoflakes (NF) and walnut shape (W-S) CuO/CeO<sub>2</sub> heterostructures with O vacancies by a simple precipitation technique without using any template. The morphology, structure, valance states, chemical composition and surface charge of the synthesized samples were inspected by i.e. scanning electron microscope (SEM), energy dispersive X-Ray (EDX), resolution transmission electron microscope (TEM), high resolution transmission electron microscope (HRTEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and zeta potential (ζ). The expected crystallite’s size was studied by XRD data i.e. for CuO NF ~5.9 nm with 0.1–0.2% error and SD is ±0.2–0.5, while for the W-S CuO/CeO<sub>2</sub> heterostructures it is about ~6.4 nm with 0.05–0.1% error and SD is ±0.1–0.2 respectively. Both samples were tested as an antiseptic agent against <i>E. coli</i> and <i>S. aureus</i>, and it was confirmed that they had greater antibacterial effects as compared to the control group (water) which showed no response (0%). It was predicted that the CuO/CeO<sub>2</sub> heterostructure showed excellent antibacterial activity (100%) verses pure CuO NF (80–90%) at the same 0.2 mg/L concentration for <i>E. coli</i> with SD (±0–1). While against <i>S. Aureus</i> strain the CuO/CeO<sub>2</sub> heterostructure showed (80–90%) antibacterial action at the lowest concentration (0.2 mg/L) but 100% as the concentration increases i.e. 0.5 mg/L due to difference in bacterial strain with the SD (±0–2). After remarkable antibacterial activity, the biofilm inhibition of CuO/CeO<sub>2</sub> heterostructure against <i>S. aureus</i> was also studied by crystal violet staining, and examined that the inhibition effect of the biofilm increases with the increase concentration of heterostructures. At 0.31 mg/mL, the biofilm reduced visibly and the whole structure has destroyed, indicating that it is a remarkable biofilm inhibitor.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Developing sustainable synthesis method of versatile zeolites to overcome the shortcoming of traditional process is of significant for development of green chemistry and environmentally friendly techniques. In this work, MFI zeolite (ZSM-5) was synthesized through organotemplate-, solvent- and seed-free sustainable process comprising physical grinding and quasi-solid state crystallization and utilizing commercial silica gel or Stöber colloidal SiO2 as silica source. The key influencing factors to this sustainable synthesis process, such as starting material composition, crystallization temperature and time, had been unambiguously investigated by combining a series of characterization techniques. It is revealed that the starting material with SiO2/Al2O3 and Na2O/SiO2 at 30–40 and 0.072, respectively, is suitable to obtain zeolite product with high crystallinity. The presence of right amount of water (or alcohol) is also crucial. In addition, this green synthesis method can be extended into the fabrication of encapsulated metal-zeolite bifunctional catalyst, which is effective in hydroisomerization of n-heptane. These results are instructive for development of sustainable synthesis of aluminosilicate zeolites and derived heterogeneous catalysts.
{"title":"Sustainable synthesis of MFI zeolite and derived metal-acid bifunctional catalysts for hydroisomerization of n-heptane","authors":"Mengxuan Zhu, Wenqi Xu, Longyang Wang, Rui Wang, Heng Jiang, Changzi Jin","doi":"10.1007/s10971-024-06542-2","DOIUrl":"https://doi.org/10.1007/s10971-024-06542-2","url":null,"abstract":"<p>Developing sustainable synthesis method of versatile zeolites to overcome the shortcoming of traditional process is of significant for development of green chemistry and environmentally friendly techniques. In this work, MFI zeolite (ZSM-5) was synthesized through organotemplate-, solvent- and seed-free sustainable process comprising physical grinding and quasi-solid state crystallization and utilizing commercial silica gel or Stöber colloidal SiO<sub>2</sub> as silica source. The key influencing factors to this sustainable synthesis process, such as starting material composition, crystallization temperature and time, had been unambiguously investigated by combining a series of characterization techniques. It is revealed that the starting material with SiO<sub>2</sub>/Al<sub>2</sub>O<sub>3</sub> and Na<sub>2</sub>O/SiO<sub>2</sub> at 30–40 and 0.072, respectively, is suitable to obtain zeolite product with high crystallinity. The presence of right amount of water (or alcohol) is also crucial. In addition, this green synthesis method can be extended into the fabrication of encapsulated metal-zeolite bifunctional catalyst, which is effective in hydroisomerization of <i>n</i>-heptane. These results are instructive for development of sustainable synthesis of aluminosilicate zeolites and derived heterogeneous catalysts.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The judicious use of transition metals, notably vanadium (V), is critical to improving zinc oxide (ZnO) photoelectric performance. This research reveals the transforming effect of different V doping levels on zinc oxide (V:ZnO) thin films precisely manufactured using a sol-gel dip-coating process. X-ray diffraction (XRD) reveals the evolving characteristics of the films, revealing a shift towards increased structural coherence and preferred orientation as V doping concentrations increase. Scanning electron microscopy (SEM) and its nano texture fractal studies reveal a gradual refinement in the texture and arrangement of V:ZnO films with increased doping levels. The effective V doping inside the ZnO thin films is confirmed by energy dispersive spectroscopy (EDS). Furthermore, the ultraviolet-visible (UV-Vis) absorption coefficient increases when the Urbach energy (EU) increases and the energy gap (Eg) decreases. Notably, V:ZnO displays exceptional emissions in the intrinsic excitation region at 300 nmand within the defect emission range of 380–650 nm at 3% dopingmaking it a promising candidate for blue LED applications. However, care is advised since extensive doping may impair the photoluminescence properties of ZnO. Urbach tails in weak absorption region decreased with increasing % of V in ZnO. Urbach energies (Eu) were in the 0.32–0.52 meV range for as-deposited and annealed films. This was used to account for the disorder of the films—an inverse relation was observed between Urbach energy and optical band energy as a result of doping. Research findings presented in this work give significant information on the complexities of V doping in ZnO, paving the way for advanced optoelectronic applications, particularly in blue LEDs.
Graphical Abstract
合理使用过渡金属，特别是钒（V），对于提高氧化锌（ZnO）的光电性能至关重要。这项研究揭示了不同钒掺杂水平对采用溶胶-凝胶浸涂工艺精确制造的氧化锌（V:ZnO）薄膜的转化效应。X 射线衍射 (XRD) 揭示了薄膜不断变化的特性，显示出随着 V 掺杂浓度的增加，薄膜的结构一致性和优先取向性也在增加。扫描电子显微镜（SEM）及其纳米纹理分形研究显示，随着掺杂水平的提高，氧化锌薄膜的纹理和排列逐渐细化。能量色散光谱（EDS）证实了氧化锌薄膜中有效的钒掺杂。此外，当乌尔巴赫能（EU）增加、能隙（Eg）减小时，紫外可见（UV-Vis）吸收系数也会增加。值得注意的是，在掺杂 3% 时，V:ZnO 在 300 纳米的本征激发区域和 380-650 纳米的缺陷发射范围内显示出卓越的发射性能，使其成为蓝光 LED 应用的理想候选材料。然而，由于大量掺杂可能会损害氧化锌的光致发光特性，因此应谨慎使用。随着氧化锌中 V 含量的增加，弱吸收区的 Urbach 尾随也随之减少。淀积和退火薄膜的厄巴赫能量（Eu）在 0.32-0.52 meV 范围内。这可以用来解释薄膜的无序性--由于掺杂，观察到厄巴赫能和光带能之间存在反比关系。这项研究成果提供了有关氧化锌中掺杂 V 的复杂性的重要信息，为先进的光电应用，尤其是蓝光 LED 的应用铺平了道路。
{"title":"Structural, nano texture, and optical study of Vanadium-doped zinc oxide thin films for blue LEDs","authors":"Apoorva Katoch, Navneet Kaur, Davinder Kumar, Balraj Singh, Vandana Shinde, Raminder Kaur","doi":"10.1007/s10971-024-06517-3","DOIUrl":"https://doi.org/10.1007/s10971-024-06517-3","url":null,"abstract":"<p>The judicious use of transition metals, notably vanadium (V), is critical to improving zinc oxide (ZnO) photoelectric performance. This research reveals the transforming effect of different V doping levels on zinc oxide (V:ZnO) thin films precisely manufactured using a sol-gel dip-coating process. X-ray diffraction (XRD) reveals the evolving characteristics of the films, revealing a shift towards increased structural coherence and preferred orientation as V doping concentrations increase. Scanning electron microscopy (SEM) and its nano texture fractal studies reveal a gradual refinement in the texture and arrangement of V:ZnO films with increased doping levels. The effective V doping inside the ZnO thin films is confirmed by energy dispersive spectroscopy (EDS). Furthermore, the ultraviolet-visible (UV-Vis) absorption coefficient increases when the Urbach energy (E<sub>U</sub>) increases and the energy gap (E<sub>g</sub>) decreases. Notably, V:ZnO displays exceptional emissions in the intrinsic excitation region at 300 <i>nm</i>and within the defect emission range of 380–650 <i>nm</i> at 3% dopingmaking it a promising candidate for blue LED applications. However, care is advised since extensive doping may impair the photoluminescence properties of ZnO. Urbach tails in weak absorption region decreased with increasing % of V in ZnO. Urbach energies (E<sub>u</sub>) were in the 0.32–0.52 meV range for as-deposited and annealed films. This was used to account for the disorder of the films—an inverse relation was observed between Urbach energy and optical band energy as a result of doping. Research findings presented in this work give significant information on the complexities of V doping in ZnO, paving the way for advanced optoelectronic applications, particularly in blue LEDs.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-02DOI: 10.1007/s10971-024-06495-6
Mukhtiar Hussain, Abdelaziz Gassoumi, Ilya A. Weinstein, A. Kahshan, Khursheed Ahmad, A. M. A. Henaish
Developing cutting-edge catalysts for oxygen evolution reaction (OER) is crucial for enhancing the efficiency of water splitting. Spinel-type materials have gained recognition for their exceptional catalytic performance in OER activity. The excessive OER overpotential is the significant obstacle that hinders the use of spinel-type materials. In this work, polyaniline (PANI) was incorporated to significantly enhance the performance of spinel SnFe2O4 material by straightforward hydrothermal method. SnFe2O4@PANI catalyst demonstrated an impressive overpotential of 198 mV at 10 mA cm–2 and a 33 mV dec–1 Tafel slope with higher OER activity. The electrochemical surface area (ECSA) of SnFe2O4@PANI catalyst was determined to be 2348.53 cm2, with higher cyclic stability of 25 h after 5000th cycles with minimal impedance characteristics (Rct = 0.18 Ω). In addition, the findings showed that the inclusion of PANI led to expansion of the surface area to improve the conductivity, resulting in notable enhancement of the catalysts’ OER activity. This modification has resulted in an improved OER catalyst, making it highly sought after for various applications in the water-splitting field.
Graphical Abstract
开发用于氧进化反应（OER）的尖端催化剂对于提高水分离效率至关重要。尖晶石型材料因其在氧进化反应活性方面的优异催化性能而获得认可。过高的 OER 过电位是阻碍尖晶石型材料应用的主要障碍。在这项工作中，通过直接水热法加入聚苯胺（PANI），显著提高了尖晶石 SnFe2O4 材料的性能。SnFe2O4@PANI 催化剂在 10 mA cm-2 时的过电位为 198 mV，Tafel 斜率为 33 mV dec-1，具有更高的 OER 活性。经测定，SnFe2O4@PANI 催化剂的电化学表面积（ECSA）为 2348.53 平方厘米，具有更高的循环稳定性，在循环 5000 次后仍能保持 25 小时，阻抗特性极小（Rct = 0.18 Ω）。此外，研究结果表明，PANI 的加入扩大了表面积，从而提高了导电性，显著增强了催化剂的 OER 活性。这种改性催化剂改善了 OER 的性能，使其在水分离领域的各种应用中备受青睐。
{"title":"Fabrication of high performance SnFe2O4@PANI electrocatalyst for Oxygen Evaluation Reaction (OER) by hydrothermal method","authors":"Mukhtiar Hussain, Abdelaziz Gassoumi, Ilya A. Weinstein, A. Kahshan, Khursheed Ahmad, A. M. A. Henaish","doi":"10.1007/s10971-024-06495-6","DOIUrl":"https://doi.org/10.1007/s10971-024-06495-6","url":null,"abstract":"<p>Developing cutting-edge catalysts for oxygen evolution reaction (OER) is crucial for enhancing the efficiency of water splitting. Spinel-type materials have gained recognition for their exceptional catalytic performance in OER activity. The excessive OER overpotential is the significant obstacle that hinders the use of spinel-type materials. In this work, polyaniline (PANI) was incorporated to significantly enhance the performance of spinel SnFe<sub>2</sub>O<sub>4</sub> material by straightforward hydrothermal method. SnFe<sub>2</sub>O<sub>4</sub>@PANI catalyst demonstrated an impressive overpotential of 198 mV at 10 mA cm<sup>–2</sup> and a 33 mV dec<sup>–1</sup> Tafel slope with higher OER activity. The electrochemical surface area (ECSA) of SnFe<sub>2</sub>O<sub>4</sub>@PANI catalyst was determined to be 2348.53 cm<sup>2</sup>, with higher cyclic stability of 25 h after 5000th cycles with minimal impedance characteristics (R<sub>ct</sub> = 0.18 Ω). In addition, the findings showed that the inclusion of PANI led to expansion of the surface area to improve the conductivity, resulting in notable enhancement of the catalysts’ OER activity. This modification has resulted in an improved OER catalyst, making it highly sought after for various applications in the water-splitting field.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-31DOI: 10.1007/s10971-024-06523-5
Hiromitsu Kozuka, Yuta Miyao, Tomoaki Kato, Manato Miki
Maintaining the water wettability for extended period is generally tough to achieve on solid surface. We stored a soda-lime glass plate in a container equipped with an air purifier with a fan filter, where the water contact angle increased from 3° to 33° in 2 days. X-ray photoelectron spectroscopic (XPS) spectra obtained on the glass surface showed that hydrocarbons increased in amount during storage, indicating their adsorption as one of the causes of the increased contact angle during storing. Next we prepared lithium silicate thin films with nominal Li/Si mole ratios of 0.12–0.86 on Si(100) wafers by sol-gel method from lithium nitrate-tetraethyl orthosilicate solutions. The films were stored in the container with the air purifier, and the water contact angle was measured as a function of storage time. The films of Li/Si ≥ 0.24 kept contact angles lower than 15° over 10 days although hydrocarbons increased in amount on the surface during storage, which was examined by XPS analysis on the film of Li/Si = 0.24. The film surface turned cloudy during storage, which we attributed to lithium carbonate precipitates by field emission scanning electron microscopy (FE-SEM) and infrared (IR) absorption spectroscopy. We thought that hydrocarbons adsorbed on lithium carbonate precipitates may be washed out when a water droplet is placed on the film surface in contact angle measurements, and that such hydrocarbon removal may lead to the long-term duration of the low contact angle. Elemental depth profile analysis by XPS showed that Li+ ions leach out from the film during soaking in water, resulting in the formation of a silica film. We expected the resulting silica film to be porous and hence to exhibit persistent low water contact angle due to capillary effect. However, the film showed higher initial contact angles, which further increased during storing. The silica film was unexpectedly relatively dense, which was revealed by refractive index measurements, not having porous nature with persistent hydrophilicity.
{"title":"Changes in the wettability of the surface of soda-lime glass and of sol-gel-derived lithium silicate thin films during storage at room temperature","authors":"Hiromitsu Kozuka, Yuta Miyao, Tomoaki Kato, Manato Miki","doi":"10.1007/s10971-024-06523-5","DOIUrl":"https://doi.org/10.1007/s10971-024-06523-5","url":null,"abstract":"<p>Maintaining the water wettability for extended period is generally tough to achieve on solid surface. We stored a soda-lime glass plate in a container equipped with an air purifier with a fan filter, where the water contact angle increased from 3° to 33° in 2 days. X-ray photoelectron spectroscopic (XPS) spectra obtained on the glass surface showed that hydrocarbons increased in amount during storage, indicating their adsorption as one of the causes of the increased contact angle during storing. Next we prepared lithium silicate thin films with nominal Li/Si mole ratios of 0.12–0.86 on Si(100) wafers by sol-gel method from lithium nitrate-tetraethyl orthosilicate solutions. The films were stored in the container with the air purifier, and the water contact angle was measured as a function of storage time. The films of Li/Si ≥ 0.24 kept contact angles lower than 15° over 10 days although hydrocarbons increased in amount on the surface during storage, which was examined by XPS analysis on the film of Li/Si = 0.24. The film surface turned cloudy during storage, which we attributed to lithium carbonate precipitates by field emission scanning electron microscopy (FE-SEM) and infrared (IR) absorption spectroscopy. We thought that hydrocarbons adsorbed on lithium carbonate precipitates may be washed out when a water droplet is placed on the film surface in contact angle measurements, and that such hydrocarbon removal may lead to the long-term duration of the low contact angle. Elemental depth profile analysis by XPS showed that Li<sup>+</sup> ions leach out from the film during soaking in water, resulting in the formation of a silica film. We expected the resulting silica film to be porous and hence to exhibit persistent low water contact angle due to capillary effect. However, the film showed higher initial contact angles, which further increased during storing. The silica film was unexpectedly relatively dense, which was revealed by refractive index measurements, not having porous nature with persistent hydrophilicity.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-30DOI: 10.1007/s10971-024-06480-z
M. Sarmast Sh, A. B. Dayang Radiah, D. A. Hoey, N. Abdullah, H. S. Zainuddin, S. Kamarudin
The challenges of forming a crystalline phase within 45S5 Bioglass® (45% SiO2-24.5% CaO-24.5% Na2O-6% P2O5 mol%) and its subsequent influence on the bioactivity of the bioglass were studied in this research. Bioglasses were sintered at 1400, 750, and 550 °C, using both melting and sol-gel methods. The different responses of bioglasses to different sintering temperatures were revealed. Particularly, increased crystallinity was observed in sol-gel-derived bioglass sintered at 750 °C, indicating a denser and more ordered structure. This crystalline architecture facilitated enhanced bioactivity, as demonstrated by increased hydroxyapatite deposition when immersed in simulated body fluid (SBF). Furthermore, superior mechanical properties and biocompatibility were achieved with this temperature regime, making it a prime candidate for bone regeneration applications. The bioglass sintered at 750 °C exhibited an accelerated degradation rate associated with its porosity, potentially contributing to faster material resorption in vivo. Its antibacterial efficacy against E. coli and S. aureus was also noted, and in vitro studies with MTT assay confirmed that the optimized sol-gel bioglass meets biocompatibility standards. These findings highlight the potential of fine-tuning the sintering temperature to modulate the crystallinity of bioglasses, thereby enhancing their application scope in bone tissue engineering.
{"title":"The structural, mechanical, and biological variation of silica bioglasses obtained by different sintering temperatures","authors":"M. Sarmast Sh, A. B. Dayang Radiah, D. A. Hoey, N. Abdullah, H. S. Zainuddin, S. Kamarudin","doi":"10.1007/s10971-024-06480-z","DOIUrl":"https://doi.org/10.1007/s10971-024-06480-z","url":null,"abstract":"<p>The challenges of forming a crystalline phase within 45S5 Bioglass<sup>®</sup> (45% SiO<sub>2</sub>-24.5% CaO-24.5% Na<sub>2</sub>O-6% P<sub>2</sub>O<sub>5</sub> mol%) and its subsequent influence on the bioactivity of the bioglass were studied in this research. Bioglasses were sintered at 1400, 750, and 550 °C, using both melting and sol-gel methods. The different responses of bioglasses to different sintering temperatures were revealed. Particularly, increased crystallinity was observed in sol-gel-derived bioglass sintered at 750 °C, indicating a denser and more ordered structure. This crystalline architecture facilitated enhanced bioactivity, as demonstrated by increased hydroxyapatite deposition when immersed in simulated body fluid (SBF). Furthermore, superior mechanical properties and biocompatibility were achieved with this temperature regime, making it a prime candidate for bone regeneration applications. The bioglass sintered at 750 °C exhibited an accelerated degradation rate associated with its porosity, potentially contributing to faster material resorption in vivo. Its antibacterial efficacy against <i>E. coli</i> and <i>S. aureus</i> was also noted, and in vitro studies with MTT assay confirmed that the optimized sol-gel bioglass meets biocompatibility standards. These findings highlight the potential of fine-tuning the sintering temperature to modulate the crystallinity of bioglasses, thereby enhancing their application scope in bone tissue engineering.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-30DOI: 10.1007/s10971-024-06512-8
Giuseppe Angellotti, Cristina Riccucci, Gabriella Di Carlo, Mario Pagliaro, Rosaria Ciriminna
Showing broad scope pesticidal properties, the Origanum vulgare essential oil is highly volatile, limiting effective agricultural applications. Aiming to develop new environmentally friendly and effective biopesticide based on O. vulgare essential oil we carried out its template-assisted sol-gel microencapsulation within silica microcapsules. The method affords mesoporous SiO2 spherical particles about 430 nm in size with uniform size distribution (polydispersion index of 0.184) having encapsulation efficiency up to 13.7 wt%, and large positive zeta potential of 22.8 mV. Dubbed herein “SiliOregan”, this new class of sol-gel materials is promising towards the development of solid biopesticides formulated in water for pest management against fungi, insects, bacteria, nematodes, and mites.
{"title":"Towards sustainable pest management of broad scope: sol-gel microencapsulation of Origanum vulgare essential oil","authors":"Giuseppe Angellotti, Cristina Riccucci, Gabriella Di Carlo, Mario Pagliaro, Rosaria Ciriminna","doi":"10.1007/s10971-024-06512-8","DOIUrl":"https://doi.org/10.1007/s10971-024-06512-8","url":null,"abstract":"<p>Showing broad scope pesticidal properties, the <i>Origanum vulgare</i> essential oil is highly volatile, limiting effective agricultural applications. Aiming to develop new environmentally friendly and effective biopesticide based on <i>O. vulgare</i> essential oil we carried out its template-assisted sol-gel microencapsulation within silica microcapsules. The method affords mesoporous SiO<sub>2</sub> spherical particles about 430 nm in size with uniform size distribution (polydispersion index of 0.184) having encapsulation efficiency up to 13.7 wt%, and large positive zeta potential of 22.8 mV. Dubbed herein “SiliOregan”, this new class of sol-gel materials is promising towards the development of solid biopesticides formulated in water for pest management against fungi, insects, bacteria, nematodes, and mites.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142225054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1007/s10971-024-06525-3
Fouad El Aychaoui, Abdelhalim El Basset, Mohamed Naji, Mohammed Bouzid, Abdelilah Rjeb, Lahoucine Hajji, Yahya Ababou
In this paper, we studied the effect of lithium doping on the structural, microstructural, dielectric, and electrical properties of Ba1-xLixTiO3-δ (BTLx) ceramics prepared via the sol-gel method, with x = 0, 0.01, 0.03, 0.05, 0.07 and 0.09. The results obtained from Rietveld refinement of X-ray diffraction, infrared spectroscopy, and Raman spectroscopy show that all the samples crystallize in the tetragonal phase. Dielectric measurements show that increasing the lithium doping rate results in lower dielectric losses (from 0.04 for x = 0 to 0.008 for x = 0.09 at room temperature) and lower transition temperature Tm for compositions with x ≤ 0.07. The phase transition diffusivity parameter γ varies between 1 and 1.39, showing that our samples exhibit a diffuse phase transition but far from relaxor behavior. Complex impedance spectroscopy indicates that the grain boundary resistance of the materials is predominant in the electrical behavior of the materials. The activation energy Ea was calculated at 10 kHz by linear fitting of the temperature dependence of conductivity using the Arrhenius formula. The obtained values indicate that conduction for compositions with 0 ≤ x ≤ 0.05 occurs through free electrons originating from the ionization of oxygen vacancies, while for the compositions with x = 0.07 and 0.09, the predominant conduction mechanism is ionic conduction.
Graphical Abstract
本文研究了锂掺杂对溶胶-凝胶法制备的 Ba1-xLixTiO3-δ (BTLx) 陶瓷（x = 0、0.01、0.03、0.05、0.07 和 0.09）的结构、微观结构、介电和电气性能的影响。通过对 X 射线衍射、红外光谱和拉曼光谱进行里特维尔德细化得出的结果表明，所有样品均为四方晶相。介电测量结果表明，增加锂掺杂率可降低介电损耗（室温下，从 x = 0 时的 0.04 到 x = 0.09 时的 0.008），并降低 x ≤ 0.07 时的转变温度 Tm。相变扩散参数 γ 在 1 到 1.39 之间变化，表明我们的样品表现出扩散相变，但远非弛豫行为。复阻抗光谱表明，材料的晶界电阻在材料的电学行为中占主导地位。活化能 Ea 是在 10 kHz 频率下通过使用阿伦尼乌斯公式对导电率的温度依赖性进行线性拟合计算得出的。所得数值表明，在 0 ≤ x ≤ 0.05 的成分中，传导是通过氧空位电离产生的自由电子进行的，而在 x = 0.07 和 0.09 的成分中，主要的传导机制是离子传导。
{"title":"Structural and enhanced dielectric properties of Li-doped BT elaborated by the sol-gel method","authors":"Fouad El Aychaoui, Abdelhalim El Basset, Mohamed Naji, Mohammed Bouzid, Abdelilah Rjeb, Lahoucine Hajji, Yahya Ababou","doi":"10.1007/s10971-024-06525-3","DOIUrl":"https://doi.org/10.1007/s10971-024-06525-3","url":null,"abstract":"<p>In this paper, we studied the effect of lithium doping on the structural, microstructural, dielectric, and electrical properties of Ba<sub>1-x</sub>Li<sub>x</sub>TiO<sub>3-δ</sub> (BTLx) ceramics prepared via the sol-gel method, with x = 0, 0.01, 0.03, 0.05, 0.07 and 0.09. The results obtained from Rietveld refinement of X-ray diffraction, infrared spectroscopy, and Raman spectroscopy show that all the samples crystallize in the tetragonal phase. Dielectric measurements show that increasing the lithium doping rate results in lower dielectric losses (from 0.04 for x = 0 to 0.008 for x = 0.09 at room temperature) and lower transition temperature Tm for compositions with x ≤ 0.07. The phase transition diffusivity parameter γ varies between 1 and 1.39, showing that our samples exhibit a diffuse phase transition but far from relaxor behavior. Complex impedance spectroscopy indicates that the grain boundary resistance of the materials is predominant in the electrical behavior of the materials. The activation energy Ea was calculated at 10 kHz by linear fitting of the temperature dependence of conductivity using the Arrhenius formula. The obtained values indicate that conduction for compositions with 0 ≤ x ≤ 0.05 occurs through free electrons originating from the ionization of oxygen vacancies, while for the compositions with x = 0.07 and 0.09, the predominant conduction mechanism is ionic conduction.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":664,"journal":{"name":"Journal of Sol-Gel Science and Technology","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142195933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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