APPLIED SURFACE SCIENCE
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2023
·
IF 6.7
Wei-qing An,Xiang-an Yue,Ji-rui Zou,Li-juan Zhang,Rong-jie Yan
In this study, we investigate the properties and behavior of interfacial water on solid silica surfaces and its implications for various applications. We utilize a combination of transmission electron microscopy (TEM), nuclear magnetic resonance, mass spectrometry, infrared, and Raman spectroscopy to explore the presence and characteristics of anomalous water on silica surfaces. Our findings reveal a stable, nanoscale layer of wall-bound water on the inner surface of silica tubes that persists under high vacuum and room temperature conditions. This layer is rich in hydrated hydrogen ions and exhibits a thickness that correlates with the density of hydroxyl groups in silica. Through additional experimentation, we demonstrate that reducing the density of silica hydroxyl groups causes the wall-bound water to return to a liquid state, highlighting the pivotal role of hydroxyl groups in the formation of this unique water layer. Our study offers valuable insights into the properties and behavior of interfacial water on solid surfaces and lays the foundation for potential applications in a wide range of fields, such as energy storage, drug delivery, environmental remediation, biological sample preparation, microfluidics, and nanofluidics. Future research will further explore the properties and behavior of interfacial water on different material surfaces and under various environmental conditions, laying the groundwork for technological innovation in related fields. By utilizing advanced approaches and fostering interdisciplinary collaboration, this research contributes significantly to our understanding of interfacial water and paves the way for the development of cutting-edge technologies that capitalize on its distinctive properties.
研究领域:
材料科学
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表面化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Fengshou Yu,Zhixiang Zhou,Yang You,Jiayu Zhan,Tong Yao,Lu-Hua Zhang
Precise electronic state regulation through coordination environment optimization by metal–support interaction is a promising strategy to facilitate catalysis reaction, while the limited density of functional groups in the bulk substrate restricts the regulation degree. Herein, different sizes of Ti3C2Tx MXene with hydroxyl (−OH) terminal including the MXene layer (ML-OH, 3 μm), the MXene nanosheet (MNS-OH, 600 nm), and the MXene quantum dot (MQD-OH, 8 nm) were prepared to anchor CoPc, and the effect of −OH density on the performance of electrochemical CO2 reduction was systematically investigated. Notably, a linear relationship was established by plotting reactivity vs hydroxyl density. With the highest −OH density, CoPc/MQD-OH exhibits a superior Faradaic efficiency for CO formation (FECO) of ∼100% at −0.9 to −1.0 V vs RHE and a high FECO of >90% over a wide potential window from −0.8 to −1.4 V. The mechanism exploration shows that the axial coordination interaction of the −OH terminal with Co increases the electron density of the Co site, thus promoting the adsorption and activation of CO2. This work provides a new insight into designing of molecular catalysts with high efficiency and tunable structure for other electrochemical conversions.
研究领域:
材料科学
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电化学
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催化反应
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NANOTECHNOLOGY
·
2024
·Vol. 35
·期 12
·125601
·
IF 2.9
Xia Pu,Wanling Cai,Huayao Chen,Fujie Yang,Xiaomei Mu
The key step in preparing mesoporous silica is to remove the organic template agent, and the most common method used to achieve this goal is high-temperature calcination. However, this method has many disadvantages, one of which is that it reduces the silanol density on the surface of mesoporous silica, which affects its subsequent modification. Ionic liquids (ILs) are often used as extractants. In this work, the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) IL is considered, and the effects of its concentration, reaction temperature, and reaction time as well as HCl concentration on the extraction rate and silanol density were investigated using an IL extraction template agent (cetyl trimethyl ammonium bromide (CTAB)). The results show that an IL concentration of 10%, a reaction temperature of 120 °C, a reaction time of 12 h, and an HCl concentration of 1% are the best reaction parameters; with these parameters, the extraction rate and the silanol density were found to be 93.19% and 2.23%, respectively. The silanol density of mesoporous silica treated by calcination is only 0.81%. A higher silanol density provides more reaction sites, so that the modified mesoporous silica treated with the IL can be loaded with more Zn ions.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Scientific Reports
·
2024
·Vol. 14
·期 1
·1-12
·
IF 3.8
Niu Yanhui,Yu Wenbin,Yang Shuguang,Wan Quan
This research delved into the influence of mesoporous silica’s surface charge density on the adsorption of Cu 2+ . The synthesis of mesoporous silica employed the hydrothermal method, with pore size controlled by varying the length of trimethylammonium bromide (C n TAB, n = 12, 14, 16) chains. Gas adsorption techniques and transmission electron microscopy characterized the mesoporous silica structure. Surface charge densities of the mesoporous silica were determined through potentiometric titration, while surface hydroxyl densities were assessed using the thermogravimetric method. Subsequently, batch adsorption experiments were conducted to study the adsorption of Cu 2+ in mesoporous silica, and the process was comprehensively analyzed using Atomic absorption spectrometry (AAS), Fourier transform infrared (FTIR), and L3 edge X-ray absorption near edge structure (XANES). The research findings suggest a positive correlation between the pore size of mesoporous silica, its surface charge density, and the adsorption capacity for Cu 2+ . More specifically, as the pore size increases within the 3–4.1 nm range, the surface charge density and the adsorption capacity for Cu 2+ also increase. Our findings provide valuable insights into the relationship between the physicochemical properties of mesoporous silica and the adsorption behavior of Cu 2+ , offering potential applications in areas such as environmental remediation and catalysis.
研究领域:
材料科学
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环境科学
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化学
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Tingting Yan,Senlin Deng,Gang Wang,Jie Li,Wei Chang,Guoliang Zhang,Chunshan Li
Acid-base bifunctional Cs-Zr supported SiO 2 exhibit high catalytic performance on aldol condensation of methyl propionate (MP) and formaldehyde (FA) toward methyl acrylate (MMA). However, the effect of structural configuration of surface active sites on the formation rate and selectivity of MMA remains unclear. In this study, a surface engineering strategy was proposed to directionally induce the formation of catalytically active centers. Comprehensive characterizations were performed to identify the structural configuration of surface active Cs and Zr sites and their influence on MMA production in combination with catalytic evaluation. It was discovered that the increased density of isolated hydroxyl groups (≡Si-OH) on SiO 2 support after calcination treatment promoted the formation of well-defined Si-O-Zr and Si-O-Cs structures, corresponding to the medium strong acid and weak base sites. The acid-base properties and their balance of as-prepared Cs/Zr/SiO 2 catalyst could be controllably modulated by the surface hydroxyl density and Cs (Zr) loading. These highly dispersed Cs and Zr species generated through the strong interaction with hydroxyl groups facilitated the production of MMA while suppressed the undesired Methylacrolein (MAL). Consequentially, the formation rate and selectivity of MMA could reach up to 0.91 mmol/h/g Cat. and 94.3 % on the optimal 1.5Cs/0.25Zr/SiO 2 catalyst. Further mechanistic studies using In-situ DRIFT revealed the catalytic pathway toward MMA and MAL, confirming the activation of MP was the kinetic-relevant step.
研究领域:
催化化学
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材料化学
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表面科学
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有机合成
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工业催化
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2022
·
IF 6.057
Pengcheng Miao,Xuefei Leng,Jie Liu,Guanjun Song,Maomao He,Yang Li
The dynamic behaviors of vitrimer are influenced by the interaction of cross-link density and density of exchangeable groups, which results in the difficulty of extracting the effect of mono-variation. In this study, the dynamic behaviors of vitrimer were tuned by changing the density of exchangeable hydroxyls alone, while leaving the cross-link density undisturbed. A multi-hydroxy vitrimer network without a loading catalyst was synthesized successfully. Three-armed functionalized polycarbonate, obtained by ring-opening polymerization of 1,3-dioxan-2-one and its derivatives, was treated as a precursor polymer. Afterward, the precursor polymer was converted into vitrimer in a single step by treatment with hexamethylene diisocyanate. When the system with constant cross-link density was established, the accurate effect of the hydroxyl density on the dynamic behaviors could be characterized by stress relaxation. The relationship of essential dynamic behavioral parameters, such as topology freezing transition temperature (Tv), exchange activation energy (Ea), and Arrhenius prefactor (τ0), with the density of exchangeable hydroxyls was quantitatively discussed. The results indicated that Tv and Ea were negatively correlated with the density of exchangeable hydroxyls, while τ0 showed a positive correlation. In addition, linear models were developed to describe the relationship between dynamic behaviors of vitrimer and density of exchangeable hydroxyls. It is expected that the findings can be applied to precisely control Ea, τ0, Tv, and characteristic relaxation time (τ*) of vitrimer and can also be used as a model for the synthesis of various vitrimer materials.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）