Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency and selectivity. In this study, we correlated the macroscopic behavior of the Zr(IV) extraction from nitric acid solutions with microscopic structural information to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system as compared to the analogous organic extraction system. The fluorous and organic extraction systems consist of tris(4,4,5,5,6,6,7,7,7-nonafluoroheptyl) phosphate (TFP) in perfluorohexane and tri-n-heptyl phosphate (THP) in n-hexane, respectively. Extended X-ray absorption fine structure, neutron reflectometry (NR), and small-angle neutron scattering revealed the structural information around the central metal ion of the complex, at the interface, and in the bulk extraction phase, respectively. NR results showed that extractant molecules did not accumulate much at the interface in both extraction system. In the fluorous extraction system, extractant aggregates with a 1.46 nm radius of gyration (Rg) were formed after contact with nitric acid, and remained even after Zr(IV) extraction through the form of a 1:3 (Zr(IV):TFP) complex. In contrast, in the organic extraction system, only extractant dimers with Rg of 0.70 nm were formed and Zr(IV) is extracted through the form of a 1:2 (Zr(IV):THP) complex. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.
{"title":"Fluorous and Organic Extraction Systems: A Comparison from the Perspectives of Coordination Structures, Interfaces, and Bulk Extraction Phases.","authors":"Yuki Ueda, Cyril Micheau, Kazuhiro Akutsu-Suyama, Kohei Tokunaga, Masako Yamada, Norifumi L Yamada, Damien Bourgeois, Ryuhei Motokawa","doi":"10.1021/acs.langmuir.4c02268","DOIUrl":"10.1021/acs.langmuir.4c02268","url":null,"abstract":"<p><p>Microscopic structures in liquid-liquid extraction, such as structuration between extractants or extracted complexes in bulk organic phases and at interfaces, can influence macroscopic phenomena, such as the distribution behavior of solutes, including extraction efficiency and selectivity. In this study, we correlated the macroscopic behavior of the Zr(IV) extraction from nitric acid solutions with microscopic structural information to understand at the molecular level the key factors contributing to the higher metal ion extraction performance in the fluorous extraction system as compared to the analogous organic extraction system. The fluorous and organic extraction systems consist of tris(4,4,5,5,6,6,7,7,7-nonafluoroheptyl) phosphate (TFP) in perfluorohexane and tri-<i>n</i>-heptyl phosphate (THP) in <i>n</i>-hexane, respectively. Extended X-ray absorption fine structure, neutron reflectometry (NR), and small-angle neutron scattering revealed the structural information around the central metal ion of the complex, at the interface, and in the bulk extraction phase, respectively. NR results showed that extractant molecules did not accumulate much at the interface in both extraction system. In the fluorous extraction system, extractant aggregates with a 1.46 nm radius of gyration (<i>R</i><sub>g</sub>) were formed after contact with nitric acid, and remained even after Zr(IV) extraction through the form of a 1:3 (Zr(IV):TFP) complex. In contrast, in the organic extraction system, only extractant dimers with <i>R</i><sub>g</sub> of 0.70 nm were formed and Zr(IV) is extracted through the form of a 1:2 (Zr(IV):THP) complex. We speculate that differences in the local coordination structure around the Zr(IV) ion and the structuration of the extractant molecules in the bulk extraction phase contribute to the high Zr(IV) extraction performance in the fluorous extraction system. In particular, the size of the aggregates hardly changed with increasing Zr(IV) concentration in the fluorous phase, which may be closely related to the absence of phase splitting in the fluorous extraction system.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1021/acs.langmuir.4c02686
Luyao Duan, Junfei Zhang, Guowei Ma, Zhu Pan
Graphene oxide (GO) enhances the performance of cement-based materials by optimizing the microstructure of calcium-silicate-hydrate (C–S–H). However, the influence of GO on the nucleation and growth of C–S–H gel at nanoscale is unexplored. This study investigates this mechanism by molecular dynamics simulation at nano scale. Results show that GO can reduce the activation energy during the polymerization reaction of silicon oxide tetrahedra during the reaction process, and can increase the content of polymer Q3 and Q4. The influence of GO with epoxy (–O−), hydroxyl (−OH) and carboxyl (−COOH) groups on the radial distribution function (RDF), mean square displacement (MSD), and atomic spatial distribution of monomers are studied. Results show that GO–OH exhibits excellent performance, with the highest number of bridging oxygen atoms (about 0.6), the lowest Q0 monomer content (just 26.8%), the highest RDF (27.18), and the highest MSD (calcium and silicon content around 20,000 Å2). This paper elucidates the nucleation and growth mechanism of C–S–H influenced by GO to develop high performance cement.
{"title":"Graphene Oxide-Enhanced Nucleation and Growth of Calcium-Silicate-Hydrate Gel at Nanoscale: A Molecular Dynamics Study","authors":"Luyao Duan, Junfei Zhang, Guowei Ma, Zhu Pan","doi":"10.1021/acs.langmuir.4c02686","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02686","url":null,"abstract":"Graphene oxide (GO) enhances the performance of cement-based materials by optimizing the microstructure of calcium-silicate-hydrate (C–S–H). However, the influence of GO on the nucleation and growth of C–S–H gel at nanoscale is unexplored. This study investigates this mechanism by molecular dynamics simulation at nano scale. Results show that GO can reduce the activation energy during the polymerization reaction of silicon oxide tetrahedra during the reaction process, and can increase the content of polymer Q<sub>3</sub> and Q<sub>4</sub>. The influence of GO with epoxy (–O−), hydroxyl (−OH) and carboxyl (−COOH) groups on the radial distribution function (RDF), mean square displacement (MSD), and atomic spatial distribution of monomers are studied. Results show that GO–OH exhibits excellent performance, with the highest number of bridging oxygen atoms (about 0.6), the lowest Q<sub>0</sub> monomer content (just 26.8%), the highest RDF (27.18), and the highest MSD (calcium and silicon content around 20,000 Å<sup>2</sup>). This paper elucidates the nucleation and growth mechanism of C–S–H influenced by GO to develop high performance cement.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1021/acs.langmuir.4c02978
Sapana Sinha, Sagar Srivastava, Vinod K. Aswal, Debabrata Seth
Fundamental investigations into the photophysical properties and microenvironmental features of pluronic–zwitterionic surfactant mixed assemblies are essential for advancing our understanding of molecular interactions at the nanoscale, setting the stage for innovative solutions in drug delivery, diagnostics, and other applications of pluronic–zwitterionic surfactant assemblies. This investigation explores the intricate photophysics of pluronic–zwitterionic surfactant mixed assemblies, utilizing the twisted intramolecular charge transfer state forming styryl dye trans-2-[(4-dimethylamino) styryl] benzothiazole as a probe. By comparing the behaviors of two distinct poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) block copolymers with block composition of (PEO)132-(PPO)50-(PEO)132 [F108] and (PEO)100-(PPO)65-(PEO)100 [F127] at concentrations of 5 and 10 wt %, this study systematically examines the impact of the addition of zwitterionic surfactants. Through a comprehensive set of analytical techniques, including UV–visible absorption, steady-state emission, and time-resolved fluorescence emission studies, significant alterations in the emission spectra and quantum yields were observed upon the addition of zwitterionic surfactants. These modifications suggest a dynamic equilibrium for the transitioning of dye molecules between various microenvironments within the assemblies. Additionally, dynamic light scattering, zeta potential (ζ), nuclear Overhauser effect spectroscopy, small-angle neutron scattering, cryogenic transmission electron microscopy, field emission scanning electron microscopy, and fluorescence lifetime imaging microscopy analyses have shed light on the substantial impact of surfactant incorporation on the structural properties of assemblies.
{"title":"Deciphering the Influence of Zwitterionic Surfactants on Pluronic Co-assemblies: A Synergistic Odyssey through Spectroscopic, Microscopic, and Scattering Techniques","authors":"Sapana Sinha, Sagar Srivastava, Vinod K. Aswal, Debabrata Seth","doi":"10.1021/acs.langmuir.4c02978","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02978","url":null,"abstract":"Fundamental investigations into the photophysical properties and microenvironmental features of pluronic–zwitterionic surfactant mixed assemblies are essential for advancing our understanding of molecular interactions at the nanoscale, setting the stage for innovative solutions in drug delivery, diagnostics, and other applications of pluronic–zwitterionic surfactant assemblies. This investigation explores the intricate photophysics of pluronic–zwitterionic surfactant mixed assemblies, utilizing the twisted intramolecular charge transfer state forming styryl dye trans-2-[(4-dimethylamino) styryl] benzothiazole as a probe. By comparing the behaviors of two distinct poly(ethylene oxide)-<i>block</i>-poly(propylene oxide)-<i>block</i>-poly(ethylene oxide) block copolymers with block composition of (PEO)<sub>132-</sub>(PPO)<sub>50</sub>-(PEO)<sub>132</sub> [F108] and (PEO)<sub>100</sub>-(PPO)<sub>65</sub>-(PEO)<sub>100</sub> [F127] at concentrations of 5 and 10 wt %, this study systematically examines the impact of the addition of zwitterionic surfactants. Through a comprehensive set of analytical techniques, including UV–visible absorption, steady-state emission, and time-resolved fluorescence emission studies, significant alterations in the emission spectra and quantum yields were observed upon the addition of zwitterionic surfactants. These modifications suggest a dynamic equilibrium for the transitioning of dye molecules between various microenvironments within the assemblies. Additionally, dynamic light scattering, zeta potential (ζ), nuclear Overhauser effect spectroscopy, small-angle neutron scattering, cryogenic transmission electron microscopy, field emission scanning electron microscopy, and fluorescence lifetime imaging microscopy analyses have shed light on the substantial impact of surfactant incorporation on the structural properties of assemblies.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nature-inspired, robust, durable, liquid-repellent interfaces have attracted considerable interest in the field of wood biomimetic intelligence science and technology application. However, realizing green environmental protection and low maintenance and replacement cost wood surfaces constructed with micro/nanoarchitectures is not an easy task. Aiming at the problem of poor waterproof performance of wood, a silicon dioxide/polydimethylsiloxane (SiO2/PDMS) self-cleaning programmable superhydrophobic coating was biomimetically constructed on the wood substrate by surface-embedded dual-dipping design based on the "substrates + nanoparticles" hybrid principle of the lotus leaf effect. This robust, durable, nature-inspired, self-cleaning, programmable superhydrophobic coating was found to have no observable impact on the original color and texture of the natural wood. The SiO2/PDMS/wood prepared exhibited exceptional liquid repellency and a high static water contact angle (WCA) of 158.5° and a low slide angle (SA) of 10°, including everyday general-purpose droplets, indicating that the introduction of the monodisperse SiO2 microspheres can effectively enhance the superhydrophobic properties of the hydrophilic wood. We applied this strategy to a variety of substrates, including wood-cellulose aerogel and wood-cellulose paper, and demonstrated that the liquid-repellent nature of the self-cleaning superhydrophobic coating remained unchanged. Moreover, the superhydrophobic surface of SiO2/PDMS/wood was preserved even after harsh abrasion conditions, including mechanical damage (sandpaper, sharp steel blade, and tapes), thermal damage (UV irradiation and low/high-temperature exposure such as steaming and freezing), chemical damage, and solvent corrosion (immersion in acid, alkali), demonstrating robust stability of the superhydrophobic coating. Furthermore, the SiO2/PDMS programmable superhydrophobic coating exhibits exceptional exciting self-cleaning and stain-resistant properties, making it offer greater possibilities in terms of scientific challenges and real-world problem-solving at biomimetic smart superhydrophobic interfaces in wood.
{"title":"Wood Surface-Embedding of Functional Monodisperse SiO<sub>2</sub> Microspheres for Achieving Robust, Durable, Nature-Inspired, Programmable Superrepellent Interfaces.","authors":"Huajie Shen, Kangkang Zhang, Donghai Huang, Yuan Miao, Caipin Lian, Xinzhen Zhuo","doi":"10.1021/acs.langmuir.4c03178","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03178","url":null,"abstract":"<p><p>Nature-inspired, robust, durable, liquid-repellent interfaces have attracted considerable interest in the field of wood biomimetic intelligence science and technology application. However, realizing green environmental protection and low maintenance and replacement cost wood surfaces constructed with micro/nanoarchitectures is not an easy task. Aiming at the problem of poor waterproof performance of wood, a silicon dioxide/polydimethylsiloxane (SiO<sub>2</sub>/PDMS) self-cleaning programmable superhydrophobic coating was biomimetically constructed on the wood substrate by surface-embedded dual-dipping design based on the \"substrates + nanoparticles\" hybrid principle of the lotus leaf effect. This robust, durable, nature-inspired, self-cleaning, programmable superhydrophobic coating was found to have no observable impact on the original color and texture of the natural wood. The SiO<sub>2</sub>/PDMS/wood prepared exhibited exceptional liquid repellency and a high static water contact angle (WCA) of 158.5° and a low slide angle (SA) of 10°, including everyday general-purpose droplets, indicating that the introduction of the monodisperse SiO<sub>2</sub> microspheres can effectively enhance the superhydrophobic properties of the hydrophilic wood. We applied this strategy to a variety of substrates, including wood-cellulose aerogel and wood-cellulose paper, and demonstrated that the liquid-repellent nature of the self-cleaning superhydrophobic coating remained unchanged. Moreover, the superhydrophobic surface of SiO<sub>2</sub>/PDMS/wood was preserved even after harsh abrasion conditions, including mechanical damage (sandpaper, sharp steel blade, and tapes), thermal damage (UV irradiation and low/high-temperature exposure such as steaming and freezing), chemical damage, and solvent corrosion (immersion in acid, alkali), demonstrating robust stability of the superhydrophobic coating. Furthermore, the SiO<sub>2</sub>/PDMS programmable superhydrophobic coating exhibits exceptional exciting self-cleaning and stain-resistant properties, making it offer greater possibilities in terms of scientific challenges and real-world problem-solving at biomimetic smart superhydrophobic interfaces in wood.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1021/acs.langmuir.4c03507
Liming Zeng, Bang Yuan, Qing Zhou
Oxygen evolution reaction (OER) is a multistep proton-coupled four-electron process with sluggish kinetics, which seriously limits the hydrogen production efficiency, thus it is of great importance to develop an efficient and stable OER catalyst. In this study, a two-step differential pyrolysis strategy is employed to design a three-dimensional porous microstructured material consisting of RuOx nanoparticles coated by a thin-layer carbon, where the active particles were isolated in separate chambers and the RuOx nanoparticles mainly existed in the form of a heterogeneous interface between RuO2 and partial metallic Ru. The preparation parameters of the catalysts are optimized via combining transient and steady-state polarization properties, and the target catalyst Cat-500–1.5t shows the best OER catalytic performance after ca. 60 h of a chronopotentiometry test in an acidic medium with a much smaller performance change than other samples. The unique design of adopting a carbon layer to form separate reaction chambers largely mitigates the excessive oxidation loss of the active components under strong oxidation potential. The suitability of the catalyst with the loaded substrate and test media is explored, and in an acidic medium, the carbon paper is much better than the titanium fiber, while in an alkaline medium, the titanium fiber is obviously superior to the carbon paper. On both carbon paper and titanium fiber, the performance in an alkaline medium outperforms that in an acidic medium, and the possible reasons for the performance difference are analyzed. Herein, to obtain the actual electrocatalytic performance, the optimal design of the catalyst structure and matching suitable conductive substrate in a specific medium are quite necessary, which provides a feasible strategy for the acquisition of efficient and stable electrocatalysts and the desirable presentation of performance.
氧进化反应(OER)是一个多步骤质子耦合四电子过程,其动力学缓慢,严重限制了制氢效率,因此开发一种高效稳定的 OER 催化剂具有重要意义。本研究采用两步差热分解策略设计了一种由纳米 RuOx 粒子包覆薄层碳组成的三维多孔微结构材料,其中活性粒子被隔离在不同的腔室中,纳米 RuOx 粒子主要以 RuO2 和部分金属 Ru 的异质界面形式存在。通过结合瞬态和稳态极化特性,对催化剂的制备参数进行了优化,目标催化剂 Cat-500-1.5t 在经过约 60 h 的慢动作催化后显示出最佳的 OER 催化性能。目标催化剂 Cat-500-1.5t 在酸性介质中经过约 60 小时的计时电位测试后,显示出最佳的 OER 催化性能,其性能变化远远小于其他样品。采用碳层形成独立反应室的独特设计在很大程度上减轻了活性成分在强氧化电位下的过度氧化损失。在酸性介质中,碳纸的性能远优于钛纤维,而在碱性介质中,钛纤维则明显优于碳纸。碳纸和钛纤维在碱性介质中的性能均优于酸性介质,并分析了造成性能差异的可能原因。由此可见,要获得实际的电催化性能,催化剂结构的优化设计和在特定介质中匹配合适的导电基底是十分必要的,这为获得高效稳定的电催化剂和理想的性能表现提供了可行的策略。
{"title":"Enabling Efficient Oxygen Evolution via Anchoring Carbon-Layer-Confined RuOx on a Well-Matched Substrate","authors":"Liming Zeng, Bang Yuan, Qing Zhou","doi":"10.1021/acs.langmuir.4c03507","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03507","url":null,"abstract":"Oxygen evolution reaction (OER) is a multistep proton-coupled four-electron process with sluggish kinetics, which seriously limits the hydrogen production efficiency, thus it is of great importance to develop an efficient and stable OER catalyst. In this study, a two-step differential pyrolysis strategy is employed to design a three-dimensional porous microstructured material consisting of RuO<sub><i>x</i></sub> nanoparticles coated by a thin-layer carbon, where the active particles were isolated in separate chambers and the RuO<sub><i>x</i></sub> nanoparticles mainly existed in the form of a heterogeneous interface between RuO<sub>2</sub> and partial metallic Ru. The preparation parameters of the catalysts are optimized via combining transient and steady-state polarization properties, and the target catalyst Cat-500–1.5<i>t</i> shows the best OER catalytic performance after ca. 60 h of a chronopotentiometry test in an acidic medium with a much smaller performance change than other samples. The unique design of adopting a carbon layer to form separate reaction chambers largely mitigates the excessive oxidation loss of the active components under strong oxidation potential. The suitability of the catalyst with the loaded substrate and test media is explored, and in an acidic medium, the carbon paper is much better than the titanium fiber, while in an alkaline medium, the titanium fiber is obviously superior to the carbon paper. On both carbon paper and titanium fiber, the performance in an alkaline medium outperforms that in an acidic medium, and the possible reasons for the performance difference are analyzed. Herein, to obtain the actual electrocatalytic performance, the optimal design of the catalyst structure and matching suitable conductive substrate in a specific medium are quite necessary, which provides a feasible strategy for the acquisition of efficient and stable electrocatalysts and the desirable presentation of performance.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1021/acs.langmuir.4c02908
Lucile Bisquert, Élfego Ruiz-Gutiérrez, Marc Pradas, Rodrigo Ledesma-Aguilar
The shape and stability of a droplet in contact with a solid surface is affected by the chemical composition and topography of the solid, and crucially, by the droplet's size. During a variation in size, most often observed during evaporation, droplets on smooth patterned surfaces can undergo sudden shape and position changes. Such changes, called snaps, are prompted by the surface pattern and arise from fold and pitchfork bifurcations which respectively cause symmetric and asymmetric motions. Yet, which type of snap is likely to be observed is an open fundamental question that has relevance in the rational design of surfaces for managing droplets. Here we show that the likelihood of observing symmetric or asymmetric snaps depends on the distance between fold and pitchfork bifurcation points and on how this distance varies for droplets that grow or shrink in size on surfaces patterned with a smooth topography. Our results can help develop strategies to control droplets by exploiting smooth surface patterns but also have broader relevance in situations where different types of bifurcations compete in determining the stability of a system, for instance in snap-through instabilities observed in elastic media.
{"title":"Competing Bifurcations Determine Symmetry Breaking During Droplet Snaps on Smooth Patterned Surfaces.","authors":"Lucile Bisquert, Élfego Ruiz-Gutiérrez, Marc Pradas, Rodrigo Ledesma-Aguilar","doi":"10.1021/acs.langmuir.4c02908","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c02908","url":null,"abstract":"<p><p>The shape and stability of a droplet in contact with a solid surface is affected by the chemical composition and topography of the solid, and crucially, by the droplet's size. During a variation in size, most often observed during evaporation, droplets on smooth patterned surfaces can undergo sudden shape and position changes. Such changes, called snaps, are prompted by the surface pattern and arise from fold and pitchfork bifurcations which respectively cause symmetric and asymmetric motions. Yet, which type of snap is likely to be observed is an open fundamental question that has relevance in the rational design of surfaces for managing droplets. Here we show that the likelihood of observing symmetric or asymmetric snaps depends on the distance between fold and pitchfork bifurcation points and on how this distance varies for droplets that grow or shrink in size on surfaces patterned with a smooth topography. Our results can help develop strategies to control droplets by exploiting smooth surface patterns but also have broader relevance in situations where different types of bifurcations compete in determining the stability of a system, for instance in snap-through instabilities observed in elastic media.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Urea oxidation reaction (UOR) is an attractive alternative anodic reaction to oxygen evolution reaction (OER) for its low thermodynamic potential (0.37 V vs RHE). A major challenge that prohibits its practical application is the six-electron transfer process during UOR, demanding enhancements in the catalytic activity. Herein, a Fe-doped Ni3S2 catalyst with a uniform flower-like structure is synthesized in situ on nickel foam via a simple one-step hydrothermal method. The electrochemical properties of Fe-Ni3S2 are significantly improved since a current density of 10 mA cm-2 only requires a 1.33 V potential and remains stable for 60 h. The structural characterization demonstrates a strong interaction between Fe and Ni3S2. After Fe doping, the active site increases, which promotes the formation of NiOOH on the catalyst surface, thus speeding up the UOR process. These changes are beneficial to charge transfer and optimize the adsorption energy of the intermediates. In situ EIS further confirms that Fe promotes electron transfer during the UOR process, reduces the interface resistance between the catalyst and the electrolyte, and lowers the driving voltage.
尿素氧化反应(UOR)的热力学电位较低(0.37 V 对 RHE),是氧进化反应(OER)的一种有吸引力的替代阳极反应。阻碍其实际应用的一个主要挑战是 UOR 反应过程中的六电子转移过程,这就要求提高催化活性。本文通过简单的一步水热法,在泡沫镍上原位合成了具有均匀花状结构的掺铁 Ni3S2 催化剂。由于 10 mA cm-2 的电流密度只需要 1.33 V 的电位,且能保持稳定 60 小时,Fe-Ni3S2 的电化学性能得到了显著改善。掺入 Fe 后,活性位点增加,促进了催化剂表面 NiOOH 的形成,从而加快了 UOR 过程。这些变化有利于电荷转移,并优化了中间产物的吸附能。原位 EIS 进一步证实,铁在 UOR 过程中促进了电子转移,降低了催化剂与电解质之间的界面电阻,并降低了驱动电压。
{"title":"Fe-Doped Ni<sub>3</sub>S<sub>2</sub> Induces Self-Reconstruction for Urea-Assisted Water Electrolysis Enhancement.","authors":"Xinyu Yang, Yifeng Liu, Qianqiao Chen, Wanchin Yu, Qin Zhong","doi":"10.1021/acs.langmuir.4c03343","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03343","url":null,"abstract":"<p><p>Urea oxidation reaction (UOR) is an attractive alternative anodic reaction to oxygen evolution reaction (OER) for its low thermodynamic potential (0.37 V vs RHE). A major challenge that prohibits its practical application is the six-electron transfer process during UOR, demanding enhancements in the catalytic activity. Herein, a Fe-doped Ni<sub>3</sub>S<sub>2</sub> catalyst with a uniform flower-like structure is synthesized <i>in situ</i> on nickel foam via a simple one-step hydrothermal method. The electrochemical properties of Fe-Ni<sub>3</sub>S<sub>2</sub> are significantly improved since a current density of 10 mA cm<sup>-2</sup> only requires a 1.33 V potential and remains stable for 60 h. The structural characterization demonstrates a strong interaction between Fe and Ni<sub>3</sub>S<sub>2</sub>. After Fe doping, the active site increases, which promotes the formation of NiOOH on the catalyst surface, thus speeding up the UOR process. These changes are beneficial to charge transfer and optimize the adsorption energy of the intermediates. <i>In situ</i> EIS further confirms that Fe promotes electron transfer during the UOR process, reduces the interface resistance between the catalyst and the electrolyte, and lowers the driving voltage.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142580895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1021/acs.langmuir.4c03844
Su Dan Bao, Agula Bao
Previous research has proven that the pore shape and nitrogen group content of adsorbents play essential roles in determining their carbon dioxide (CO2) adsorption performance. In this article, a series of nitrogen-doped porous carbon materials were prepared for CO2 adsorption by varying the proportion of carbon nitride, the pyrolysis temperature, and the activation ratio of KOH, using chitosan as the carbon source, carbon nitride (g-C3N4 and g-C3N5) as self-sacrificing templating agents, and KOH as the activator. Among the prepared materials, T6-850-1 has the highest specific surface area (SBET) of 2336 m2/g, and T6-750-1 has the highest microporous area (Smicro) and CO2 adsorption capacity (1 bar, 298 K) of 1969 m2/g and 3.49 mmol/g, respectively. The thermal decomposition temperature and products of carbon nitride templates were characterized and tested by thermogravimetric infrared gas chromatography-mass spectrometry (TG-IR-GC-MS), and the thermal decomposition mechanisms of the two carbon nitride templates were investigated. We found that the thermal stability of the template directly affects the pore structure of the final sample as well as the type and quantity of nitrogen species.
{"title":"Regulating the Performance of CO2 Adsorbents Based on the Pyrolysis Mechanism of Self-Sacrificial Templating Agents","authors":"Su Dan Bao, Agula Bao","doi":"10.1021/acs.langmuir.4c03844","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03844","url":null,"abstract":"Previous research has proven that the pore shape and nitrogen group content of adsorbents play essential roles in determining their carbon dioxide (CO<sub>2</sub>) adsorption performance. In this article, a series of nitrogen-doped porous carbon materials were prepared for CO<sub>2</sub> adsorption by varying the proportion of carbon nitride, the pyrolysis temperature, and the activation ratio of KOH, using chitosan as the carbon source, carbon nitride (g-C<sub>3</sub>N<sub>4</sub> and g-C<sub>3</sub>N<sub>5</sub>) as self-sacrificing templating agents, and KOH as the activator. Among the prepared materials, T6-850-1 has the highest specific surface area (<i>S</i><sub>BET</sub>) of 2336 m<sup>2</sup>/g, and T6-750-1 has the highest microporous area (<i>S</i><sub>micro</sub>) and CO<sub>2</sub> adsorption capacity (1 bar, 298 K) of 1969 m<sup>2</sup>/g and 3.49 mmol/g, respectively. The thermal decomposition temperature and products of carbon nitride templates were characterized and tested by thermogravimetric infrared gas chromatography-mass spectrometry (TG-IR-GC-MS), and the thermal decomposition mechanisms of the two carbon nitride templates were investigated. We found that the thermal stability of the template directly affects the pore structure of the final sample as well as the type and quantity of nitrogen species.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1021/acs.langmuir.4c03474
Mudasira Bhurt, Xin Li, Nan Zhang, Wenqi Yang, Muzhe Xu, Yang Liu, Yejiong Yu, Bingbing Sun
Aluminum-based adjuvants have been indispensable to vaccine potency. However, their effectiveness is difficult to maintain after freeze-drying, which limits the storage and application of aluminum-adjuvanted vaccines. In this study, the impact of freeze-drying on aluminum oxyhydroxide nanorods (AlOOH NRs) was investigated. Freeze-drying led to aggregation and resulted in the loss of the surface hydroxyl content of aluminum adjuvants. To alleviate freeze-drying-induced damage, the potency of different alkyl glycosides as protectants was further evaluated. It was demonstrated that the structural balance of the head and tail of a glycoside was more conducive to protecting AlOOH NRs from aggregation and loss of surface hydroxyl groups. These results underline the proper selection of protectants to protect adjuvants against functional defects caused by freeze-drying, which is important for the stability and efficacy of vaccines and biopharmaceutical products.
铝基佐剂对疫苗的效力不可或缺。然而,铝佐剂在冷冻干燥后很难保持其有效性,这限制了铝佐剂疫苗的储存和应用。本研究调查了冻干对氧化铝纳米棒(AlOOH NRs)的影响。冷冻干燥会导致铝佐剂表面羟基的聚集和损失。为了减轻冻干引起的损伤,研究人员进一步评估了不同烷基糖苷作为保护剂的功效。结果表明,糖苷头部和尾部的结构平衡更有利于保护 AlOOH NR 免受聚集和表面羟基的损失。这些结果强调了正确选择保护剂以保护佐剂免受冷冻干燥造成的功能缺陷的影响,这对疫苗和生物制药产品的稳定性和功效非常重要。
{"title":"Glycoside-Mediated Enhancement of Stability in Aluminum Oxyhydroxide Nanoadjuvants during Freeze-Drying","authors":"Mudasira Bhurt, Xin Li, Nan Zhang, Wenqi Yang, Muzhe Xu, Yang Liu, Yejiong Yu, Bingbing Sun","doi":"10.1021/acs.langmuir.4c03474","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03474","url":null,"abstract":"Aluminum-based adjuvants have been indispensable to vaccine potency. However, their effectiveness is difficult to maintain after freeze-drying, which limits the storage and application of aluminum-adjuvanted vaccines. In this study, the impact of freeze-drying on aluminum oxyhydroxide nanorods (AlOOH NRs) was investigated. Freeze-drying led to aggregation and resulted in the loss of the surface hydroxyl content of aluminum adjuvants. To alleviate freeze-drying-induced damage, the potency of different alkyl glycosides as protectants was further evaluated. It was demonstrated that the structural balance of the head and tail of a glycoside was more conducive to protecting AlOOH NRs from aggregation and loss of surface hydroxyl groups. These results underline the proper selection of protectants to protect adjuvants against functional defects caused by freeze-drying, which is important for the stability and efficacy of vaccines and biopharmaceutical products.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.9,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1021/acs.langmuir.4c03004
Reki Nakamoto, Hiroyuki Okazaki, Takanori Wakita, Takayoshi Yokoya, Yuji Muraoka
Film thickness is a well-known experimental parameter for controlling lattice strain in oxide films. However, due to environmental and resource conservation considerations, films need to be as thin as possible, increasing the need to find alternative factors for strain management. Herein, we present the importance of thermal energy as a factor for the formation of lattice strain in the oxide films, specifically focusing on the effects of laser fluence during pulsed laser deposition (PLD) on the in-plane lattice strain of vanadium dioxide (VO2) thin films grown on titanium dioxide (TiO2) (001). VO2 thin films were deposited using a KrF excimer laser (λ = 248 nm) at laser fluences ranging from 0.88 to 1.70 J/cm2. The film thickness ranged from 10-15 nm, below the critical thickness. Films grown at higher laser fluences exhibited smooth surfaces and completely strained in-plane lattices. In contrast, films grown at lower laser fluences displayed numerous small islands and relaxed in-plane lattice strain. The metal-insulator transition (MIT) temperature was lower for films grown at higher laser fluencies compared to those grown at lower laser fluences. It was also revealed that Ti-V interdiffusion occurs, forming a solid solution (V1-xTixO2) near the interface. These observations suggest that the thermal energy of the particles, influenced by laser fluence, is a critical factor in the formation of lattice strain in metal oxide films and also that laser fluence in PLD is an effective experimental parameter for strain management in oxide films. Our findings enhance the understanding of lattice strain formation in metal oxides and offer insights for establishing effective methods for controlling lattice strain in metal oxide films.
{"title":"Effects of Thermal Energy on the Formation of Lattice Strain in VO<sub>2</sub> Thin Films Grown on TiO<sub>2</sub>(001).","authors":"Reki Nakamoto, Hiroyuki Okazaki, Takanori Wakita, Takayoshi Yokoya, Yuji Muraoka","doi":"10.1021/acs.langmuir.4c03004","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c03004","url":null,"abstract":"<p><p>Film thickness is a well-known experimental parameter for controlling lattice strain in oxide films. However, due to environmental and resource conservation considerations, films need to be as thin as possible, increasing the need to find alternative factors for strain management. Herein, we present the importance of thermal energy as a factor for the formation of lattice strain in the oxide films, specifically focusing on the effects of laser fluence during pulsed laser deposition (PLD) on the in-plane lattice strain of vanadium dioxide (VO<sub>2</sub>) thin films grown on titanium dioxide (TiO<sub>2</sub>) (001). VO<sub>2</sub> thin films were deposited using a KrF excimer laser (λ = 248 nm) at laser fluences ranging from 0.88 to 1.70 J/cm<sup>2</sup>. The film thickness ranged from 10-15 nm, below the critical thickness. Films grown at higher laser fluences exhibited smooth surfaces and completely strained in-plane lattices. In contrast, films grown at lower laser fluences displayed numerous small islands and relaxed in-plane lattice strain. The metal-insulator transition (MIT) temperature was lower for films grown at higher laser fluencies compared to those grown at lower laser fluences. It was also revealed that Ti-V interdiffusion occurs, forming a solid solution (V<sub>1-<i>x</i></sub>Ti<sub><i>x</i></sub>O<sub>2</sub>) near the interface. These observations suggest that the thermal energy of the particles, influenced by laser fluence, is a critical factor in the formation of lattice strain in metal oxide films and also that laser fluence in PLD is an effective experimental parameter for strain management in oxide films. Our findings enhance the understanding of lattice strain formation in metal oxides and offer insights for establishing effective methods for controlling lattice strain in metal oxide films.</p>","PeriodicalId":50,"journal":{"name":"Langmuir","volume":null,"pages":null},"PeriodicalIF":3.7,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142589541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}