Pub Date : 2025-04-22DOI: 10.1021/acs.langmuir.5c00009
Gaoshuang Zuo, Hong Wang, Yanzhong Wang
Highly efficient and stable oxygen evolution reaction (OER) electrocatalysts are essential for electrochemical water splitting. Among non-noble metal-based catalysts, metal–organic frameworks (MOFs) have recently emerged as particularly promising candidates due to their exceptional surface areas, hierarchical porous structures, and tunable morphologies and compositions. The rational regulation of the morphology and electronic structure of pristine MOFs is considered a critical pathway for enhancing active sites and structural stability, thereby significantly boosting the OER catalytic performance. This review systematically presents the recent advancements in modulating pristine MOFs via heterogeneous metal doping, ligand substitution, and hybrid composite construction. With particular emphasis on synthetic methods, modification mechanisms, and the OER properties of MOFs, we analyze the fundamental relationships between structural modifications and electrocatalytic performance. Through the systematic analysis of existing research achievements, this review provides a holistic assessment of current state-of-the-art developments, identifies critical challenges, and proposes future research directions with practical implications for OER electrocatalyst design.
高效稳定的氧进化反应（OER）电催化剂对于电化学水分离至关重要。在以非贵金属为基础的催化剂中，金属有机框架（MOFs）因其特殊的比表面积、分层多孔结构、可调控的形态和组成，最近已成为特别有前途的候选催化剂。合理调节原始 MOF 的形态和电子结构被认为是增强活性位点和结构稳定性的关键途径，从而显著提高 OER 的催化性能。本综述系统地介绍了通过异质金属掺杂、配体置换和混合复合构建来调节原始 MOFs 的最新进展。我们特别强调了 MOFs 的合成方法、改性机制和 OER 特性，分析了结构改性与电催化性能之间的基本关系。通过对现有研究成果的系统分析，本综述全面评估了当前的最新发展，指出了关键挑战，并提出了对 OER 电催化剂设计具有实际意义的未来研究方向。
{"title":"Recent Progress of Modulating Pristine Metal–Organic Frameworks for Oxygen Reaction Revolution","authors":"Gaoshuang Zuo, Hong Wang, Yanzhong Wang","doi":"10.1021/acs.langmuir.5c00009","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00009","url":null,"abstract":"Highly efficient and stable oxygen evolution reaction (OER) electrocatalysts are essential for electrochemical water splitting. Among non-noble metal-based catalysts, metal–organic frameworks (MOFs) have recently emerged as particularly promising candidates due to their exceptional surface areas, hierarchical porous structures, and tunable morphologies and compositions. The rational regulation of the morphology and electronic structure of pristine MOFs is considered a critical pathway for enhancing active sites and structural stability, thereby significantly boosting the OER catalytic performance. This review systematically presents the recent advancements in modulating pristine MOFs via heterogeneous metal doping, ligand substitution, and hybrid composite construction. With particular emphasis on synthetic methods, modification mechanisms, and the OER properties of MOFs, we analyze the fundamental relationships between structural modifications and electrocatalytic performance. Through the systematic analysis of existing research achievements, this review provides a holistic assessment of current state-of-the-art developments, identifies critical challenges, and proposes future research directions with practical implications for OER electrocatalyst design.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"16 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858239","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00473
Renjith B. Nelliyil, Jaideep Mor, Amit Kaushal, Sandeep Kumar Sharma
The external stimuli-induced framework flexibility of zeolitic imidazolate frameworks (ZIFs) is a fascinating physical phenomenon. Flexible ZIFs offer varying pore aperture under gas pressures leading to inferior separation selectivity because the flexibility-induced enlargement in the aperture size allows diffusion of larger size gas molecules. Desolvated ZIF-7 crystals show high flexibility and phase transformation from the narrow pore (np) to the open pore (op) phase under CO2 pressure. Regulation of the gas-framework-induced flexibility of ZIF-7 is of paramount importance for enhancing its selectivity for gas separation and storage. Herein, we have exchanged the benzimidazole linker of ZIF-7 with varying amount (up to 62%) of 4,5-dichloroimidazole (dcIm), maintaining the sodalite topology and intracrystalline porosity. As a result of loading of the halogenated linker, the op phase of ZIF-7 can be obtained at room temperature in a desolvated form, which is otherwise exhibited only by the solvated ZIF-7. Using positron annihilation lifetime spectroscopy (PALS), it has been established that the pore architecture is significantly varied depending on the extent of linker mixing. The framework flexibility of ZIF-7 is determined by indexing the vacant volume available at the pore sites under the increasing CO2 pressure using in situ PALS. The flexibility of the mixed linker framework indexed through vacant volume evolution at pore sites under CO2 pressure is observed to be drastically reduced as compared to that of ZIF-7 due to the presence of the halogenated linker in the framework. The present study confirms that the pore architecture and flexibility of ZIF-7 can be efficiently regulated by incorporating varying amounts of dcIm in ZIF-7 frameworks.
{"title":"Regulation of CO2 Pressure-Induced Flexibility of Zeolitic Imidazolate Framework-7 Using a Mixed Linker Strategy: An In Situ Positron Annihilation Spectroscopy Study","authors":"Renjith B. Nelliyil, Jaideep Mor, Amit Kaushal, Sandeep Kumar Sharma","doi":"10.1021/acs.langmuir.5c00473","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00473","url":null,"abstract":"The external stimuli-induced framework flexibility of zeolitic imidazolate frameworks (ZIFs) is a fascinating physical phenomenon. Flexible ZIFs offer varying pore aperture under gas pressures leading to inferior separation selectivity because the flexibility-induced enlargement in the aperture size allows diffusion of larger size gas molecules. Desolvated ZIF-7 crystals show high flexibility and phase transformation from the narrow pore (<i>np</i>) to the open pore (<i>op</i>) phase under CO<sub>2</sub> pressure. Regulation of the gas-framework-induced flexibility of ZIF-7 is of paramount importance for enhancing its selectivity for gas separation and storage. Herein, we have exchanged the benzimidazole linker of ZIF-7 with varying amount (up to 62%) of 4,5-dichloroimidazole (dcIm), maintaining the sodalite topology and intracrystalline porosity. As a result of loading of the halogenated linker, the <i>op</i> phase of ZIF-7 can be obtained at room temperature in a desolvated form, which is otherwise exhibited only by the solvated ZIF-7. Using positron annihilation lifetime spectroscopy (PALS), it has been established that the pore architecture is significantly varied depending on the extent of linker mixing. The framework flexibility of ZIF-7 is determined by indexing the vacant volume available at the pore sites under the increasing CO<sub>2</sub> pressure using in situ PALS. The flexibility of the mixed linker framework indexed through vacant volume evolution at pore sites under CO<sub>2</sub> pressure is observed to be drastically reduced as compared to that of ZIF-7 due to the presence of the halogenated linker in the framework. The present study confirms that the pore architecture and flexibility of ZIF-7 can be efficiently regulated by incorporating varying amounts of dcIm in ZIF-7 frameworks.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"260 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858182","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00338
Ying Wu, Bei Shi, Lei Yang, Fei Wang, Lei Hou, Zhongguo Shan, Haihua Wang
Among the multitude of toxic water pollutants, Pb2+ poses a significant threat to human health. A novel magnetic manganese-based metal–organic framework (Mn-MOF) composite, MFCys, was designed for the selective removal of Pb2+. MFCys was readily synthesized through the postsynthetic modification of magnetic Mn-MOF/Fe3O4 (MF) with l-cysteine (l-Cys), utilizing a prospective Mn-MOF, {[Mn2(tzpa)(OH)(H2O)2]·DMA}n. MFCys demonstrated superior adsorption of Pb2+, reaching equilibrium within 2 h compared to Mn-MOF and MF. The Langmuir model indicated that MFCys underwent chemisorption of Pb2+. Meanwhile, the adsorption process aligned with the pseudo-second-order (PSO) kinetic model, confirming that Pb2+ was adsorbed by MFCys mainly through monolayer chemisorption. Thermodynamic results revealed that the adsorption of Pb2+ by MFCys was spontaneous and endothermic. Moreover, even in the presence of competing Cd2+, Zn2+, Ca2+, Mg2+, Na+, K+, and Pb2+, MFCys exhibited exceptional selectivity for Pb2+ due to the electrostatic interaction and the electronic coupling effect between MFCys and Pb2+. The magnetic MFCys enabled easy separation from the suspension within 1 min by using an external magnet for recycling. MFCys retained 98.0% of the initial adsorption capacity for Pb2+ after five cycles, demonstrating excellent reusability. Notably, MFCys displayed exceptional adsorption of Pb2+ in simulated lead-acid battery wastewater, retaining 98.3% of its pristine adsorption capacity for Pb2+ even after five cycles. These findings suggest that an easily separated Mn-MOF composite has promising application prospects in Pb2+ wastewater treatment.
{"title":"Cysteine-Functionalized Magnetic Manganese-Based MOF Composite for Enhanced Removal of Pb2+ from Water","authors":"Ying Wu, Bei Shi, Lei Yang, Fei Wang, Lei Hou, Zhongguo Shan, Haihua Wang","doi":"10.1021/acs.langmuir.5c00338","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00338","url":null,"abstract":"Among the multitude of toxic water pollutants, Pb<sup>2+</sup> poses a significant threat to human health. A novel magnetic manganese-based metal–organic framework (Mn-MOF) composite, MFCys, was designed for the selective removal of Pb<sup>2+</sup>. MFCys was readily synthesized through the postsynthetic modification of magnetic Mn-MOF/Fe<sub>3</sub>O<sub>4</sub> (MF) with <span>l</span>-cysteine (<span>l</span>-Cys), utilizing a prospective Mn-MOF, {[Mn<sub>2</sub>(tzpa)(OH)(H<sub>2</sub>O)<sub>2</sub>]·DMA}<i><sub>n</sub></i>. MFCys demonstrated superior adsorption of Pb<sup>2+</sup>, reaching equilibrium within 2 h compared to Mn-MOF and MF. The Langmuir model indicated that MFCys underwent chemisorption of Pb<sup>2+</sup>. Meanwhile, the adsorption process aligned with the pseudo-second-order (PSO) kinetic model, confirming that Pb<sup>2+</sup> was adsorbed by MFCys mainly through monolayer chemisorption. Thermodynamic results revealed that the adsorption of Pb<sup>2+</sup> by MFCys was spontaneous and endothermic. Moreover, even in the presence of competing Cd<sup>2+</sup>, Zn<sup>2+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup>, K<sup>+</sup>, and Pb<sup>2+</sup>, MFCys exhibited exceptional selectivity for Pb<sup>2+</sup> due to the electrostatic interaction and the electronic coupling effect between MFCys and Pb<sup>2+</sup>. The magnetic MFCys enabled easy separation from the suspension within 1 min by using an external magnet for recycling. MFCys retained 98.0% of the initial adsorption capacity for Pb<sup>2+</sup> after five cycles, demonstrating excellent reusability. Notably, MFCys displayed exceptional adsorption of Pb<sup>2+</sup> in simulated lead-acid battery wastewater, retaining 98.3% of its pristine adsorption capacity for Pb<sup>2+</sup> even after five cycles. These findings suggest that an easily separated Mn-MOF composite has promising application prospects in Pb<sup>2+</sup> wastewater treatment.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"38 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858242","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00936
Mingzhu Cui, Anthony D. Dinsmore
Droplets that partially wet solid surfaces exhibit hysteresis in their contact angle. The values of the minimum (receding) and maximum (advancing) angles, θR and θA, are empirically well-defined and thought to be unique for a given set of materials. We measured the contact angles of water droplets hanging from hydrophobic, PDMS-functionalized glass and found that the value of θR varies with the curvature of the glass. The effect is substantial: θR changes from 86.0 ± 1.9° on a flat plate to 95.6 ± 1.9° on a 2 mm diameter rod of the same material. The measured values of θA were independent of geometry (θA = 103.2 ± 0.9°). We found a consistent trend among PDMS-functionalized glass cylinders with diameters ranging from 2 to 12.7 mm. We also measured the speed at which the contact line moved just after receding; these results showed a receding speed ∝ cos(θR) – cos(θE) and a consistent equilibrium contact angle, θE = 103.4 ± 2.3°. Finally, we measured the sliding of water droplets as rods were tilted. The larger θR (and thus smaller hysteresis) for a 2 mm-diameter rod led to droplets sliding at a tilt angle of just 21° from horizontal, compared to the 48° minimum tilt for a 7 mm rod. The results show that hysteresis arises from an energy barrier that depends on the shape of the droplet and contact line, both of which change with substrate curvature. The results may lead to designing surfaces that better trap water droplets or shed them for self-cleaning or water-harvesting applications.
{"title":"Geometry Dependence of the Receding Angle of a Droplet on a Solid Cylindrical Surface","authors":"Mingzhu Cui, Anthony D. Dinsmore","doi":"10.1021/acs.langmuir.5c00936","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00936","url":null,"abstract":"Droplets that partially wet solid surfaces exhibit hysteresis in their contact angle. The values of the minimum (receding) and maximum (advancing) angles, θ<sub>R</sub> and θ<sub>A</sub>, are empirically well-defined and thought to be unique for a given set of materials. We measured the contact angles of water droplets hanging from hydrophobic, PDMS-functionalized glass and found that the value of θ<sub>R</sub> varies with the curvature of the glass. The effect is substantial: θ<sub>R</sub> changes from 86.0 ± 1.9° on a flat plate to 95.6 ± 1.9° on a 2 mm diameter rod of the same material. The measured values of θ<sub>A</sub> were independent of geometry (θ<sub>A</sub> = 103.2 ± 0.9°). We found a consistent trend among PDMS-functionalized glass cylinders with diameters ranging from 2 to 12.7 mm. We also measured the speed at which the contact line moved just after receding; these results showed a receding speed ∝ cos(θ<sub>R</sub>) – cos(θ<sub>E</sub>) and a consistent equilibrium contact angle, θ<sub>E</sub> = 103.4 ± 2.3°. Finally, we measured the sliding of water droplets as rods were tilted. The larger θ<sub>R</sub> (and thus smaller hysteresis) for a 2 mm-diameter rod led to droplets sliding at a tilt angle of just 21° from horizontal, compared to the 48° minimum tilt for a 7 mm rod. The results show that hysteresis arises from an energy barrier that depends on the shape of the droplet and contact line, both of which change with substrate curvature. The results may lead to designing surfaces that better trap water droplets or shed them for self-cleaning or water-harvesting applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"52 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853427","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00595
Jian Wang, Haitao Hei, Hongfei Ye, Yonggang Zheng, Hongwu Zhang
Heterogeneous confinement systems attract increasing attention owing to their widespread applications in diverse areas. However, it is still lacking an in-depth understanding of the diffusion mechanism and physical properties of water in the heterogeneous nanochannel through molecular simulations. Here, high-precision TIP4P-BGWT water molecules confined in molybdenum disulfide (MoS2) and graphene walls are utilized to investigate the influences of variables, i.e., channel height, wettability of walls, charge of MoS2, and temperature, on the diffusion mechanism and physical properties. The simulation results indicate that the diffusion mechanism is significantly affected by the channel height and temperature but weakly influenced by the wettability of walls. Observable impacts on the physical properties can be observed with the channel height and temperature, but slight impacts are observed with the wettability of walls. Considered variables, excluding charge of MoS2, remarkably influence density distribution, while limiting mean square displacement at the channel height depends solely upon the effective diffusion distance. It is worth noting that, compared to the homostructure, significant discrepancy in the density distribution can be obtained from the heterogeneous nanochannel due to different solid–liquid interactions. The present study offers a solid foundation for the design of nanodevices, such as nanomembrane, nanosensor, microfluidic chip, etc.
{"title":"Untangling the Diffusion Mechanism of Water in a Heterogeneous Nanochannel","authors":"Jian Wang, Haitao Hei, Hongfei Ye, Yonggang Zheng, Hongwu Zhang","doi":"10.1021/acs.langmuir.5c00595","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00595","url":null,"abstract":"Heterogeneous confinement systems attract increasing attention owing to their widespread applications in diverse areas. However, it is still lacking an in-depth understanding of the diffusion mechanism and physical properties of water in the heterogeneous nanochannel through molecular simulations. Here, high-precision TIP4P-BGWT water molecules confined in molybdenum disulfide (MoS<sub>2</sub>) and graphene walls are utilized to investigate the influences of variables, i.e., channel height, wettability of walls, charge of MoS<sub>2</sub>, and temperature, on the diffusion mechanism and physical properties. The simulation results indicate that the diffusion mechanism is significantly affected by the channel height and temperature but weakly influenced by the wettability of walls. Observable impacts on the physical properties can be observed with the channel height and temperature, but slight impacts are observed with the wettability of walls. Considered variables, excluding charge of MoS<sub>2</sub>, remarkably influence density distribution, while limiting mean square displacement at the channel height depends solely upon the effective diffusion distance. It is worth noting that, compared to the homostructure, significant discrepancy in the density distribution can be obtained from the heterogeneous nanochannel due to different solid–liquid interactions. The present study offers a solid foundation for the design of nanodevices, such as nanomembrane, nanosensor, microfluidic chip, etc.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"32 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858243","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00378
Ahamed Milton, Abdullah Al Mahmud, Ramaraj Sukanya, Raj Karthik, Eswaran Kamaraj, Carmel B. Breslin, P. Muhammed Shafi, Jae-Jin Shim
The development of hierarchical core–shell structures and multicomponent metal boride/metal oxide-based composites presents a promising strategy to enhance supercapacitor (SC) performance. In this study, we synthesized a Ni3B@Ni(BO2)2 (0D@2D) core–shell structure and integrated it with V2MoO8 (VMO) rods (1D) to form a Ni3B@Ni(BO2)2/VMO (NB@NBO/VMO (0D@2D/1D)) composite. This composite was then used as an electrode material on a flexible carbon cloth (CC) substrate for SC applications. The 1D-VMO rods were derived from V-doped MoSe2 nanosheets via hydrothermal synthesis and calcination, while the NB@NBO/VMO composite was obtained by using a liquid-phase method. Structural, compositional, and morphological characterizations were conducted using XRD, XPS, FE-SEM, and TEM-EDS. In a three-electrode system, the NB@NBO/VMO-50 composite showed an impressive Cs of 698 F g–1 at 1 A g–1, ascribed to its unique core–shell architecture, which enhances contact and faradaic properties, shortens ion diffusion paths, and provides abundant active sites. Notably, the NB@NBO/VMO-50 displayed excellent cyclic stability, retaining 75.1% of its capacitance after 10,000 cycles at 10 A g–1. This performance is better than those of other electrodes, including pristine VMO/CC, NB/CC, NB@NBO/VMO-25, and NB@NBO/VMO-75. When evaluated in a two-electrode asymmetric SC system, the NB@NBO/VMO-50/CC||rGO device operated at 1.6 V and delivered a high energy density (ED) of 40.5 Wh kg–1 at a power density (PD) of 800 W kg–1. It also reached a PD of 16,000 W kg–1 while maintaining an ED of 23.5 Wh kg–1. The device also showed remarkable long-term durability, maintaining 79.3% of its capacitance and 99.9% Coulombic efficiency after 8000 charge–discharge cycles at 8 A g–1, demonstrating its strong potential for next-generation energy storage applications.
{"title":"Structural Engineering of Core–Shell Ni3B@Ni(BO2)2 on V2MoO8 (0D@2D/1D) Composites: Advanced Strategies for Enhancing High Energy Density in Asymmetric Supercapacitors","authors":"Ahamed Milton, Abdullah Al Mahmud, Ramaraj Sukanya, Raj Karthik, Eswaran Kamaraj, Carmel B. Breslin, P. Muhammed Shafi, Jae-Jin Shim","doi":"10.1021/acs.langmuir.5c00378","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00378","url":null,"abstract":"The development of hierarchical core–shell structures and multicomponent metal boride/metal oxide-based composites presents a promising strategy to enhance supercapacitor (SC) performance. In this study, we synthesized a Ni<sub>3</sub>B@Ni(BO<sub>2</sub>)<sub>2</sub> (0D@2D) core–shell structure and integrated it with V<sub>2</sub>MoO<sub>8</sub> (VMO) rods (1D) to form a Ni<sub>3</sub>B@Ni(BO<sub>2</sub>)<sub>2</sub>/VMO (NB@NBO/VMO (0D@2D/1D)) composite. This composite was then used as an electrode material on a flexible carbon cloth (CC) substrate for SC applications. The 1D-VMO rods were derived from V-doped MoSe<sub>2</sub> nanosheets via hydrothermal synthesis and calcination, while the NB@NBO/VMO composite was obtained by using a liquid-phase method. Structural, compositional, and morphological characterizations were conducted using XRD, XPS, FE-SEM, and TEM-EDS. In a three-electrode system, the NB@NBO/VMO-50 composite showed an impressive <i>C</i><sub>s</sub> of 698 F g<sup>–1</sup> at 1 A g<sup>–1</sup>, ascribed to its unique core–shell architecture, which enhances contact and faradaic properties, shortens ion diffusion paths, and provides abundant active sites. Notably, the NB@NBO/VMO-50 displayed excellent cyclic stability, retaining 75.1% of its capacitance after 10,000 cycles at 10 A g<sup>–1</sup>. This performance is better than those of other electrodes, including pristine VMO/CC, NB/CC, NB@NBO/VMO-25, and NB@NBO/VMO-75. When evaluated in a two-electrode asymmetric SC system, the NB@NBO/VMO-50/CC||rGO device operated at 1.6 V and delivered a high energy density (ED) of 40.5 Wh kg<sup>–1</sup> at a power density (PD) of 800 W kg<sup>–1</sup>. It also reached a PD of 16,000 W kg<sup>–1</sup> while maintaining an ED of 23.5 Wh kg<sup>–1</sup>. The device also showed remarkable long-term durability, maintaining 79.3% of its capacitance and 99.9% Coulombic efficiency after 8000 charge–discharge cycles at 8 A g<sup>–1</sup>, demonstrating its strong potential for next-generation energy storage applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"33 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853426","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 : 2025-04-21DOI: 10.1021/acs.langmuir.4c04778
Emily A. Beeman, Zhimin Jiang, Jamie Ford, James H. Pikul
Self-assembled materials, studied for optical, mechanical, and fluidic applications, have not yet been widely adopted due to slow manufacturing times. We demonstrate a drop-casting process that provides a rapid approach to fabricate large and thick opals from 40 to 55% w/v solutions of charged polystyrene particles. The high concentration allows for rapid drying, leading to fast assembly times, and the charged particles repel in solution and partially order prior to evaporation. Cryo-FIB SEM images of frozen solutions combined with inverse opals fabricated from still-wet templates visualize the particle ordering prior to assembly. This method produces well-ordered opals with areas of 6.25–100 cm2 and thickness of 100–150 μm, which take 0.5–1.25 h to assemble. In addition, the procedure enables continuous fabrication using a doctor blade to spread the material across the substrate. We demonstrate feasible and scalable opal and inverse opal fabrication.
{"title":"Scalable Fabrication of Thick Opals through Drop-Casting Concentrated Suspensions with In-Solution Ordering","authors":"Emily A. Beeman, Zhimin Jiang, Jamie Ford, James H. Pikul","doi":"10.1021/acs.langmuir.4c04778","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c04778","url":null,"abstract":"Self-assembled materials, studied for optical, mechanical, and fluidic applications, have not yet been widely adopted due to slow manufacturing times. We demonstrate a drop-casting process that provides a rapid approach to fabricate large and thick opals from 40 to 55% w/v solutions of charged polystyrene particles. The high concentration allows for rapid drying, leading to fast assembly times, and the charged particles repel in solution and partially order prior to evaporation. Cryo-FIB SEM images of frozen solutions combined with inverse opals fabricated from still-wet templates visualize the particle ordering prior to assembly. This method produces well-ordered opals with areas of 6.25–100 cm<sup>2</sup> and thickness of 100–150 μm, which take 0.5–1.25 h to assemble. In addition, the procedure enables continuous fabrication using a doctor blade to spread the material across the substrate. We demonstrate feasible and scalable opal and inverse opal fabrication.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"108 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858240","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00074
Jingshuo Zhang, Xiaoming Ni, Gaofeng Liu, Xiao Liu
The fracturing fluid with an added surfactant is conducive to backflow, and it is gaining more and more popularity in coal seam hydraulic fracturing projects. At the same time, the types and concentrations of mineral ions in the solution have an important impact on the backflow of the fracturing fluid. With K+ and Cl– as representative ions of the mineralization degree of water solutions, understanding the mechanism of K+ and Cl– on the wettability of surfactant-modified coal can provide a scientific theoretical basis for the backflow of the fracturing fluid. Based on this issue, Shanxi Changping Coal Mine coal samples were selected, and simulation methods were used to study the intervention effect of KCl on the wettability behavior of different types of surfactant-modified coal. The wettability behavior mechanism of KCl on different types of surfactant-modified coal was revealed through parameters such as radial distribution function (RDF), hydrogen bonds, diffusion behavior (mean square displacement), and interaction energy. Results show that under intervention using KCl, the peaks in RDFs of surfactants and water decrease significantly; the number of hydrogen bonds decreases by 22.02–40.48%; and the binding energy decreases by 41.32%–58.23%. The occurrence of nonionic surfactant APG in the aqueous solution changes it from a dispersed into an agglomerated distribution, while that of ionic surfactants exhibits the opposite trend. The diffusion coefficient of water in surfactant solutions decreases by more than 59.56%. Under intervention using KCl, the wettabilities of coal modified by different surfactants all decline. After intervention using KCl, the electrostatic force decreases sharply in the interaction energy between coal modified by the three surfactants APG, SDBS, and BS-12 and water, while the van der Waals (VDW) force is only slightly affected; the VDW force increases in the interaction energy between CTAB-modified coal and water.
{"title":"Wetting Behaviors and Mechanisms of Coal Modified by Different Types of Surfactants under Intervention Using KCl","authors":"Jingshuo Zhang, Xiaoming Ni, Gaofeng Liu, Xiao Liu","doi":"10.1021/acs.langmuir.5c00074","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00074","url":null,"abstract":"The fracturing fluid with an added surfactant is conducive to backflow, and it is gaining more and more popularity in coal seam hydraulic fracturing projects. At the same time, the types and concentrations of mineral ions in the solution have an important impact on the backflow of the fracturing fluid. With K<sup>+</sup> and Cl<sup>–</sup> as representative ions of the mineralization degree of water solutions, understanding the mechanism of K<sup>+</sup> and Cl<sup>–</sup> on the wettability of surfactant-modified coal can provide a scientific theoretical basis for the backflow of the fracturing fluid. Based on this issue, Shanxi Changping Coal Mine coal samples were selected, and simulation methods were used to study the intervention effect of KCl on the wettability behavior of different types of surfactant-modified coal. The wettability behavior mechanism of KCl on different types of surfactant-modified coal was revealed through parameters such as radial distribution function (RDF), hydrogen bonds, diffusion behavior (mean square displacement), and interaction energy. Results show that under intervention using KCl, the peaks in RDFs of surfactants and water decrease significantly; the number of hydrogen bonds decreases by 22.02–40.48%; and the binding energy decreases by 41.32%–58.23%. The occurrence of nonionic surfactant APG in the aqueous solution changes it from a dispersed into an agglomerated distribution, while that of ionic surfactants exhibits the opposite trend. The diffusion coefficient of water in surfactant solutions decreases by more than 59.56%. Under intervention using KCl, the wettabilities of coal modified by different surfactants all decline. After intervention using KCl, the electrostatic force decreases sharply in the interaction energy between coal modified by the three surfactants APG, SDBS, and BS-12 and water, while the van der Waals (VDW) force is only slightly affected; the VDW force increases in the interaction energy between CTAB-modified coal and water.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"56 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853389","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 : 2025-04-21DOI: 10.1021/acs.langmuir.5c00087
Dingcen Duan, Sen Ren, Yatian Huang, Zhanglong Tang, Yan Wang, Xin Chen, Xingbo Ge
In this study, a self-supported material with a unique ternary metal sulfide nanorod array structure was fabricated in situ on copper foam via a facile one-step electrodeposition approach ((NiCo–Cu)Sx/CF). The electrochemically driven rapid generation of abundant S2– ions from thiourea accelerates their combination with Ni2+ and Co2+, resulting in a catalytically enriched surface on the nanorod array. The high-density nanorod arrays provide maximally accessible active sites, thereby enhancing the hydrogen evolution reaction (HER). The in situ grown self-supported structure effectively eliminates the need for binders (common in conventional catalysts), avoids additional interfacial resistance, and ensures long-term stability during electrocatalytic operation. The synergistic interactions among the metal components (Ni, Co, and Cu) optimize the local electronic environment, creating favorable conditions for catalytic hydrogen evolution. The experimental results demonstrate that the ternary metal sulfide nanocomposite (denoted as (NiCo–Cu)Sx/CF) exhibits superior hydrogen evolution reaction performance compared to its binary counterparts. Remarkably, the catalyst required only 42 and 161 mV overpotential to deliver 10 mA·cm–2 and 100 mA·cm–2 current densities in 1 M KOH, respectively, with 100 h operational stability. This work provides a viable strategy for developing self-supported ternary non-noble metal catalysts for energy conversion applications.
{"title":"One-Step Electrodeposition of Ternary Metal Sulfide Composite Nanorod Arrays as a Self-Supported Electrocatalyst for the Hydrogen Evolution Reaction","authors":"Dingcen Duan, Sen Ren, Yatian Huang, Zhanglong Tang, Yan Wang, Xin Chen, Xingbo Ge","doi":"10.1021/acs.langmuir.5c00087","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00087","url":null,"abstract":"In this study, a self-supported material with a unique ternary metal sulfide nanorod array structure was fabricated in situ on copper foam via a facile one-step electrodeposition approach ((NiCo–Cu)S<sub><i>x</i></sub>/CF). The electrochemically driven rapid generation of abundant S<sup>2–</sup> ions from thiourea accelerates their combination with Ni<sup>2+</sup> and Co<sup>2+</sup>, resulting in a catalytically enriched surface on the nanorod array. The high-density nanorod arrays provide maximally accessible active sites, thereby enhancing the hydrogen evolution reaction (HER). The in situ grown self-supported structure effectively eliminates the need for binders (common in conventional catalysts), avoids additional interfacial resistance, and ensures long-term stability during electrocatalytic operation. The synergistic interactions among the metal components (Ni, Co, and Cu) optimize the local electronic environment, creating favorable conditions for catalytic hydrogen evolution. The experimental results demonstrate that the ternary metal sulfide nanocomposite (denoted as (NiCo–Cu)S<sub><i>x</i></sub>/CF) exhibits superior hydrogen evolution reaction performance compared to its binary counterparts. Remarkably, the catalyst required only 42 and 161 mV overpotential to deliver 10 mA·cm<sup>–2</sup> and 100 mA·cm<sup>–2</sup> current densities in 1 M KOH, respectively, with 100 h operational stability. This work provides a viable strategy for developing self-supported ternary non-noble metal catalysts for energy conversion applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"6 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143858241","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 : 2025-04-20DOI: 10.1021/acs.langmuir.4c05381
Rosangela Mastrangelo, Teresa Guaragnone, Andrea Casini, Damiano Bandelli, David Chelazzi, Piero Baglioni
The remedial conservation of cultural heritage requires advanced functional materials that span from soft matter to nanostructured formulations, whose study is relevant to different fields, ranging from cosmetics and detergency to tissue engineering. In the vast landscape of innovative materials developed to counteract artwork degradation, gels have emerged as ideal candidates for cleaning delicate and complex surfaces. More specifically, twin-chain networks (TCNs), i.e., sponge-like hydrogels obtained through spontaneous polymer–polymer phase separation and sustainable freeze–thawing, showed unprecedented cleaning performances on modern/contemporary iconic paintings, such as works by Jackson Pollock and Pablo Picasso. The key to their efficacy lies in the complex cleaning mechanism at the gel–substrate interface. Recent findings suggest that the pore size and connectivity, affecting the nanoscale tortuosity, play a crucial role in determining the gels’ uptake (cleaning) ability. Nonetheless, diffusion of soil through the gel networks is only part of the complex processes that control the removal of unwanted layers from painted surfaces. A deeper understanding of the cleaning mechanism requires studying the uptake of solid particulate matter: gel adhesion and surface roughness affect the cleaning performance of a gel. In this work, TCNs with modulated porosity, obtained by mixing poly(vinyl alcohol)s (PVAs) of different hydrolysis degrees and molecular weights, were characterized through different techniques (confocal laser scanning microscopy, scanning electron microscopy, differential scanning calorimetry, and rheology) to relate porosity and structural features to the surface roughness and diffusional properties of the gels. Finally, cleaning tests on model painted surfaces revealed a clear connection between the surface inhomogeneity and the cleaning performance of the gels.
{"title":"“Twin-Chain” Hydrogels with Tailored Porosity, Surface Roughness, and Cleaning Capabilities","authors":"Rosangela Mastrangelo, Teresa Guaragnone, Andrea Casini, Damiano Bandelli, David Chelazzi, Piero Baglioni","doi":"10.1021/acs.langmuir.4c05381","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05381","url":null,"abstract":"The remedial conservation of cultural heritage requires advanced functional materials that span from soft matter to nanostructured formulations, whose study is relevant to different fields, ranging from cosmetics and detergency to tissue engineering. In the vast landscape of innovative materials developed to counteract artwork degradation, gels have emerged as ideal candidates for cleaning delicate and complex surfaces. More specifically, twin-chain networks (TCNs), i.e., sponge-like hydrogels obtained through spontaneous polymer–polymer phase separation and sustainable freeze–thawing, showed unprecedented cleaning performances on modern/contemporary iconic paintings, such as works by Jackson Pollock and Pablo Picasso. The key to their efficacy lies in the complex cleaning mechanism at the gel–substrate interface. Recent findings suggest that the pore size and connectivity, affecting the nanoscale tortuosity, play a crucial role in determining the gels’ uptake (cleaning) ability. Nonetheless, diffusion of soil through the gel networks is only part of the complex processes that control the removal of unwanted layers from painted surfaces. A deeper understanding of the cleaning mechanism requires studying the uptake of solid particulate matter: gel adhesion and surface roughness affect the cleaning performance of a gel. In this work, TCNs with modulated porosity, obtained by mixing poly(vinyl alcohol)s (PVAs) of different hydrolysis degrees and molecular weights, were characterized through different techniques (confocal laser scanning microscopy, scanning electron microscopy, differential scanning calorimetry, and rheology) to relate porosity and structural features to the surface roughness and diffusional properties of the gels. Finally, cleaning tests on model painted surfaces revealed a clear connection between the surface inhomogeneity and the cleaning performance of the gels.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"108 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853430","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}
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