Monodisperse SiO2 microspheres are widely used in catalysis, separation, adsorption, and drug delivery. Their particle size, uniformity, and specific surface area are crucial for these applications. This study reports the novel preparation of monodisperse SiO2 microspheres using cetyltrimethylammonium bromide as the template agent, employing hexadecylamine serving concurrently as a pore-expanding agent and catalyst. By controlling the reactant quantities and reaction conditions, we achieved monodisperse SiO2 microspheres with tunable particle sizes ranging from 800 nm to 2.5 μm with exceptionally large specific surface areas. It is worth mentioning that microspheres with a particle size of 2 μm and extremely uniform size distribution were produced at room temperature. Excitingly, it has a BET specific surface area of 1543 m2/g. Various effects on the preparation of the microspheres were investigated in detail, and the growth mechanism of these microspheres was elucidated.
{"title":"Monodisperse Silica Microsphere with Extremely Large Specific Surface Area: Preparation and Characterization","authors":"Ruicheng Xiao, Siming Yu, Zhongsheng Tang, Jianping Tang, Hang Zhang, Shengliang Zhong","doi":"10.1021/acs.langmuir.5c00607","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00607","url":null,"abstract":"Monodisperse SiO<sub>2</sub> microspheres are widely used in catalysis, separation, adsorption, and drug delivery. Their particle size, uniformity, and specific surface area are crucial for these applications. This study reports the novel preparation of monodisperse SiO<sub>2</sub> microspheres using cetyltrimethylammonium bromide as the template agent, employing hexadecylamine serving concurrently as a pore-expanding agent and catalyst. By controlling the reactant quantities and reaction conditions, we achieved monodisperse SiO<sub>2</sub> microspheres with tunable particle sizes ranging from 800 nm to 2.5 μm with exceptionally large specific surface areas. It is worth mentioning that microspheres with a particle size of 2 μm and extremely uniform size distribution were produced at room temperature. Excitingly, it has a BET specific surface area of 1543 m<sup>2</sup>/g. Various effects on the preparation of the microspheres were investigated in detail, and the growth mechanism of these microspheres was elucidated.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143872637","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 : 2025-04-25DOI: 10.1021/acs.langmuir.5c00629
Jia Ming Goh, Ali Zavabeti, Jianan He, Shuangmin Shi, Amanda Vera Ellis, Gang Kevin Li
Micro- or nanoscale gas vessels decentralize gas storage, enabling high-density gas storage at ambient pressure. However, current materials are constrained by complex designs and the need for intensive production and operational conditions. Here, we demonstrate the use of frozen water (ice) to encapsulate commonly available activated carbon (AC), forming microscale vessels where high-density gas is stored within carbon nanopores. Hydrophilic functional groups on the AC surface create water competition for adsorption sites within the pores, reducing the capacity available for gas molecules. This effect diminishes with increasing gas dosage pressure. At 50 bar, methane (CH4) dosage, stored at ambient pressure and −20 °C, shows that approximately 90% of the deliverable capacity was retained using this water-assisted method─an amount 320% higher than that achieved with traditional adsorption methods under identical conditions. For low-polarizable gases like nitrogen (N2) and hydrogen (H2), competitive adsorption significantly reduced performance; however, heat treatment of AC at 1000 °C in argon (Ar) effectively reduced oxygenated functional groups, resulting in a 32 and 48% increase in deliverable N2 and H2 capacities, respectively. This study presents a cost-effective, sustainable approach to gas storage using widely available materials and simple operation, advancing the potential for CH4 and H2 storage in clean energy systems.
{"title":"Porous Carbon-Ice Composite Microscale Vessels for Gas Encapsulation and Storage","authors":"Jia Ming Goh, Ali Zavabeti, Jianan He, Shuangmin Shi, Amanda Vera Ellis, Gang Kevin Li","doi":"10.1021/acs.langmuir.5c00629","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00629","url":null,"abstract":"Micro- or nanoscale gas vessels decentralize gas storage, enabling high-density gas storage at ambient pressure. However, current materials are constrained by complex designs and the need for intensive production and operational conditions. Here, we demonstrate the use of frozen water (ice) to encapsulate commonly available activated carbon (AC), forming microscale vessels where high-density gas is stored within carbon nanopores. Hydrophilic functional groups on the AC surface create water competition for adsorption sites within the pores, reducing the capacity available for gas molecules. This effect diminishes with increasing gas dosage pressure. At 50 bar, methane (CH<sub>4</sub>) dosage, stored at ambient pressure and −20 °C, shows that approximately 90% of the deliverable capacity was retained using this water-assisted method─an amount 320% higher than that achieved with traditional adsorption methods under identical conditions. For low-polarizable gases like nitrogen (N<sub>2</sub>) and hydrogen (H<sub>2</sub>), competitive adsorption significantly reduced performance; however, heat treatment of AC at 1000 °C in argon (Ar) effectively reduced oxygenated functional groups, resulting in a 32 and 48% increase in deliverable N<sub>2</sub> and H<sub>2</sub> capacities, respectively. This study presents a cost-effective, sustainable approach to gas storage using widely available materials and simple operation, advancing the potential for CH<sub>4</sub> and H<sub>2</sub> storage in clean energy systems.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"2 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143872638","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}
This study aims to address the increasingly complex environmental demands by enhancing the high-temperature durability of asphalt pavements during service, study on the effect and mechanism of silicon carbide (SiC) ceramic micropowder on the performance of modified asphalt. The rheological properties and modification mechanism of SiC-modified asphalt were analyzed using Saturates, Aromatics, Resins, and Asphaltenes (SARA) fraction analysis, viscosity tests, dynamic shear rheological (DSR) tests, Fourier transform infrared spectroscopy (FTIR), and molecular dynamics (MD) simulations. The results show that SiC ceramic micropowder, with its high specific surface area and rich porous structure, effectively adsorbs the lighter components of asphalt, significantly improving its viscosity and high-temperature stability. Rheological tests demonstrate that SiC ceramic micropowder significantly increases the viscosity and rutting factor of asphalt, with a 34.74% improvement in G*/sin δ at 60 °C, indicating a marked enhancement in high-temperature performance. FTIR spectra confirm that the modification of asphalt by SiC is a physical process, as no new functional groups were formed. MD simulations reveal that the interfacial energy between SiC and asphalt is negative, indicating an attractive interaction between the two phases. The selective adsorption of SiC on the SARA fractions follows the order: aromatics > resins > saturates > asphaltenes, which promotes the aggregation of saturates and aromatics on the SiC surface, altering the composition of asphalt. In conclusion, the interfacial interactions and selective adsorption characteristics of SiC ceramic micropowder significantly enhance the viscosity and high-temperature performance of asphalt. This study provides a theoretical foundation for the practical application of SiC ceramic micropowder in high-temperature asphalt environments and offers valuable insights for its engineering applications.
{"title":"High-Temperature Rheological and Molecular Dynamics Analysis of Asphalt Modified with SiC Filler","authors":"Meijun Song, Ying Gao, Guangyao Li, Xiaobo Lv, Yajun Zhao, Xiaoxiong Zhang, Hui Luo","doi":"10.1021/acs.langmuir.4c05075","DOIUrl":"https://doi.org/10.1021/acs.langmuir.4c05075","url":null,"abstract":"This study aims to address the increasingly complex environmental demands by enhancing the high-temperature durability of asphalt pavements during service, study on the effect and mechanism of silicon carbide (SiC) ceramic micropowder on the performance of modified asphalt. The rheological properties and modification mechanism of SiC-modified asphalt were analyzed using Saturates, Aromatics, Resins, and Asphaltenes (SARA) fraction analysis, viscosity tests, dynamic shear rheological (DSR) tests, Fourier transform infrared spectroscopy (FTIR), and molecular dynamics (MD) simulations. The results show that SiC ceramic micropowder, with its high specific surface area and rich porous structure, effectively adsorbs the lighter components of asphalt, significantly improving its viscosity and high-temperature stability. Rheological tests demonstrate that SiC ceramic micropowder significantly increases the viscosity and rutting factor of asphalt, with a 34.74% improvement in G*/sin δ at 60 °C, indicating a marked enhancement in high-temperature performance. FTIR spectra confirm that the modification of asphalt by SiC is a physical process, as no new functional groups were formed. MD simulations reveal that the interfacial energy between SiC and asphalt is negative, indicating an attractive interaction between the two phases. The selective adsorption of SiC on the SARA fractions follows the order: aromatics > resins > saturates > asphaltenes, which promotes the aggregation of saturates and aromatics on the SiC surface, altering the composition of asphalt. In conclusion, the interfacial interactions and selective adsorption characteristics of SiC ceramic micropowder significantly enhance the viscosity and high-temperature performance of asphalt. This study provides a theoretical foundation for the practical application of SiC ceramic micropowder in high-temperature asphalt environments and offers valuable insights for its engineering applications.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"14 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143872635","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 : 2025-04-25DOI: 10.1021/acs.langmuir.5c00138
Babalola Aisosa Oni
Green H2 production via electrochemical water splitting has emerged as a pivotal solution for achieving a sustainable energy future. This Review delves into the fundamentals of water splitting, focusing on the O2 evolution reaction (OER) and H2 evolution reaction (HER), and focuses on the critical role of electrocatalysts in these processes. Precious metals such as paltinum and iridium remain the benchmarks for catalytic performance; however, their scarcity and high cost necessitate the development of alternative materials. Recent advances in Earth-abundant catalysts, including transition-metal oxides, carbides, nitrides, and sulfides, have shown promise in balancing activity, durability, and affordability. The integration of nanostructuring techniques and computational modeling has enabled the design of catalysts with enhanced active site exposure and electronic properties. Furthermore, the Review highlights challenges such as material degradation, high overpotentials, and gas crossover, along with potential solutions like protective coatings, bifunctional catalysts, and advanced electrolyzer designs. Future prospects emphasize the role of artificial intelligence, hybrid systems, and sustainable manufacturing in accelerating progress. This comprehensive review underscores the significance of bridging fundamental research with technological innovations to scale up green hydrogen production, addressing energy demands while mitigating environmental impacts.
{"title":"A Review on Electrochemical Water Splitting Electrocatalysts for Green H2 Production: Unveiling the Fundamentals and Recent Advances","authors":"Babalola Aisosa Oni","doi":"10.1021/acs.langmuir.5c00138","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00138","url":null,"abstract":"Green H<sub>2</sub> production via electrochemical water splitting has emerged as a pivotal solution for achieving a sustainable energy future. This Review delves into the fundamentals of water splitting, focusing on the O<sub>2</sub> evolution reaction (OER) and H<sub>2</sub> evolution reaction (HER), and focuses on the critical role of electrocatalysts in these processes. Precious metals such as paltinum and iridium remain the benchmarks for catalytic performance; however, their scarcity and high cost necessitate the development of alternative materials. Recent advances in Earth-abundant catalysts, including transition-metal oxides, carbides, nitrides, and sulfides, have shown promise in balancing activity, durability, and affordability. The integration of nanostructuring techniques and computational modeling has enabled the design of catalysts with enhanced active site exposure and electronic properties. Furthermore, the Review highlights challenges such as material degradation, high overpotentials, and gas crossover, along with potential solutions like protective coatings, bifunctional catalysts, and advanced electrolyzer designs. Future prospects emphasize the role of artificial intelligence, hybrid systems, and sustainable manufacturing in accelerating progress. This comprehensive review underscores the significance of bridging fundamental research with technological innovations to scale up green hydrogen production, addressing energy demands while mitigating environmental impacts.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"37 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143872636","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 : 2025-04-25DOI: 10.1021/acs.langmuir.5c00740
Dung di Caprio, Abdelhafed Taleb, Fábio D. A. Aarão Reis
Materials with dendritic morphologies exhibit large surface areas that improve the catalytic, optical, and wetting properties but have ambiguous effects in batteries, so modeling their growth may help find the best operation conditions in each case. Kinetic Monte Carlo simulations are used here to study a metal electrodeposition model that represents the interplay between diffusive cation flux in the electrolyte and surface diffusion of adsorbed atoms (adatoms) with electrodes perpendicular to the gradient of the electrolyte concentration and different crystallographic orientations. In FCC lattices, dendrites with a pine tree shape are formed for all orientations, with dominant (111) surfaces and with trunks propagating in [001] and equivalent directions. However, with (110) and (111) substrates, secondary branches do not grow because the inclined primary branches block the cation flux (shadowing effect), so the dendrites may have a leaf-like shape. Some morphologies obtained here resemble those of the silver and gold electrodeposits. The extension to electrodeposition of HCP crystals with (0001) substrates shows the formation of leaf-like dendrites with a hexagonal symmetry. In both lattices, hierarchically organized structures appear for model parameters that warrant large diffusion lengths of adsorbed atoms on flat planes (typically coordination numbers n ≤ 4) and their stability at low-energy configurations (n ≥ 7). Average dendrite widths scale approximately with the diffusion length from adsorption to permanent incorporation to the crystal. These results show that dendrite widths are directly related to the relaxation of the electrodeposited material, and their crystallography is controlled by the energetics of the relaxation, but their visual appearance may depend on their angles with the electrode. In the range of model parameters where the coordination number weakly affects the diffusion of adsorbed atoms, the dendrites become rounded and have flower-like shapes. Possible effects of the orientation on the physicochemical properties of thin dendritic films are discussed.
{"title":"Relaxation of the Adsorbed Material and Shadowing Effects on the Shape and Size of Electrodeposited Dendrites","authors":"Dung di Caprio, Abdelhafed Taleb, Fábio D. A. Aarão Reis","doi":"10.1021/acs.langmuir.5c00740","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00740","url":null,"abstract":"Materials with dendritic morphologies exhibit large surface areas that improve the catalytic, optical, and wetting properties but have ambiguous effects in batteries, so modeling their growth may help find the best operation conditions in each case. Kinetic Monte Carlo simulations are used here to study a metal electrodeposition model that represents the interplay between diffusive cation flux in the electrolyte and surface diffusion of adsorbed atoms (adatoms) with electrodes perpendicular to the gradient of the electrolyte concentration and different crystallographic orientations. In FCC lattices, dendrites with a pine tree shape are formed for all orientations, with dominant (111) surfaces and with trunks propagating in [001] and equivalent directions. However, with (110) and (111) substrates, secondary branches do not grow because the inclined primary branches block the cation flux (shadowing effect), so the dendrites may have a leaf-like shape. Some morphologies obtained here resemble those of the silver and gold electrodeposits. The extension to electrodeposition of HCP crystals with (0001) substrates shows the formation of leaf-like dendrites with a hexagonal symmetry. In both lattices, hierarchically organized structures appear for model parameters that warrant large diffusion lengths of adsorbed atoms on flat planes (typically coordination numbers <i>n</i> ≤ 4) and their stability at low-energy configurations (<i>n</i> ≥ 7). Average dendrite widths scale approximately with the diffusion length from adsorption to permanent incorporation to the crystal. These results show that dendrite widths are directly related to the relaxation of the electrodeposited material, and their crystallography is controlled by the energetics of the relaxation, but their visual appearance may depend on their angles with the electrode. In the range of model parameters where the coordination number weakly affects the diffusion of adsorbed atoms, the dendrites become rounded and have flower-like shapes. Possible effects of the orientation on the physicochemical properties of thin dendritic films are discussed.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"35 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876265","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 : 2025-04-25DOI: 10.1021/acs.langmuir.5c00662
Maximilian Winzely, Adam H. Clark, Deema Balalta, Piyush Chauhan, Paul M. Leidinger, Meriem Fikry, Tym de Wild, Maximilian Georgi, Alexander Eychmüller, Sara Bals, Thomas J. Schmidt, Juan Herranz
The electrochemical reduction of CO2 is a promising approach to mitigate global warming by converting CO2 into valuable industrial chemicals such as CO. Among the various CO2-electroreduction catalysts investigated, AuCu alloys have proven to be particularly promising as they exhibit even higher activity and selectivity toward CO production compared to pure Au, which can be considered as one of the state-of-the-art catalysts for this reaction. In a recent study, we showed that unsupported AuCu aerogels feature an appealing CO2-to-CO activity and selectivity, even if in their as-synthesized form they were not phase-pure but instead contained Cu oxide. Thus, in this work, we aim at understanding how the transformation of this bimetallic and compositionally heterogeneous aerogel induced by a cyclic voltammetry (CV) treatment leads to this enhanced CO2-electroreduction performance. This was done by applying three different experimental protocols, implying (i) the absence of this CV treatment, (ii) the completion of the CV treatment without exchanging the electrolyte prior to the CO2-reduction test, or (iii) the CV treatment and exchanging the electrolyte before performing the CO2-reduction potential hold. These three protocols were complemented with operando grazing incidence X-ray absorption spectroscopy (GIXAS) measurements that revealed the structural and compositional changes undergone by the AuCu aerogel during CV treatment. The latter is then shown to lead to the removal of Cu oxide side phases and the enrichment of the aerogel’s surface with Au atoms and a AuCu alloy phase, which in turn results in a significant increase in the faradaic efficiency toward CO, from 23 to 81% when this CV treatment is overlooked vs performed, respectively.
{"title":"Monitoring the Activation of a AuCu Aerogel CO2-Reduction Electrocatalyst via Operando XAS","authors":"Maximilian Winzely, Adam H. Clark, Deema Balalta, Piyush Chauhan, Paul M. Leidinger, Meriem Fikry, Tym de Wild, Maximilian Georgi, Alexander Eychmüller, Sara Bals, Thomas J. Schmidt, Juan Herranz","doi":"10.1021/acs.langmuir.5c00662","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00662","url":null,"abstract":"The electrochemical reduction of CO<sub>2</sub> is a promising approach to mitigate global warming by converting CO<sub>2</sub> into valuable industrial chemicals such as CO. Among the various CO<sub>2</sub>-electroreduction catalysts investigated, AuCu alloys have proven to be particularly promising as they exhibit even higher activity and selectivity toward CO production compared to pure Au, which can be considered as one of the state-of-the-art catalysts for this reaction. In a recent study, we showed that unsupported AuCu aerogels feature an appealing CO<sub>2</sub>-to-CO activity and selectivity, even if in their as-synthesized form they were not phase-pure but instead contained Cu oxide. Thus, in this work, we aim at understanding how the transformation of this bimetallic and compositionally heterogeneous aerogel induced by a cyclic voltammetry (CV) treatment leads to this enhanced CO<sub>2</sub>-electroreduction performance. This was done by applying three different experimental protocols, implying (i) the absence of this CV treatment, (ii) the completion of the CV treatment without exchanging the electrolyte prior to the CO<sub>2</sub>-reduction test, or (iii) the CV treatment and exchanging the electrolyte before performing the CO<sub>2</sub>-reduction potential hold. These three protocols were complemented with <i>operando</i> grazing incidence X-ray absorption spectroscopy (GIXAS) measurements that revealed the structural and compositional changes undergone by the AuCu aerogel during CV treatment. The latter is then shown to lead to the removal of Cu oxide side phases and the enrichment of the aerogel’s surface with Au atoms and a AuCu alloy phase, which in turn results in a significant increase in the faradaic efficiency toward CO, from 23 to 81% when this CV treatment is overlooked vs performed, respectively.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"7 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876262","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 : 2025-04-25DOI: 10.1021/acs.langmuir.5c00292
Akhil Dilipkumar, Anshu Shukla, Dan Zhao, Shamsuzzaman Farooq
CALF–20 is a hydrophobic MOF adsorbent demonstrated at a pilot scale for the capture of CO2 from wet flue gas using a direct steam heating TSA cycle. It has been synthesized following a published protocol, and its XRD structure matches known results. Both crystals and particles are used to study single-component adsorption and the diffusion of CO2, N2, and H2O by using gravimetric, volumetric, and dynamic column breakthrough methods. Temperature and relative humidity ranges explored are 25–150 °C and 0–95% in helium, respectively, up to 1 bar pressure. A steam–helium mixture is used above 100 °C. Small pressure steps are used to determine (approximately) locally constant transport parameters. The Sips–Henry isotherm is the best-fit model, which correctly captures the dependence of the isosteric heat of adsorption on adsorbent loading, especially the complex shape for H2O. The pore diffusion model captures crystal uptakes. The micropore diffusivity is an increasing function of the adsorbed-phase concentration up to a certain level before showing reversal, which is consistent with the Darken equation, a function of isotherm curvature. Gas/moisture transport in CALF–20 particles is controlled by Knudsen diffusion in the macropores. The key features observed from the single-component adsorption and diffusion studies and their impact on process studies are demonstrated by applying them to predict breakthrough results.
{"title":"Adsorption Equilibrium and Transport of CO2, N2, and H2O in CALF–20","authors":"Akhil Dilipkumar, Anshu Shukla, Dan Zhao, Shamsuzzaman Farooq","doi":"10.1021/acs.langmuir.5c00292","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00292","url":null,"abstract":"CALF–20 is a hydrophobic MOF adsorbent demonstrated at a pilot scale for the capture of CO<sub>2</sub> from wet flue gas using a direct steam heating TSA cycle. It has been synthesized following a published protocol, and its XRD structure matches known results. Both crystals and particles are used to study single-component adsorption and the diffusion of CO<sub>2</sub>, N<sub>2</sub>, and H<sub>2</sub>O by using gravimetric, volumetric, and dynamic column breakthrough methods. Temperature and relative humidity ranges explored are 25–150 °C and 0–95% in helium, respectively, up to 1 bar pressure. A steam–helium mixture is used above 100 °C. Small pressure steps are used to determine (approximately) locally constant transport parameters. The Sips–Henry isotherm is the best-fit model, which correctly captures the dependence of the isosteric heat of adsorption on adsorbent loading, especially the complex shape for H<sub>2</sub>O. The pore diffusion model captures crystal uptakes. The micropore diffusivity is an increasing function of the adsorbed-phase concentration up to a certain level before showing reversal, which is consistent with the Darken equation, a function of isotherm curvature. Gas/moisture transport in CALF–20 particles is controlled by Knudsen diffusion in the macropores. The key features observed from the single-component adsorption and diffusion studies and their impact on process studies are demonstrated by applying them to predict breakthrough results.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"8 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876264","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}
Photocatalytic CO2 reduction provides a sustainable route to combat climate change by converting CO2 into valuable chemicals by using sunlight. This study presents both experimental and theoretical insights into the reduction of CO2 to HCOOH using biomass-derived carbon dots embedded onto phytochemical-based CdS quantum dots. The 0D CDs/CdS QDs(bio) composites exhibit rich sulfur vacancies and a more negative conduction band, effectively inhibiting CdS photocorrosion (SO42–) while enhancing the CO2 adsorption and photocurrent response. Additionally, it reduced PL intensity and increased decay time, suggesting the enhancement of charge separation and suppression of charge recombination. The optimal 0.4CDs/CdS QDs(bio) composite exhibited a remarkable CO2 reduction to HCOOH formation yield of 439.51 μmol g–1 h–1 (apparent quantum yield of 3.81%) while retaining its structural and morphological stability. Density functional theory calculations reveal HCOO* as a key intermediate, confirming the thermodynamic preference for HCOOH formation over CO with a free energy change of −0.71 eV. This study introduces a novel bio-based CdS QDs composite modified with biomass-derived CDs, providing mechanistic insights into photocatalytic CO2 reduction for sustainable fuel production.
{"title":"Experimental and Theoretical Studies on Photocatalytic CO2 Reduction to HCOOH by Biomass-Derived Carbon Dots Embedded Phytochemical-Based CdS Quantum Dots","authors":"Pramod Madhukar Gawal, Jumana Ishrat, Kalishankar Bhattacharyya, Animes Kumar Golder","doi":"10.1021/acs.langmuir.5c01002","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c01002","url":null,"abstract":"Photocatalytic CO<sub>2</sub> reduction provides a sustainable route to combat climate change by converting CO<sub>2</sub> into valuable chemicals by using sunlight. This study presents both experimental and theoretical insights into the reduction of CO<sub>2</sub> to HCOOH using biomass-derived carbon dots embedded onto phytochemical-based CdS quantum dots. The 0D CDs/CdS QDs(bio) composites exhibit rich sulfur vacancies and a more negative conduction band, effectively inhibiting CdS photocorrosion (SO<sub>4</sub><sup>2–</sup>) while enhancing the CO<sub>2</sub> adsorption and photocurrent response. Additionally, it reduced PL intensity and increased decay time, suggesting the enhancement of charge separation and suppression of charge recombination. The optimal 0.4CDs/CdS QDs(bio) composite exhibited a remarkable CO<sub>2</sub> reduction to HCOOH formation yield of 439.51 μmol g<sup>–1</sup> h<sup>–1</sup> (apparent quantum yield of 3.81%) while retaining its structural and morphological stability. Density functional theory calculations reveal HCOO* as a key intermediate, confirming the thermodynamic preference for HCOOH formation over CO with a free energy change of −0.71 eV. This study introduces a novel bio-based CdS QDs composite modified with biomass-derived CDs, providing mechanistic insights into photocatalytic CO<sub>2</sub> reduction for sustainable fuel production.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"24 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876267","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 : 2025-04-24DOI: 10.1021/acs.langmuir.5c00478
Marco Pierau, Simon Kriegler, Clara Rickhoff, Tiffany O. Paulisch, Tristan Wegner, Azadeh Alavizargar, Andreas Heuer, Roland Winter, Frank Glorius
In recent years, a variety of lipid-mimetic imidazolium salts have been developed and applied to investigate biological membranes and related processes. Despite their overall similar properties to natural lipids, there are potential drawbacks including cytotoxicity attributed to the cationic charge. Herein, we report the investigation of a novel class of electronically neutral imidazole-based lipids. In comparison to their positively charged congeners, they show improved biophysical properties and higher similarity to native lipids. By employing calorimetry, fluorescence spectroscopies, and fluorescence and atomic force microscopy, we examined changes in the thermotropic phase behavior, lipid order parameter, fluidity, and lateral membrane organization upon incorporation of the lipid mimetics. Depending on the characteristic of the lipid chains, charge of the headgroup, and substitution pattern, we observed changes in lipid order and fluidity, thus allowing modulation and fine-tuning of the physicochemical properties of the modified membrane. Notably, a newly synthesized imidazole-based cholesterol showed membrane properties very similar to natural cholesterol. Extensive computational studies indicate effective mimicking of cholesterol and reveal its capability to participate in raft formation. This new class of neutral imidazole lipid analogues is expected to lead to better molecular probes and tools.
{"title":"Neutral Imidazole Lipid Analogues Exhibit Improved Properties for Artificial Model Biomembranes","authors":"Marco Pierau, Simon Kriegler, Clara Rickhoff, Tiffany O. Paulisch, Tristan Wegner, Azadeh Alavizargar, Andreas Heuer, Roland Winter, Frank Glorius","doi":"10.1021/acs.langmuir.5c00478","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00478","url":null,"abstract":"In recent years, a variety of lipid-mimetic imidazolium salts have been developed and applied to investigate biological membranes and related processes. Despite their overall similar properties to natural lipids, there are potential drawbacks including cytotoxicity attributed to the cationic charge. Herein, we report the investigation of a novel class of electronically neutral imidazole-based lipids. In comparison to their positively charged congeners, they show improved biophysical properties and higher similarity to native lipids. By employing calorimetry, fluorescence spectroscopies, and fluorescence and atomic force microscopy, we examined changes in the thermotropic phase behavior, lipid order parameter, fluidity, and lateral membrane organization upon incorporation of the lipid mimetics. Depending on the characteristic of the lipid chains, charge of the headgroup, and substitution pattern, we observed changes in lipid order and fluidity, thus allowing modulation and fine-tuning of the physicochemical properties of the modified membrane. Notably, a newly synthesized imidazole-based cholesterol showed membrane properties very similar to natural cholesterol. Extensive computational studies indicate effective mimicking of cholesterol and reveal its capability to participate in raft formation. This new class of neutral imidazole lipid analogues is expected to lead to better molecular probes and tools.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"33 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143872641","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 : 2025-04-24DOI: 10.1021/acs.langmuir.5c00065
Wei Hu, Yang Yang, Yunan Li, Fei Xu, Fubing Bao, Zhekai Gao, Xiaolong Li, Xiaoyan Gao
The study developed a thermoresponsive film to achieve autonomous fluid driving in microfluidic channels, simplify microfluidic systems, and improve their operability. This film has a lower critical solution temperature (LCST), exhibiting different wettabilities on each side of the LCST, and showed improved hydrophilicity-to-hydrophobicity conversion with increased substrate roughness, maintaining stability after repeated cycles. The thermoresponsive film was applied to the inner wall of the glass capillary, which showed a hydrophilic and enhanced capillary effect below the LCST and a hydrophobic and weakened capillary effect above the LCST. Subsequently, the modified capillary was placed under a dynamic temperature gradient, and the force analysis of the fluid in the flow channel was carried out. It was found that only when the driving force exceeded the axial resistance could the fluid migrate. Experimental analysis showed that fluid length was directly proportional to axial resistance and inversely proportional to both driving force and migration velocity at a constant dynamic temperature gradient. Additionally, the temperature of the hot end of the capillary was varied to form different dynamic temperature gradients. A higher dynamic temperature gradient resulted in greater fluid displacement and velocity at a constant fluid length. The results presented in this study were expected to provide new insights into the design and optimization of thermally driven microfluidic systems.
{"title":"Thermoresponsive Film Enhances Fluid Migration within the Capillary under a Dynamic Wettability Gradient","authors":"Wei Hu, Yang Yang, Yunan Li, Fei Xu, Fubing Bao, Zhekai Gao, Xiaolong Li, Xiaoyan Gao","doi":"10.1021/acs.langmuir.5c00065","DOIUrl":"https://doi.org/10.1021/acs.langmuir.5c00065","url":null,"abstract":"The study developed a thermoresponsive film to achieve autonomous fluid driving in microfluidic channels, simplify microfluidic systems, and improve their operability. This film has a lower critical solution temperature (LCST), exhibiting different wettabilities on each side of the LCST, and showed improved hydrophilicity-to-hydrophobicity conversion with increased substrate roughness, maintaining stability after repeated cycles. The thermoresponsive film was applied to the inner wall of the glass capillary, which showed a hydrophilic and enhanced capillary effect below the LCST and a hydrophobic and weakened capillary effect above the LCST. Subsequently, the modified capillary was placed under a dynamic temperature gradient, and the force analysis of the fluid in the flow channel was carried out. It was found that only when the driving force exceeded the axial resistance could the fluid migrate. Experimental analysis showed that fluid length was directly proportional to axial resistance and inversely proportional to both driving force and migration velocity at a constant dynamic temperature gradient. Additionally, the temperature of the hot end of the capillary was varied to form different dynamic temperature gradients. A higher dynamic temperature gradient resulted in greater fluid displacement and velocity at a constant fluid length. The results presented in this study were expected to provide new insights into the design and optimization of thermally driven microfluidic systems.","PeriodicalId":50,"journal":{"name":"Langmuir","volume":"27 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143867154","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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