Batuhan Mulla, Kyriacos Ioannou, Gkerman Kotanidis, Ioannis Ioannidis, Georgios Constantinides, M. Baker, S. Hinder, Christian Mitterer, Ioannis Pashalidis, Nikolaos Kostoglou, Claus Rebholz
The removal of contaminants from aqueous solutions by adsorption onto carbonaceous materials has attracted increasing interest in recent years. In this study, pristine and oxidized activated carbon (AC) fabrics with different surface textures and porosity characteristics were used for the removal of crystal violet (CV) dye from aqueous solutions. Batch adsorption experiments were performed to investigate the CV adsorption performance of the AC fabrics in terms of contact time, temperature, adsorbate concentration and adsorbent amount. Evaluation of the thermodynamic parameters and the adsorption performance of the AC fabrics in ground water and sea water solutions were also carried out. Langmuir isotherm model, pseudo first and pseudo second order kinetics models were utilized to analyze and fit the adsorption data. The introduction of oxygen-based functional groups on the surface of AC fabrics was carried out through a nitric acid treatment. This oxidation process resulted in a significant reduction in the surface area and pore volume, along with a small increase in the average pore size and a significant enhancement in the CV adsorption capacity, indicating that the dye molecules are mainly adsorbed on the external surface of the carbon fabrics. The herein evaluated 428 mg/g adsorption capacity at 55 °C for the oxidized non-woven AC fabric is one of the highest adsorption capacity values reported in the literature for CV removal using AC materials. Thermodynamic studies showed that the adsorption occurs spontaneously and is an endothermic and entropy-driven reaction. Furthermore, pristine and oxidized non-woven AC fabrics displayed more than 90% CV uptake from sea water samples, underlining the great potential these fabrics possess for the removal of dyes from natural/multicomponent waters.
近年来，通过碳质材料吸附去除水溶液中污染物的研究越来越受到关注。本研究利用具有不同表面纹理和孔隙率特征的原始活性炭和氧化活性炭织物去除水溶液中的结晶紫（CV）染料。批量吸附实验研究了活性炭织物在接触时间、温度、吸附剂浓度和吸附剂用量方面的 CV 吸附性能。此外，还对 AC 织物在地下水和海水溶液中的热力学参数和吸附性能进行了评估。利用 Langmuir 等温线模型、伪一阶和伪二阶动力学模型来分析和拟合吸附数据。通过硝酸处理，在 AC 织物表面引入了氧官能团。这一氧化过程导致表面积和孔隙率显著减少，平均孔径略有增加，CV 吸附能力显著提高，表明染料分子主要吸附在碳织物的外表面。经评估，氧化无纺 AC 织物在 55 °C 时的吸附容量为 428 mg/g，是文献报道的使用 AC 材料去除 CV 的最高吸附容量值之一。热力学研究表明，吸附是自发发生的，是一种内热和熵驱动反应。此外，原始无纺布和氧化无纺布对海水样本中 CV 的吸附率超过 90%，凸显了这些无纺布在去除天然/多组分水体中的染料方面所具有的巨大潜力。
{"title":"Removal of Crystal Violet Dye from Aqueous Solutions through Adsorption onto Activated Carbon Fabrics","authors":"Batuhan Mulla, Kyriacos Ioannou, Gkerman Kotanidis, Ioannis Ioannidis, Georgios Constantinides, M. Baker, S. Hinder, Christian Mitterer, Ioannis Pashalidis, Nikolaos Kostoglou, Claus Rebholz","doi":"10.3390/c10010019","DOIUrl":"https://doi.org/10.3390/c10010019","url":null,"abstract":"The removal of contaminants from aqueous solutions by adsorption onto carbonaceous materials has attracted increasing interest in recent years. In this study, pristine and oxidized activated carbon (AC) fabrics with different surface textures and porosity characteristics were used for the removal of crystal violet (CV) dye from aqueous solutions. Batch adsorption experiments were performed to investigate the CV adsorption performance of the AC fabrics in terms of contact time, temperature, adsorbate concentration and adsorbent amount. Evaluation of the thermodynamic parameters and the adsorption performance of the AC fabrics in ground water and sea water solutions were also carried out. Langmuir isotherm model, pseudo first and pseudo second order kinetics models were utilized to analyze and fit the adsorption data. The introduction of oxygen-based functional groups on the surface of AC fabrics was carried out through a nitric acid treatment. This oxidation process resulted in a significant reduction in the surface area and pore volume, along with a small increase in the average pore size and a significant enhancement in the CV adsorption capacity, indicating that the dye molecules are mainly adsorbed on the external surface of the carbon fabrics. The herein evaluated 428 mg/g adsorption capacity at 55 °C for the oxidized non-woven AC fabric is one of the highest adsorption capacity values reported in the literature for CV removal using AC materials. Thermodynamic studies showed that the adsorption occurs spontaneously and is an endothermic and entropy-driven reaction. Furthermore, pristine and oxidized non-woven AC fabrics displayed more than 90% CV uptake from sea water samples, underlining the great potential these fabrics possess for the removal of dyes from natural/multicomponent waters.","PeriodicalId":9397,"journal":{"name":"C","volume":"492 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140446834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polypyrrole films are commonly prepared as conductive electrode surfaces for a variety of applications. Recently, there has been increasing interest in improving the adhesive properties and biocompatibility of polypyrrole electrodes via the incorporation of bioinspired polydopamine within the polymer scaffold. However, very little is currently known about the structural effects of polydopamine incorporation during the electropolymerisation of hybrid films. In this work, we combine electrochemical quartz crystal microbalance studies, fundamental electrochemical characterisation, atomic force microscopy, and a suite of spectroscopic techniques in order to correlate changes in the structure and performance of polypyrrole–polydopamine films to the structural modifications of the nanostructure induced by polydopamine incorporation. The results indicate that polydopamine incorporation greatly increases the rate of hybrid film deposition, as well as improving adhesion, surface homogeneity, and wettability, with no compromise in charge transfer properties. Polydopamine incorporation is strongly suggested to occur in non-connected domains within a predominantly polypyrrole-like scaffold. We propose a two-step model of co-polymerisation and the subsequent surface adhesion of hybrid films. Results are expected to be of broad general interest to researchers utilizing polypyrrole and polydopamine to prepare tailor-made electrodes for biosensing and catalysis.
{"title":"Effects of Polydopamine Incorporation on the Nanostructure and Electrochemical Performance of Electrodeposited Polypyrrole Films","authors":"James A. Behan, Frédéric Barrière","doi":"10.3390/c10010020","DOIUrl":"https://doi.org/10.3390/c10010020","url":null,"abstract":"Polypyrrole films are commonly prepared as conductive electrode surfaces for a variety of applications. Recently, there has been increasing interest in improving the adhesive properties and biocompatibility of polypyrrole electrodes via the incorporation of bioinspired polydopamine within the polymer scaffold. However, very little is currently known about the structural effects of polydopamine incorporation during the electropolymerisation of hybrid films. In this work, we combine electrochemical quartz crystal microbalance studies, fundamental electrochemical characterisation, atomic force microscopy, and a suite of spectroscopic techniques in order to correlate changes in the structure and performance of polypyrrole–polydopamine films to the structural modifications of the nanostructure induced by polydopamine incorporation. The results indicate that polydopamine incorporation greatly increases the rate of hybrid film deposition, as well as improving adhesion, surface homogeneity, and wettability, with no compromise in charge transfer properties. Polydopamine incorporation is strongly suggested to occur in non-connected domains within a predominantly polypyrrole-like scaffold. We propose a two-step model of co-polymerisation and the subsequent surface adhesion of hybrid films. Results are expected to be of broad general interest to researchers utilizing polypyrrole and polydopamine to prepare tailor-made electrodes for biosensing and catalysis.","PeriodicalId":9397,"journal":{"name":"C","volume":"92 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140449327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monolayer graphene absorbs 2.3 percent of the incident visible light. This “small” absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method’s validity experimentally. We quantitatively explain the measured contrasts of multilayer graphene on SiO2/Si substrates and find sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.
{"title":"Introducing Corrections to the Reflectance of Graphene by Light Emission","authors":"Ken-ichi Sasaki, Kenichi Hitachi, Masahiro Kamada, Takamoto Yokosawa, T. Ochi, Tomohiro Matsui","doi":"10.3390/c10010018","DOIUrl":"https://doi.org/10.3390/c10010018","url":null,"abstract":"Monolayer graphene absorbs 2.3 percent of the incident visible light. This “small” absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method’s validity experimentally. We quantitatively explain the measured contrasts of multilayer graphene on SiO2/Si substrates and find sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.","PeriodicalId":9397,"journal":{"name":"C","volume":"255 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139835914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Monolayer graphene absorbs 2.3 percent of the incident visible light. This “small” absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method’s validity experimentally. We quantitatively explain the measured contrasts of multilayer graphene on SiO2/Si substrates and find sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.
{"title":"Introducing Corrections to the Reflectance of Graphene by Light Emission","authors":"Ken-ichi Sasaki, Kenichi Hitachi, Masahiro Kamada, Takamoto Yokosawa, T. Ochi, Tomohiro Matsui","doi":"10.3390/c10010018","DOIUrl":"https://doi.org/10.3390/c10010018","url":null,"abstract":"Monolayer graphene absorbs 2.3 percent of the incident visible light. This “small” absorption has been used to emphasize the visual transparency of graphene, but it in fact means that multilayer graphene absorbs a sizable fraction of incident light, which causes non-negligible fluorescence. In this paper, we formulate the light emission properties of multilayer graphene composed of tens to hundreds of layers using a transfer matrix method and confirm the method’s validity experimentally. We quantitatively explain the measured contrasts of multilayer graphene on SiO2/Si substrates and find sizable corrections, which cannot be classified as incoherent light emissions, to the reflectance of visible light. The new component originates from coherent emission caused by absorption at each graphene layer. Multilayer graphene thus functions as a partial coherent light source of various wavelengths, and it may have surface-emitting laser applications.","PeriodicalId":9397,"journal":{"name":"C","volume":"24 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139776306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prakash Giri, Irwin Gill, Morgan Swensgard, Alexandra Kaiser, Audrey Rust, Brian Stuparyk, Andrew Fisher, Justice Williams, Katie Renoit, Eleanor Kreeb, Corentin Lavenan, Mark J. Schulz
A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.
{"title":"Pristine and Coated Carbon Nanotube Sheets—Characterization and Potential Applications","authors":"Prakash Giri, Irwin Gill, Morgan Swensgard, Alexandra Kaiser, Audrey Rust, Brian Stuparyk, Andrew Fisher, Justice Williams, Katie Renoit, Eleanor Kreeb, Corentin Lavenan, Mark J. Schulz","doi":"10.3390/c10010017","DOIUrl":"https://doi.org/10.3390/c10010017","url":null,"abstract":"A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.","PeriodicalId":9397,"journal":{"name":"C","volume":" 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139789619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Prakash Giri, Irwin Gill, Morgan Swensgard, Alexandra Kaiser, Audrey Rust, Brian Stuparyk, Andrew Fisher, Justice Williams, Katie Renoit, Eleanor Kreeb, Corentin Lavenan, Mark J. Schulz
A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.
{"title":"Pristine and Coated Carbon Nanotube Sheets—Characterization and Potential Applications","authors":"Prakash Giri, Irwin Gill, Morgan Swensgard, Alexandra Kaiser, Audrey Rust, Brian Stuparyk, Andrew Fisher, Justice Williams, Katie Renoit, Eleanor Kreeb, Corentin Lavenan, Mark J. Schulz","doi":"10.3390/c10010017","DOIUrl":"https://doi.org/10.3390/c10010017","url":null,"abstract":"A carbon nanotube (CNT) sheet is a nonwoven fabric that is being evaluated for use in different textile applications. Several properties of pristine CNT sheets and CNT sheets coated with a polysilazane sealant and coating were measured and compared in the paper. The polysilazane coating is used to reduce the shedding of CNT fibers from the sheet when the sheet is in contact with surfaces. Most fabrics show some shedding of fibers during the washing or abrasion of the fabric. This study showed that the coating reduces the shedding of fibers from CNT fabric. The coating also increased the flame resistance of the fabric. The pristine and coated sheets both have low strength but high strain to failure. The pristine and coated CNT sheet densities are 0.48 g/cc and 0.65 g/cc, respectively. The pristine CNT sheet is approximately 27 μ thick. The coated sheet is approximately 24 μ thick. The coating may have densified the sheet, making it thinner. The thickness of the compliant sheets was difficult to measure and is a source of error in the properties. Characterization results are given in this paper. The results are for comparison purposes and not to establish material properties data. Possible applications for CNT sheets are briefly discussed.","PeriodicalId":9397,"journal":{"name":"C","volume":"37 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139849428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings’ CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts.
电气化程度的提高大大增加了对高效耐用电接触材料的需求。碳纳米颗粒（CNP）是一种很有前途的涂层材料，因为它们具有固有的传输特性（从而最大限度地减少对导电性的影响）、经证实的固体润滑性（可能改善摩擦学性能）和疏水润湿行为（可能提供大气保护）。在本研究中，通过在镀银表面电泳沉积碳纳米管和纳米角涂层，然后进行三电和润湿表征。所提出的涂层不会对基底的导电性产生负面影响，其电阻值与未涂层的参考值相当。三电特性分析表明，涂层可减少摩擦测试中的粘合剂磨损，同时保持稳定恒定的电接触电阻。此外，CNP 涂层表面对水具有疏水性润湿行为，石墨和碳纳米管 (CNT) 涂层接近超疏水性。在无柄水滴测试中，长时间接触水滴会导致接触角（CA）测量值减小；但 CNT 涂层在五分钟后的 CA 值减小仅约为 5°。因此，CNP（特别是 CNT）涂层在用作电气触点的磨损和大气保护屏障方面显示出良好的应用效果。
{"title":"Comprehensive Study on Carbon-Coated Silver for Improved Tribo-Electrical and Wetting Performance","authors":"Bruno Alderete, F. Mücklich, S. Suárez","doi":"10.3390/c10010016","DOIUrl":"https://doi.org/10.3390/c10010016","url":null,"abstract":"The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings’ CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts.","PeriodicalId":9397,"journal":{"name":"C","volume":"8 7-8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139867322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings’ CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts.
电气化程度的提高大大增加了对高效耐用电接触材料的需求。碳纳米颗粒（CNP）是一种很有前途的涂层材料，因为它们具有固有的传输特性（从而最大限度地减少对导电性的影响）、经证实的固体润滑性（可能改善摩擦学性能）和疏水润湿行为（可能提供大气保护）。在本研究中，通过在镀银表面电泳沉积碳纳米管和纳米角涂层，然后进行三电和润湿表征。所提出的涂层不会对基底的导电性产生负面影响，其电阻值与未涂层的参考值相当。三电特性分析表明，涂层可减少摩擦测试中的粘合剂磨损，同时保持稳定恒定的电接触电阻。此外，CNP 涂层表面对水具有疏水性润湿行为，石墨和碳纳米管 (CNT) 涂层接近超疏水性。在无柄水滴测试中，长时间接触水滴会导致接触角（CA）测量值减小；但 CNT 涂层在五分钟后的 CA 值减小仅约为 5°。因此，CNP（特别是 CNT）涂层在用作电气触点的磨损和大气保护屏障方面显示出良好的应用效果。
{"title":"Comprehensive Study on Carbon-Coated Silver for Improved Tribo-Electrical and Wetting Performance","authors":"Bruno Alderete, F. Mücklich, S. Suárez","doi":"10.3390/c10010016","DOIUrl":"https://doi.org/10.3390/c10010016","url":null,"abstract":"The rise in electrification has considerably increased the demand for high-efficiency and durable electrical contact materials. Carbon nanoparticles (CNP) are a promising coating material due to their intrinsic transport properties (thus minimizing the impact on conductivity), their proven solid lubricity (potentially improving tribological performance), and their hydrophobic wetting behavior (potentially providing atmospheric protection). In this study, carbon nanotube and nanohorn coatings are produced via electrophoretic deposition on silver-plated surfaces, followed by tribo-electrical and wetting characterization. The proposed coatings do not negatively affect the conductivity of the substrate, showing resistance values on par with the uncoated reference. Tribo-electrical characterization revealed that the coatings reduce adhesive wear during fretting tests while maintaining stable and constant electrical contact resistance. Furthermore, CNP-coated surfaces show a hydrophobic wetting behavior toward water, with graphite and carbon nanotube (CNT) coatings approaching super-hydrophobicity. Prolonged exposure to water droplets during sessile drop tests caused a reduction in contact angle (CA) measurement; however, CNT coatings’ CA reduction after five minutes was only approximately 5°. Accordingly, CNP (specifically CNT) coatings show auspicious results for their application as wear and atmospheric protective barriers in electrical contacts.","PeriodicalId":9397,"journal":{"name":"C","volume":"2010 34","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139807177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The technology called carbon capture, utilization, and storage (CCUS) is important for capturing CO2 emissions before they enter the air. Because everyone wants to stop global warming by reducing CO2 emissions, CCUS is an important and emerging technology that can help slow down climate change, lower emissions in many areas, and support the move toward a sustainable and carbon-neutral future. As CCUS technology and its adaptation increases, it is very important to pay attention to the CCUS risks from a supply chain (SC) point of view. The goal of this study was to identify CCUS supply chain risks and develop a conceptual framework (CF) that provides a structured approach to ensure safe and reliable CCUS supply chain operations. Therefore, this study analyzed the literature related to the SCs of different sectors and identified the SC risks, which was the foundation for CCUS SC risk identification. This study demonstrates that there is no research article that provides a comprehensive CCUS SC risk management framework that connects with risk management strategies. The conceptual framework that is proposed in this study connects CCUS SC functions, risks, and risk management strategies to construct a complete CCUS supply chain risk management system. Moreover, the CF provides guidelines for future research, which will enrich the CCUS supply chain risk management system as well as fight climate change.
{"title":"Carbon Capture, Utilization, and Storage Risks from Supply Chain Perspective: A Review of the Literature and Conceptual Framework Development","authors":"Md Ainul Kabir, S. Khan, G. Kabir","doi":"10.3390/c10010015","DOIUrl":"https://doi.org/10.3390/c10010015","url":null,"abstract":"The technology called carbon capture, utilization, and storage (CCUS) is important for capturing CO2 emissions before they enter the air. Because everyone wants to stop global warming by reducing CO2 emissions, CCUS is an important and emerging technology that can help slow down climate change, lower emissions in many areas, and support the move toward a sustainable and carbon-neutral future. As CCUS technology and its adaptation increases, it is very important to pay attention to the CCUS risks from a supply chain (SC) point of view. The goal of this study was to identify CCUS supply chain risks and develop a conceptual framework (CF) that provides a structured approach to ensure safe and reliable CCUS supply chain operations. Therefore, this study analyzed the literature related to the SCs of different sectors and identified the SC risks, which was the foundation for CCUS SC risk identification. This study demonstrates that there is no research article that provides a comprehensive CCUS SC risk management framework that connects with risk management strategies. The conceptual framework that is proposed in this study connects CCUS SC functions, risks, and risk management strategies to construct a complete CCUS supply chain risk management system. Moreover, the CF provides guidelines for future research, which will enrich the CCUS supply chain risk management system as well as fight climate change.","PeriodicalId":9397,"journal":{"name":"C","volume":"290 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140472233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neeraj Gupta, Ilaria Barlocco, O. Khavryuchenko, Alberto Villa
Nitrogen-rich carbon nanotubes NCNT700 and NCNT800 were prepared using the chemical vapor deposition method (CVD). The catalysts were characterized via high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Both the catalysts were found to have an inverted cup-stack-like morphology. The XPS analysis revealed that the catalysts are rich in pyridinic sites with variable amounts of nitrogen on their surface. The NCTN700, with a higher nitrogen content and more pyridinic sites on its surface, was found to be a good catalyst for the oxidation of benzyl and veratryl alcohols into respective aldehydes. It was observed that toluene and 4-methyl veratrole were also produced in this reaction. The amount of toluene produced was as high as 21%, with 99% conversion of benzaldehyde in the presence of NCNTs-700. The mechanistic pathway was revealed through DFT studies, where the unusual product formation of aromatic alkanes such as toluene and 4-methyl veratrole was explained during the reaction. It was astonishing to observe the reduced product in the reaction that proceeds in the forward direction in presence of a peroxide (tert-butyl hydroperoxide, TBHP). During the computational analysis, it was revealed that the reduced product observed in the reaction did not appear to proceed through a direct disproportionation reaction. Rather, the benzyl alcohol (the reactant) used in the reaction may undergo oxidation by releasing the hydrogen radicals. The hydrogen atoms released during the oxidation reaction appear to have been trapped on pyrrolic sites on the surface of catalyst and later transferred to the reactant molecules to produce toluene as a side product.
{"title":"Metal-Free Catalytic Conversion of Veratryl and Benzyl Alcohols through Nitrogen-Enriched Carbon Nanotubes","authors":"Neeraj Gupta, Ilaria Barlocco, O. Khavryuchenko, Alberto Villa","doi":"10.3390/c10010013","DOIUrl":"https://doi.org/10.3390/c10010013","url":null,"abstract":"Nitrogen-rich carbon nanotubes NCNT700 and NCNT800 were prepared using the chemical vapor deposition method (CVD). The catalysts were characterized via high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analysis. Both the catalysts were found to have an inverted cup-stack-like morphology. The XPS analysis revealed that the catalysts are rich in pyridinic sites with variable amounts of nitrogen on their surface. The NCTN700, with a higher nitrogen content and more pyridinic sites on its surface, was found to be a good catalyst for the oxidation of benzyl and veratryl alcohols into respective aldehydes. It was observed that toluene and 4-methyl veratrole were also produced in this reaction. The amount of toluene produced was as high as 21%, with 99% conversion of benzaldehyde in the presence of NCNTs-700. The mechanistic pathway was revealed through DFT studies, where the unusual product formation of aromatic alkanes such as toluene and 4-methyl veratrole was explained during the reaction. It was astonishing to observe the reduced product in the reaction that proceeds in the forward direction in presence of a peroxide (tert-butyl hydroperoxide, TBHP). During the computational analysis, it was revealed that the reduced product observed in the reaction did not appear to proceed through a direct disproportionation reaction. Rather, the benzyl alcohol (the reactant) used in the reaction may undergo oxidation by releasing the hydrogen radicals. The hydrogen atoms released during the oxidation reaction appear to have been trapped on pyrrolic sites on the surface of catalyst and later transferred to the reactant molecules to produce toluene as a side product.","PeriodicalId":9397,"journal":{"name":"C","volume":"72 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139593522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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