Pub Date : 2019-05-19DOI: 10.1177/1847980419844363
Alejandro Aranda, R. Landers, Patricio Carnelli, R. Candal, H. Alarcon, Juan M. Rodriguez
The present article examines the synthesis and characterization of zinc oxide nanorods grown on zinc oxide and silver nanoparticle seeds. Zinc oxide seeds were electrodeposited on a support of fluorine-doped tin oxide glass and heat-treated at 380°C. Silver nanoparticles were then deposited on this substrate, which was heat-treated at 160°C. Their presence was confirmed using ultraviolet–visible spectroscopy, by observing an absorption peak around 400 nm, corresponding to surface plasmon resonance. Growth of zinc oxide nanorods was achieved in a chemical bath at 90°C. The obtained films were analyzed by cyclic voltammetry, X-ray diffraction, and scanning electron microscopy. They consisted of zinc oxide with a Wurtzite-type crystal structure, arranged as nanorods of 50 nm. X-ray photoelectron spectroscopy exhibits peaks attributed to silver (0) and to the formation of silver oxide on the silver nanoparticle surface. In addition, two types of oxygen (O 1 s) were observed: oxygen from the crystalline network (O–2) and chemisorbed oxygen (–OH), for the seed and the nanorod films, respectively. The nanorods grown on zinc oxide seeds with silver deposits had a round shape and greater photoactivity than those grown without silver. This difference is attributed to the additional reflection that silver provides to the light reaching the film, thereby increasing the photogeneration from the charge carriers.
{"title":"Influence of silver electrochemically deposited onto zinc oxide seed nanoparticles on the photoelectrochemical performance of zinc oxide nanorod films","authors":"Alejandro Aranda, R. Landers, Patricio Carnelli, R. Candal, H. Alarcon, Juan M. Rodriguez","doi":"10.1177/1847980419844363","DOIUrl":"https://doi.org/10.1177/1847980419844363","url":null,"abstract":"The present article examines the synthesis and characterization of zinc oxide nanorods grown on zinc oxide and silver nanoparticle seeds. Zinc oxide seeds were electrodeposited on a support of fluorine-doped tin oxide glass and heat-treated at 380°C. Silver nanoparticles were then deposited on this substrate, which was heat-treated at 160°C. Their presence was confirmed using ultraviolet–visible spectroscopy, by observing an absorption peak around 400 nm, corresponding to surface plasmon resonance. Growth of zinc oxide nanorods was achieved in a chemical bath at 90°C. The obtained films were analyzed by cyclic voltammetry, X-ray diffraction, and scanning electron microscopy. They consisted of zinc oxide with a Wurtzite-type crystal structure, arranged as nanorods of 50 nm. X-ray photoelectron spectroscopy exhibits peaks attributed to silver (0) and to the formation of silver oxide on the silver nanoparticle surface. In addition, two types of oxygen (O 1 s) were observed: oxygen from the crystalline network (O–2) and chemisorbed oxygen (–OH), for the seed and the nanorod films, respectively. The nanorods grown on zinc oxide seeds with silver deposits had a round shape and greater photoactivity than those grown without silver. This difference is attributed to the additional reflection that silver provides to the light reaching the film, thereby increasing the photogeneration from the charge carriers.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980419844363","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43996258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-15DOI: 10.1177/1847980419840858
P. Kalakonda, S. Banne, P. Kalakonda
Carbon nanotubes are considered to be ideal candidates for improving the mechanical properties of polymer nanocomposite scaffolds due to their higher surface area, mechanical properties of three-dimensional isotropic structure, and physical properties. In this study, we showed the improved mechanical properties prepared by backfilling of preformed hydrogels and aerogels of individually dispersed multiwalled carbon nanotubes (MWCNTs-Baytubes) and thermoplastic polyurethane. Here, we used the solution-based fabrication method to prepare the composite scaffold and observed an improvement in tensile modulus about 200-fold over that of pristine polymer at 19 wt% MWCNT loading. Further, we tested the thermal properties of composite scaffolds and observed that the nanotube networks suppress the mobility of polymer chains, the composite scaffold samples were thermally stable well above their decomposition temperatures that extend the mechanical integrity of a polymer well above its polymer melting point. The improved mechanical properties of the composite scaffold might be useful in smart material industry.
{"title":"Enhanced mechanical properties of multiwalled carbon nanotubes/thermoplastic polyurethane nanocomposites","authors":"P. Kalakonda, S. Banne, P. Kalakonda","doi":"10.1177/1847980419840858","DOIUrl":"https://doi.org/10.1177/1847980419840858","url":null,"abstract":"Carbon nanotubes are considered to be ideal candidates for improving the mechanical properties of polymer nanocomposite scaffolds due to their higher surface area, mechanical properties of three-dimensional isotropic structure, and physical properties. In this study, we showed the improved mechanical properties prepared by backfilling of preformed hydrogels and aerogels of individually dispersed multiwalled carbon nanotubes (MWCNTs-Baytubes) and thermoplastic polyurethane. Here, we used the solution-based fabrication method to prepare the composite scaffold and observed an improvement in tensile modulus about 200-fold over that of pristine polymer at 19 wt% MWCNT loading. Further, we tested the thermal properties of composite scaffolds and observed that the nanotube networks suppress the mobility of polymer chains, the composite scaffold samples were thermally stable well above their decomposition temperatures that extend the mechanical integrity of a polymer well above its polymer melting point. The improved mechanical properties of the composite scaffold might be useful in smart material industry.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980419840858","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45486359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-03-18DOI: 10.1177/1847980419837821
Min Wang, Yanlin Zhang, C. Dong, Gang Chen, H. Guan
Here, the cobalt ferrite/carbon nanotubes nanocomposites were directly synthesized by a facile hydrothermal method at 200°C using benzyl alcohol as the solvent. The crystal and morphological structures as well as electromagnetic shielding performance at Ku band (12–18 GHz) were thoroughly investigated. Cobalt ferrite nanoparticles with a diameter around 6–10 nm were anchored on the surface of carbon nanotubes with some aggregation. It is found that the as-prepared nanocomposites exhibit excellent electromagnetic shielding performance with values 22–25 dB in the Ku frequency range with a thickness of 2 mm. The small cobalt ferrite nanoparticles offer a large number of polarization and magnetization active sites to improve the electromagnetic performance by the incorporation of carbon nanotubes.
{"title":"Preparation and electromagnetic shielding effectiveness of cobalt ferrite nanoparticles/carbon nanotubes composites","authors":"Min Wang, Yanlin Zhang, C. Dong, Gang Chen, H. Guan","doi":"10.1177/1847980419837821","DOIUrl":"https://doi.org/10.1177/1847980419837821","url":null,"abstract":"Here, the cobalt ferrite/carbon nanotubes nanocomposites were directly synthesized by a facile hydrothermal method at 200°C using benzyl alcohol as the solvent. The crystal and morphological structures as well as electromagnetic shielding performance at Ku band (12–18 GHz) were thoroughly investigated. Cobalt ferrite nanoparticles with a diameter around 6–10 nm were anchored on the surface of carbon nanotubes with some aggregation. It is found that the as-prepared nanocomposites exhibit excellent electromagnetic shielding performance with values 22–25 dB in the Ku frequency range with a thickness of 2 mm. The small cobalt ferrite nanoparticles offer a large number of polarization and magnetization active sites to improve the electromagnetic performance by the incorporation of carbon nanotubes.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980419837821","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48344510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-02-01DOI: 10.1177/1847980419827171
J. C. Ng, C. Y. Tan, B. Ong, A. Matsuda, W. Basirun, W. K. Tan, Ramesh Singh, B. Yap
In spite of advantages of direct methanol fuel cells, low methanol oxidation reaction and fuel crossover from anode to cathode, there remains a challenge that inhibits it from being commercialized. Active electrocatalysts are in high demand to promote the methanol oxidation reaction. The methanol reached at the anode can be immediately reacted, and thus, less methanol to cross to the cathode. The performance of electrocatalysts can be significantly influenced by varying the concentration of precursor solution. Theoretically, concentrated precursor solution facilitates rapid nucleation and growth; diluted precursor solution causes slow nucleation and growth. Rapid nucleation and slow growth have positive effect on the size of electrocatalysts which plays a significant role in the catalytic performance. Upon the addition of appropriate concentration of graphene oxide, the graphene oxide was reported to have stabilizing effect towards the catalyst nanoparticles. This work synthesized reduced graphene oxide–supported palladium electrocatalysts at different concentrations (0.5, 1.0, 2.0, 3.0 and 4.0 mg mL−1) with fixed volume and mass ratio of reduced graphene oxide to palladium by microwave-assisted reduction method. Results showed that reduced graphene oxide–supported palladium synthesized at a concentration of 1.0 mg mL−1 gave the best methanol oxidation reactivity (405.37 mA mg−1) and largest electrochemical active surface area (83.57 m2 g−1).
尽管直接甲醇燃料电池具有甲醇氧化反应低、燃料从阳极到阴极交叉等优点，但仍存在阻碍其商业化的挑战。催化甲醇氧化反应对活性电催化剂的需求很大。到达阳极的甲醇可以立即反应，因此，较少的甲醇穿过阴极。前驱体溶液浓度的变化对电催化剂的性能有显著影响。理论上，浓缩的前驱体溶液有利于快速成核和生长;稀释的前驱体溶液导致成核和生长缓慢。快速成核和缓慢生长对电催化剂的尺寸有积极影响，对电催化剂的催化性能起着重要作用。在适当浓度的氧化石墨烯的加入下，氧化石墨烯对纳米催化剂具有稳定作用。本文采用微波辅助还原法合成了不同浓度(0.5、1.0、2.0、3.0和4.0 mg mL−1)的还原氧化石墨烯负载钯电催化剂，还原氧化石墨烯与钯的体积和质量比固定。结果表明，在1.0 mg mL−1浓度下合成的还原氧化石墨烯负载钯具有最佳的甲醇氧化反应活性(405.37 mA mg−1)和最大的电化学活性表面积(83.57 m2 g−1)。
{"title":"Nucleation and growth controlled reduced graphene oxide–supported palladium electrocatalysts for methanol oxidation reaction","authors":"J. C. Ng, C. Y. Tan, B. Ong, A. Matsuda, W. Basirun, W. K. Tan, Ramesh Singh, B. Yap","doi":"10.1177/1847980419827171","DOIUrl":"https://doi.org/10.1177/1847980419827171","url":null,"abstract":"In spite of advantages of direct methanol fuel cells, low methanol oxidation reaction and fuel crossover from anode to cathode, there remains a challenge that inhibits it from being commercialized. Active electrocatalysts are in high demand to promote the methanol oxidation reaction. The methanol reached at the anode can be immediately reacted, and thus, less methanol to cross to the cathode. The performance of electrocatalysts can be significantly influenced by varying the concentration of precursor solution. Theoretically, concentrated precursor solution facilitates rapid nucleation and growth; diluted precursor solution causes slow nucleation and growth. Rapid nucleation and slow growth have positive effect on the size of electrocatalysts which plays a significant role in the catalytic performance. Upon the addition of appropriate concentration of graphene oxide, the graphene oxide was reported to have stabilizing effect towards the catalyst nanoparticles. This work synthesized reduced graphene oxide–supported palladium electrocatalysts at different concentrations (0.5, 1.0, 2.0, 3.0 and 4.0 mg mL−1) with fixed volume and mass ratio of reduced graphene oxide to palladium by microwave-assisted reduction method. Results showed that reduced graphene oxide–supported palladium synthesized at a concentration of 1.0 mg mL−1 gave the best methanol oxidation reactivity (405.37 mA mg−1) and largest electrochemical active surface area (83.57 m2 g−1).","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":"9 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980419827171","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"65714611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-25DOI: 10.1177/1847980418824813
H. Kwon, H. Chalabi, A. Alú
Ways to achieve highly efficient electromagnetic absorption over a broad bandwidth and broad angular spectrum have been discussed extensively in the past decades for various applications, such as low reflection devices and energy harvesting. To satisfy the efficiency requirements, metamaterial approaches have been explored in recent years. In this context, most studies have suggested the use of frequency selective surfaces or arrays of plasmonic resonators, which limit bandwidth and angular spectrum of performance. Here, we explore the application of refractory Brewster metasurfaces for photovoltaic applications. By matching the surface impedance of metasurfaces and free space at the Brewster angle, we show that metasurfaces can lead to efficient light absorption, and their response can be controlled accurately both in the angular and in the frequency spectrum to match the requirements of energy harvesting systems and facilitate large efficiency, high-temperature energy harvesting.
{"title":"Refractory Brewster metasurfaces control the frequency and angular spectrum of light absorption","authors":"H. Kwon, H. Chalabi, A. Alú","doi":"10.1177/1847980418824813","DOIUrl":"https://doi.org/10.1177/1847980418824813","url":null,"abstract":"Ways to achieve highly efficient electromagnetic absorption over a broad bandwidth and broad angular spectrum have been discussed extensively in the past decades for various applications, such as low reflection devices and energy harvesting. To satisfy the efficiency requirements, metamaterial approaches have been explored in recent years. In this context, most studies have suggested the use of frequency selective surfaces or arrays of plasmonic resonators, which limit bandwidth and angular spectrum of performance. Here, we explore the application of refractory Brewster metasurfaces for photovoltaic applications. By matching the surface impedance of metasurfaces and free space at the Brewster angle, we show that metasurfaces can lead to efficient light absorption, and their response can be controlled accurately both in the angular and in the frequency spectrum to match the requirements of energy harvesting systems and facilitate large efficiency, high-temperature energy harvesting.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980418824813","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48476368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-24DOI: 10.1177/1847980418825034
Yi Wang, Mi Zhang, Xiaolan Song, Hao Huang, Feng-sheng Li
Nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanocomposites, in which 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanoparticles uniformly embedded in nitrocellulose/glycidyl azide polymer matrix, were synthesized using a sol–gel supercritical method. The micron morphology, crystal phase, molecular structure, specific surface area, and surface elements were characterized using scanning electron microscopy, X-ray diffractometry, infrared, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy analyses, respectively. Thermal analyses were performed, and the kinetic and thermodynamic parameters, such as activation energy, per-exponent factor, rate constant, activation heat, activation free energy, and activation entropy, were calculated. The decomposition products of the nitrocellulose/glycidyl azide polymer matrix and nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane were also investigated by differential scanning calorimetry–infrared analysis. The result indicated that the main decomposition product of nitrocellulose/glycidyl azide polymer is carbon dioxide and the –N3 group in glycidyl azide polymer decomposed to nitrogen without being detected by infrared spectrometer; the main decomposition products of nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane are carbon dioxide, nitrous oxide, and water, and few carbon monoxide, methane, and nitrogen oxide are also detected. Energy performances of nitrocellulose/glycidyl azide polymer matrix and nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanocomposites were evaluated, that is, the parameters such as standard specific impulse, characteristic speed, combustion chamber temperature, average molecular weight of combustion products, and explosion heat were calculated. The results illustrated that as the weight percentage of nitrocellulose increases, the values of standard specific impulse, characteristic speed, average molecular weight of combustion products, combustion chamber temperature, and explosion heat increase. This was ascribed to that the oxygen balance of glycidyl azide polymer is substantially lower than that of nitrocellulose, which results in that the chemical energy of glycidyl azide polymer does not release sufficiently. Additionally, as weight percentage of glycidyl azide polymer increases, the impact and friction sensitivity of the composites decrease obviously. This means that glycidyl azide polymer is much more insensitive than nitrocellulose.
{"title":"Characteristics and properties of nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanocomposites synthesized using a sol–gel supercritical method","authors":"Yi Wang, Mi Zhang, Xiaolan Song, Hao Huang, Feng-sheng Li","doi":"10.1177/1847980418825034","DOIUrl":"https://doi.org/10.1177/1847980418825034","url":null,"abstract":"Nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanocomposites, in which 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanoparticles uniformly embedded in nitrocellulose/glycidyl azide polymer matrix, were synthesized using a sol–gel supercritical method. The micron morphology, crystal phase, molecular structure, specific surface area, and surface elements were characterized using scanning electron microscopy, X-ray diffractometry, infrared, Brunauer–Emmett–Teller, and X-ray photoelectron spectroscopy analyses, respectively. Thermal analyses were performed, and the kinetic and thermodynamic parameters, such as activation energy, per-exponent factor, rate constant, activation heat, activation free energy, and activation entropy, were calculated. The decomposition products of the nitrocellulose/glycidyl azide polymer matrix and nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane were also investigated by differential scanning calorimetry–infrared analysis. The result indicated that the main decomposition product of nitrocellulose/glycidyl azide polymer is carbon dioxide and the –N3 group in glycidyl azide polymer decomposed to nitrogen without being detected by infrared spectrometer; the main decomposition products of nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane are carbon dioxide, nitrous oxide, and water, and few carbon monoxide, methane, and nitrogen oxide are also detected. Energy performances of nitrocellulose/glycidyl azide polymer matrix and nitrocellulose/glycidyl azide polymer/2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane nanocomposites were evaluated, that is, the parameters such as standard specific impulse, characteristic speed, combustion chamber temperature, average molecular weight of combustion products, and explosion heat were calculated. The results illustrated that as the weight percentage of nitrocellulose increases, the values of standard specific impulse, characteristic speed, average molecular weight of combustion products, combustion chamber temperature, and explosion heat increase. This was ascribed to that the oxygen balance of glycidyl azide polymer is substantially lower than that of nitrocellulose, which results in that the chemical energy of glycidyl azide polymer does not release sufficiently. Additionally, as weight percentage of glycidyl azide polymer increases, the impact and friction sensitivity of the composites decrease obviously. This means that glycidyl azide polymer is much more insensitive than nitrocellulose.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980418825034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44660990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-17DOI: 10.1177/1847980418824470
J. Michael, Qifeng Zhang, Danling Wang
MXenes have been under a lot of scientific investigation due to the novel characteristics that are inherent to two-dimensional nanostructures. There are a multitude of MXenes being studied and one of the most popular among these would be the titanium carbides. The general formula for titanium carbide is Ti n + 1C n for the nanosheets produced that have undergone much study in the past few years. These studies include how the etching process affects the final MXene sheet and how the post-processing via heat or combining with polymers and/or inorganic compounds influences the mechanical and electrical properties. It is found that different etching techniques can be used to change the electrical properties of the produced MXenes and different post-processing techniques can be used to further change the properties of the nanosheets. The possible application of the titanium carbide MXenes as chemical sensing and energy storage materials will be briefly discussed. MXene nanosheets show promise in such devices due to their high surface area to volume ratio and their specific surface structure with feasible surface functionalization.
由于二维纳米结构固有的新特性，MXenes已经受到了大量的科学研究。有许多MXenes正在被研究，其中最受欢迎的是碳化钛。碳化钛的一般分子式是Ti n + 1C n，这是近年来研究较多的纳米片。这些研究包括蚀刻过程如何影响最终的MXene片材，以及通过加热或与聚合物和/或无机化合物结合的后处理如何影响机械和电气性能。研究发现，不同的蚀刻技术可以改变制备的MXenes的电学性质，不同的后处理技术可以进一步改变纳米片的性质。简要讨论了碳化钛MXenes作为化学传感和储能材料的应用前景。MXene纳米片由于其高表面积体积比和具有可行表面功能化的特定表面结构而在此类器件中显示出前景。
{"title":"Titanium carbide MXene: Synthesis, electrical and optical properties and their applications in sensors and energy storage devices","authors":"J. Michael, Qifeng Zhang, Danling Wang","doi":"10.1177/1847980418824470","DOIUrl":"https://doi.org/10.1177/1847980418824470","url":null,"abstract":"MXenes have been under a lot of scientific investigation due to the novel characteristics that are inherent to two-dimensional nanostructures. There are a multitude of MXenes being studied and one of the most popular among these would be the titanium carbides. The general formula for titanium carbide is Ti n + 1C n for the nanosheets produced that have undergone much study in the past few years. These studies include how the etching process affects the final MXene sheet and how the post-processing via heat or combining with polymers and/or inorganic compounds influences the mechanical and electrical properties. It is found that different etching techniques can be used to change the electrical properties of the produced MXenes and different post-processing techniques can be used to further change the properties of the nanosheets. The possible application of the titanium carbide MXenes as chemical sensing and energy storage materials will be briefly discussed. MXene nanosheets show promise in such devices due to their high surface area to volume ratio and their specific surface structure with feasible surface functionalization.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980418824470","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47785605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-07DOI: 10.1177/1847980418821037
Srosh Fazil, M. Bangesh, W. Rehman, Khurram Liaqat, Shaukat Saeed, M. Sajid, M. Waseem, M. Shakeel, I. Bibi, Cun‐Yue Guo
Ethyltriethoxysilane-functionalized graphene oxide/polyimide composite films were synthesized. Eighty percent improvement in Young’s modulus, high thermal stability at 800°C, and 3.46-fold increase in dielectric constants compared to polyimide with a dielectric loss of only 0.035 were exhibited by these composite films.
{"title":"Mechanical, thermal, and dielectric properties of functionalized graphene oxide/polyimide nanocomposite films","authors":"Srosh Fazil, M. Bangesh, W. Rehman, Khurram Liaqat, Shaukat Saeed, M. Sajid, M. Waseem, M. Shakeel, I. Bibi, Cun‐Yue Guo","doi":"10.1177/1847980418821037","DOIUrl":"https://doi.org/10.1177/1847980418821037","url":null,"abstract":"Ethyltriethoxysilane-functionalized graphene oxide/polyimide composite films were synthesized. Eighty percent improvement in Young’s modulus, high thermal stability at 800°C, and 3.46-fold increase in dielectric constants compared to polyimide with a dielectric loss of only 0.035 were exhibited by these composite films.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980418821037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45329336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1177/1847980419851409
B. Wansink
It has come to our attention that the article “Peak-end pizza: prices delay evaluations of quality” by David R Just, Ozge Sigirci and Brian Wansink published in Journal of Product & Brand Management, Vol. 24 Issue: 7, pp. 770-778 contains errors in the data presented and does not fully attribute one of the sources drawn upon. In response to recent criticism of the original work and in addition to institutional reanalysis, the authors have sought the independent feedback of a researcher at Mathematica Policy Research who has in turn reviewed the text, tables and Stata output contained in this correction for consistency. Mathematica was compensated for this work. These analyses focused on pizza; therefore, diners who did not report eating at least one piece of pizza were not included in the analyses. Consistent with the original manuscript, two additional diners were eliminated from this analysis because one person’s height was noted as 8 inches and another one’s weight was noted as 450 lbs. Table I originally reported the number of observations for each column erroneously as n 62, n 60 and n 122 for the US$4 buffet, US$8 buffet and all treatments, respectively. In fact, the number of observations varies by question due to respondents skipping questions. The corrected table, below, lists the number of observations for each cell. In addition, there are two other slight changes due to rounding errors (all changes appear in bold type). The online version of Table I has been corrected to attribute the original source “Lower Buffet Prices Lead to Less Taste Satisfaction” published in Journal of Sensory Studies, 2014, 29, 5. In conducting this updated analysis, the authors opted to use Stata 14.0 for convenient scripting and log file generation and to use a Hotelling’s test of differences in ratings rather than the F-test reported in the article. The article reports F-tests for differences in average ratings of first, middle and last slice, respectively, of 16.56 (p 0.00) and 0.65 (p 0.53) for the US$4 and US$8 conditions, respectively. The Hotelling’s test produces F-statistics of 10.44 (p 0.01) and 0.98 (p 0.39), respectively. Minor differences in rounding were found in Tables II and III. Note that in Table III, different numbers of observations are used for each line due to differential response rates to survey questions. A full script and log file can be found here: https://doi.org/10.6077/J5CISER2783 These errors have been corrected in the online version. The authors apologize sincerely for these errors.
{"title":"Corrigendum","authors":"B. Wansink","doi":"10.1177/1847980419851409","DOIUrl":"https://doi.org/10.1177/1847980419851409","url":null,"abstract":"It has come to our attention that the article “Peak-end pizza: prices delay evaluations of quality” by David R Just, Ozge Sigirci and Brian Wansink published in Journal of Product & Brand Management, Vol. 24 Issue: 7, pp. 770-778 contains errors in the data presented and does not fully attribute one of the sources drawn upon. In response to recent criticism of the original work and in addition to institutional reanalysis, the authors have sought the independent feedback of a researcher at Mathematica Policy Research who has in turn reviewed the text, tables and Stata output contained in this correction for consistency. Mathematica was compensated for this work. These analyses focused on pizza; therefore, diners who did not report eating at least one piece of pizza were not included in the analyses. Consistent with the original manuscript, two additional diners were eliminated from this analysis because one person’s height was noted as 8 inches and another one’s weight was noted as 450 lbs. Table I originally reported the number of observations for each column erroneously as n 62, n 60 and n 122 for the US$4 buffet, US$8 buffet and all treatments, respectively. In fact, the number of observations varies by question due to respondents skipping questions. The corrected table, below, lists the number of observations for each cell. In addition, there are two other slight changes due to rounding errors (all changes appear in bold type). The online version of Table I has been corrected to attribute the original source “Lower Buffet Prices Lead to Less Taste Satisfaction” published in Journal of Sensory Studies, 2014, 29, 5. In conducting this updated analysis, the authors opted to use Stata 14.0 for convenient scripting and log file generation and to use a Hotelling’s test of differences in ratings rather than the F-test reported in the article. The article reports F-tests for differences in average ratings of first, middle and last slice, respectively, of 16.56 (p 0.00) and 0.65 (p 0.53) for the US$4 and US$8 conditions, respectively. The Hotelling’s test produces F-statistics of 10.44 (p 0.01) and 0.98 (p 0.39), respectively. Minor differences in rounding were found in Tables II and III. Note that in Table III, different numbers of observations are used for each line due to differential response rates to survey questions. A full script and log file can be found here: https://doi.org/10.6077/J5CISER2783 These errors have been corrected in the online version. The authors apologize sincerely for these errors.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980419851409","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44246616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.1177/1847980418821778
Shimaa E. Rashad, A. Zaki, A. Farghali
The heterogeneous photocatalysis using semiconductor nanocrystals is an important process in the field of water treatment since it is a low cost, environmentally friendly, and zero waste technique. In this work, titanate nanostructures (sheets, tubes, and wires) were prepared by simple hydrothermal method. All samples were characterized by X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, and Zetasizer. The results revealed that tuning the morphology of TiO2 changed the activity of the prepared nanostructures, where titanate nanowires exhibited the highest photocatalytic activity toward crystal violet dye, reaching 100% at pH 3 under ultraviolet illumination for 35 min.
{"title":"Morphological effect of titanate nanostructures on the photocatalytic degradation of crystal violet","authors":"Shimaa E. Rashad, A. Zaki, A. Farghali","doi":"10.1177/1847980418821778","DOIUrl":"https://doi.org/10.1177/1847980418821778","url":null,"abstract":"The heterogeneous photocatalysis using semiconductor nanocrystals is an important process in the field of water treatment since it is a low cost, environmentally friendly, and zero waste technique. In this work, titanate nanostructures (sheets, tubes, and wires) were prepared by simple hydrothermal method. All samples were characterized by X-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, and Zetasizer. The results revealed that tuning the morphology of TiO2 changed the activity of the prepared nanostructures, where titanate nanowires exhibited the highest photocatalytic activity toward crystal violet dye, reaching 100% at pH 3 under ultraviolet illumination for 35 min.","PeriodicalId":19018,"journal":{"name":"Nanomaterials and Nanotechnology","volume":" ","pages":""},"PeriodicalIF":3.7,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1177/1847980418821778","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48753337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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