Pub Date : 2022-01-11DOI: 10.1088/2399-1984/ac4a27
O. Konevtsova, D. Roshal, S. Rochal
Moiré patterns (MPs), arising from the superposition of two lattices with close periods, are tightly related to the physicochemical properties of bilayer nanostructures. Here, we develop the theory of complex MPs emerging in twisted bilayer graphene and planar nets of double-walled nanotubes at significant relative twist and/or deformation of layers. The proposed theory clarifies the physicochemical regularities arising at sorting of single-walled carbon nanotubes (SWCNTs) by organic molecules, which self-assemble in regular coatings on both the tubes and planar graphene. We introduce and consider an outer tubular virtual lattice that is a parent structure for the deposited coating and due to this fact, its existence is crucial for the coating formation. As we show, such outer lattices exist only for successfully sorted SWCNTs and the superposition between the outer lattice and SWCNT forms a specific long-period MP. We explain known experimental results of SWCNT sorting by molecules of flavin group, poly(9,9-dioctylfluorene-2,7-diyl), and poly [(m-phenylenevinylene)-alt-(p-phenylenevinylene)]. Also, our approach points out other organic molecules and polymers suitable for effective carbon nanotube sorting.
{"title":"Moiré patterns and carbon nanotube sorting","authors":"O. Konevtsova, D. Roshal, S. Rochal","doi":"10.1088/2399-1984/ac4a27","DOIUrl":"https://doi.org/10.1088/2399-1984/ac4a27","url":null,"abstract":"Moiré patterns (MPs), arising from the superposition of two lattices with close periods, are tightly related to the physicochemical properties of bilayer nanostructures. Here, we develop the theory of complex MPs emerging in twisted bilayer graphene and planar nets of double-walled nanotubes at significant relative twist and/or deformation of layers. The proposed theory clarifies the physicochemical regularities arising at sorting of single-walled carbon nanotubes (SWCNTs) by organic molecules, which self-assemble in regular coatings on both the tubes and planar graphene. We introduce and consider an outer tubular virtual lattice that is a parent structure for the deposited coating and due to this fact, its existence is crucial for the coating formation. As we show, such outer lattices exist only for successfully sorted SWCNTs and the superposition between the outer lattice and SWCNT forms a specific long-period MP. We explain known experimental results of SWCNT sorting by molecules of flavin group, poly(9,9-dioctylfluorene-2,7-diyl), and poly [(m-phenylenevinylene)-alt-(p-phenylenevinylene)]. Also, our approach points out other organic molecules and polymers suitable for effective carbon nanotube sorting.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2022-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45710646","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-12-17DOI: 10.1088/2399-1984/ac446c
F. A. Jan, Wajidullah, R. Ullah, Salman, N. Ullah, A. Salam
Titanium dioxide (TiO2) and holmium-doped titanium dioxide (Ho-TiO2) nanoparticles(NPs) were synthesized through a sol gel route. The synthesized NPs were characterized by ultraviolet-visible (UV–Vis) spectroscopy, x-ray diffraction (XRD), energy dispersive x-ray analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and photoluminescence (PL) spectroscopy. DNA binding, antibacterial, hemolysis, and antioxidant assays of the synthesized NPs were also carried out in order to find their therapeutic applications. Successful doping of TiO2 with Ho reduced the bandgap from 3.10 to 2.88 eV. SEM and XRD analysis showed that both TiO2 and Ho-TiO2 NPs exhibit a tetragonal structure and the morphology of the particles improved and agglomeration reduced as a result of doping. The PL emission intensity of TiO2 also reduced with doping. The degradation of Safranin O dye over both the catalysts followed first-order kinetics. The calculated activation energy for the photodegradation of the given dye was found to be 51.7 and 35.2 KJ mol−1 for bare TiO2 and Ho-TiO2 NPs, respectively. After 180 min, 84% and 87% dye degradation was observed using pure TiO2 and Ho-TiO2, respectively. A high percent of degradation of the dye was found at a low concentration (20 ppm) and at optimal dosage (0.035 g) of both the catalysts. The rate of Safranin O dye degradation was found to increase with an increase in temperature and pH of the medium. A DNA binding study revealed that Ho-TiO2 NPs are more capable of binding to human DNA. An antibacterial activity study showed that Ho-TiO2 NPs were more efficient against both gram-negative and gram-positive bacterial strains compared to pure TiO2. Hemolysis assay showed that TiO2 and Ho-TiO2 NPs are non-biocompatible. Ho-TiO2 NPs showed higher anti-oxidant activity compared to bare TiO2.
{"title":"An investigation into the environmental and therapeutic applications of holmium-doped titanium dioxide (Ho-TiO2) nanocatalysts: a kinetic and thermodynamic study of the photocatalytic degradation of Safranin O dye","authors":"F. A. Jan, Wajidullah, R. Ullah, Salman, N. Ullah, A. Salam","doi":"10.1088/2399-1984/ac446c","DOIUrl":"https://doi.org/10.1088/2399-1984/ac446c","url":null,"abstract":"Titanium dioxide (TiO2) and holmium-doped titanium dioxide (Ho-TiO2) nanoparticles(NPs) were synthesized through a sol gel route. The synthesized NPs were characterized by ultraviolet-visible (UV–Vis) spectroscopy, x-ray diffraction (XRD), energy dispersive x-ray analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and photoluminescence (PL) spectroscopy. DNA binding, antibacterial, hemolysis, and antioxidant assays of the synthesized NPs were also carried out in order to find their therapeutic applications. Successful doping of TiO2 with Ho reduced the bandgap from 3.10 to 2.88 eV. SEM and XRD analysis showed that both TiO2 and Ho-TiO2 NPs exhibit a tetragonal structure and the morphology of the particles improved and agglomeration reduced as a result of doping. The PL emission intensity of TiO2 also reduced with doping. The degradation of Safranin O dye over both the catalysts followed first-order kinetics. The calculated activation energy for the photodegradation of the given dye was found to be 51.7 and 35.2 KJ mol−1 for bare TiO2 and Ho-TiO2 NPs, respectively. After 180 min, 84% and 87% dye degradation was observed using pure TiO2 and Ho-TiO2, respectively. A high percent of degradation of the dye was found at a low concentration (20 ppm) and at optimal dosage (0.035 g) of both the catalysts. The rate of Safranin O dye degradation was found to increase with an increase in temperature and pH of the medium. A DNA binding study revealed that Ho-TiO2 NPs are more capable of binding to human DNA. An antibacterial activity study showed that Ho-TiO2 NPs were more efficient against both gram-negative and gram-positive bacterial strains compared to pure TiO2. Hemolysis assay showed that TiO2 and Ho-TiO2 NPs are non-biocompatible. Ho-TiO2 NPs showed higher anti-oxidant activity compared to bare TiO2.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47681698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-12-10DOI: 10.1088/2399-1984/ac421c
Huiwen Chen, Yunlong Li, Bo Zhao, Jun Ming, D. Xue
Scintillators are widely used for x-ray detection in various fields, such as medical diagnostics, industrial inspection and homeland security. Nanocrystals (NCs) of metal halide perovskites (MHPs) and their analogues showed great advantages as x-ray scintillators due to their cheap manufacturing, fast decay time, and room temperature scintillation from quantum confinement effect. However, there are still many challenges unsolved for further industrialization. Herein, it is necessary to summarize the progress of scintillators based on NCs of MHPs and their analogues. In the first section, the scintillation mechanism and key parameters are outlined. Then, various NCs of MHPs and their analogues used as scintillators are reviewed. Finally, the challenges and outlook are discussed. It is believed that NCs of MHPs and their analogues are favorable for large-area and flexible x-ray detectors.
{"title":"Nanocrystals of metal halide perovskites and their analogues as scintillators for x-ray detection","authors":"Huiwen Chen, Yunlong Li, Bo Zhao, Jun Ming, D. Xue","doi":"10.1088/2399-1984/ac421c","DOIUrl":"https://doi.org/10.1088/2399-1984/ac421c","url":null,"abstract":"Scintillators are widely used for x-ray detection in various fields, such as medical diagnostics, industrial inspection and homeland security. Nanocrystals (NCs) of metal halide perovskites (MHPs) and their analogues showed great advantages as x-ray scintillators due to their cheap manufacturing, fast decay time, and room temperature scintillation from quantum confinement effect. However, there are still many challenges unsolved for further industrialization. Herein, it is necessary to summarize the progress of scintillators based on NCs of MHPs and their analogues. In the first section, the scintillation mechanism and key parameters are outlined. Then, various NCs of MHPs and their analogues used as scintillators are reviewed. Finally, the challenges and outlook are discussed. It is believed that NCs of MHPs and their analogues are favorable for large-area and flexible x-ray detectors.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49113038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-12-01DOI: 10.1088/2399-1984/ac279b
K. Samrat, M. Chandraprabha, R. Hari Krishna, R. Sharath, B. Harish
Microbial wound infections leading to secondary complications in wound healing has resulted in high demand for therapeutic drugs with improved efficacy. Despite achieving enhanced bio-activity and higher bioavailability compared to its bulk form, nano-sulfur (SNP) has been explored to a very limited extent for wound healing applications. In this work, we prepare biogenic SNP (SNP-B) via simple biogenic technique using pomegranate (Punica granatum) peel extract and demonstrate its antimicrobial and wound healing activity. The SNP-B was characterized using powder x-ray diffractometer, FESEM, transmission electron microscopy and Raman spectroscopy. Different wound models (excision, incision, dead space and burn) were used to assess the wound healing potential of SNP-B. The 2% (w/w) SNP-B treated group exhibited enhanced wound contraction rate (excision wound, 99.62 ± 0.59%; burn wound, 99.46 ± 0.59%), breaking strength (393.2 ± 10.87 g cm−2), and granulation tissue weight (166.8 ± 9.45 mg) compared to the control group (excision wound, 84.24 ± 2.78%; burn wound, 90.58 ± 3.2%; breaking strength, 241.3 ± 16.11 g cm−2; granulation tissue weight, 91.17 ± 7.28 mg). The efficacy of 2% (w/w) SNP-B was comparable to that of standard (5% w/w povidone-iodine ointment) in all the wound models analyzed. The SNP-B showed enhanced antibacterial activity with a MIC value of 90, 80, 80, and 60 μg ml−1 for Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus, respectively. The results obtained prove the potential of SNP-B as a multifunctional therapeutic agent for topical applications.
微生物伤口感染导致伤口愈合中的继发并发症，导致对疗效提高的治疗药物的高需求。尽管与本体形式相比，纳米硫具有更强的生物活性和更高的生物利用度，但其在伤口愈合应用中的探索程度非常有限。在这项工作中，我们使用石榴皮提取物通过简单的生物技术制备了生物SNP（SNP-B），并证明了其抗菌和伤口愈合活性。利用粉末x射线衍射仪、FESEM、透射电子显微镜和拉曼光谱对SNP-B进行了表征。使用不同的伤口模型（切除、切口、死区和烧伤）来评估SNP-B的伤口愈合潜力。2%（w/w）SNP-B治疗组的伤口收缩率（切除伤口，99.62±0.59%；烧伤伤口，99.46±0.59%）、断裂强度（393.2±10.87 g cm−2）、，肉芽组织重量（166.8±9.45 mg）与对照组相比（切除伤口84.24±2.78%；烧伤伤口90.58±3.2%；断裂强度241.3±16.11 g cm−2；肉芽组织质量91.17±7.28 mg）。在所有分析的伤口模型中，2%（w/w）SNP-B的疗效与标准（5%w/w聚维酮碘软膏）相当。SNP-B对铜绿假单胞菌、大肠杆菌、枯草芽孢杆菌和金黄色葡萄球菌的MIC值分别为90、80、80和60μg ml−1，显示出增强的抗菌活性。所获得的结果证明了SNP-B作为局部应用的多功能治疗剂的潜力。
{"title":"Biogenic synthesis of nano-sulfur using Punica granatum fruit peel extract with enhanced antimicrobial activities for accelerating wound healing","authors":"K. Samrat, M. Chandraprabha, R. Hari Krishna, R. Sharath, B. Harish","doi":"10.1088/2399-1984/ac279b","DOIUrl":"https://doi.org/10.1088/2399-1984/ac279b","url":null,"abstract":"Microbial wound infections leading to secondary complications in wound healing has resulted in high demand for therapeutic drugs with improved efficacy. Despite achieving enhanced bio-activity and higher bioavailability compared to its bulk form, nano-sulfur (SNP) has been explored to a very limited extent for wound healing applications. In this work, we prepare biogenic SNP (SNP-B) via simple biogenic technique using pomegranate (Punica granatum) peel extract and demonstrate its antimicrobial and wound healing activity. The SNP-B was characterized using powder x-ray diffractometer, FESEM, transmission electron microscopy and Raman spectroscopy. Different wound models (excision, incision, dead space and burn) were used to assess the wound healing potential of SNP-B. The 2% (w/w) SNP-B treated group exhibited enhanced wound contraction rate (excision wound, 99.62 ± 0.59%; burn wound, 99.46 ± 0.59%), breaking strength (393.2 ± 10.87 g cm−2), and granulation tissue weight (166.8 ± 9.45 mg) compared to the control group (excision wound, 84.24 ± 2.78%; burn wound, 90.58 ± 3.2%; breaking strength, 241.3 ± 16.11 g cm−2; granulation tissue weight, 91.17 ± 7.28 mg). The efficacy of 2% (w/w) SNP-B was comparable to that of standard (5% w/w povidone-iodine ointment) in all the wound models analyzed. The SNP-B showed enhanced antibacterial activity with a MIC value of 90, 80, 80, and 60 μg ml−1 for Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis and Staphylococcus aureus, respectively. The results obtained prove the potential of SNP-B as a multifunctional therapeutic agent for topical applications.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44367413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-12-01DOI: 10.1088/2399-1984/ac421d
K. Murata, S. Yagi, Takashi Kanazawa, S. Tsubomatsu, C. Kirkham, K. Nittoh, D. Bowler, K. Miki
Conventional doping processes are no longer viable for realizing extreme structures, such as a δ-doped layer with multiple elements, such as the heavy Bi, within the silicon crystal. Here, we demonstrate the formation of (Bi + Er)-δ-doped layer based on surface nanostructures, i.e. Bi nanolines, as the dopant source by molecular beam epitaxy. The concentration of both Er and Bi dopants is controlled by adjusting the amount of deposited Er atoms, the growth temperature during Si capping and surfactant techniques. Subsequent post-annealing processing is essential in this doping technique to obtain activated dopants in the δ-doped layer. Electric transport measurement and photoluminescence study revealed that both Bi and Er dopants were activated after post-annealing at moderate temperature.
{"title":"Activation of two dopants, Bi and Er in δ-doped layer in Si crystal","authors":"K. Murata, S. Yagi, Takashi Kanazawa, S. Tsubomatsu, C. Kirkham, K. Nittoh, D. Bowler, K. Miki","doi":"10.1088/2399-1984/ac421d","DOIUrl":"https://doi.org/10.1088/2399-1984/ac421d","url":null,"abstract":"Conventional doping processes are no longer viable for realizing extreme structures, such as a δ-doped layer with multiple elements, such as the heavy Bi, within the silicon crystal. Here, we demonstrate the formation of (Bi + Er)-δ-doped layer based on surface nanostructures, i.e. Bi nanolines, as the dopant source by molecular beam epitaxy. The concentration of both Er and Bi dopants is controlled by adjusting the amount of deposited Er atoms, the growth temperature during Si capping and surfactant techniques. Subsequent post-annealing processing is essential in this doping technique to obtain activated dopants in the δ-doped layer. Electric transport measurement and photoluminescence study revealed that both Bi and Er dopants were activated after post-annealing at moderate temperature.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46133403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-11-30DOI: 10.1088/2399-1984/ac3ec1
X. Lei, Bo Liu, Payam Ahmadian Koudakan, Hongge Pan, Yitai Qian, Gongming Wang
Recently, single-atom catalysts (SACs) have been found to be promising candidates for oxygen electrocatalysis in rechargeable lithium–oxygen batteries (LOBs) owing to their high oxygen electrocatalytic activity and high stability, which originates from their unique coordination environments and electronic properties. As a new type of catalyst for LOBs, the advancements have never been reviewed and discussed comprehensively. Herein, breakthroughs in the design of various types of SACs as cathode catalysts for LOBs are summarized, including Co-based, Ru-based, and other types of SACs. Moreover, considerable emphasis is placed on the correlations between the structural feature of the SAC active sites and the electrocatalytic performance of LOBs. Finally, an overview and challenges of SACs for practical LOBs are also provided. This review provides an intensive understanding of SACs for designing efficient oxygen electrocatalysis and offers useful guidelines for the development of SACs in the field of LOBs.
{"title":"Single-atom catalyst cathodes for lithium–oxygen batteries: a review","authors":"X. Lei, Bo Liu, Payam Ahmadian Koudakan, Hongge Pan, Yitai Qian, Gongming Wang","doi":"10.1088/2399-1984/ac3ec1","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ec1","url":null,"abstract":"Recently, single-atom catalysts (SACs) have been found to be promising candidates for oxygen electrocatalysis in rechargeable lithium–oxygen batteries (LOBs) owing to their high oxygen electrocatalytic activity and high stability, which originates from their unique coordination environments and electronic properties. As a new type of catalyst for LOBs, the advancements have never been reviewed and discussed comprehensively. Herein, breakthroughs in the design of various types of SACs as cathode catalysts for LOBs are summarized, including Co-based, Ru-based, and other types of SACs. Moreover, considerable emphasis is placed on the correlations between the structural feature of the SAC active sites and the electrocatalytic performance of LOBs. Finally, an overview and challenges of SACs for practical LOBs are also provided. This review provides an intensive understanding of SACs for designing efficient oxygen electrocatalysis and offers useful guidelines for the development of SACs in the field of LOBs.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46627499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-11-25DOI: 10.1088/2399-1984/ac3d6e
Molood Barmala, M. Behnood
In this work we present the preparation of novel ternary metal oxide nanoparticles, La2Cu0.8Zn0.2O4 (LCZO), using a simple co-precipitation method. The crystalline structure, morphology and composition of the prepared LCZO nanoparticles were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray analysis. The diffuse reflectance spectrum investigation showed that LCZO nanoparticles have considerable light absorption in the visible light region. Also, the LCZO nanoparticles possess a band-gap energy of 2.82 eV. To investigate the visible light photocatalytic potential of the prepared LCZO nanoparticles, two photocatalytic reactions were conducted, namely degradation of methylene blue (MB) solution and desulfurization of dibenzothiophene (DBT). In the presence of a 3:1 molar ratio of H2O2/DBT, a high photocatalytic desulfurization rate of DBT (93.7%) was obtained over 0.2 g of LCZO photocatalyst. In addition, the photocatalytic degradation rate of MB solution was 91.4%. The mechanisms of both photocatalytic reactions were studied using different radical scavenging agents, which showed that hydroxyl radicals are responsible for highly efficient desulfurization and degradation reactions. Moreover, reusability experiments reveal that the prepared LCZO photocatalyst has great stability and recyclability for both desulfurization of DBT and degradation of MB after six reaction cycles.
本文采用简单共沉淀法制备了新型三元金属氧化物纳米粒子la2cu0.8 zn0.2 2o4 (LCZO)。采用x射线衍射、扫描电镜和能量色散x射线分析对制备的LCZO纳米颗粒的晶体结构、形貌和组成进行了表征。漫反射光谱研究表明，LCZO纳米颗粒在可见光区有相当大的光吸收。此外，LCZO纳米颗粒具有2.82 eV的带隙能量。为了考察所制备的LCZO纳米颗粒的可见光催化性能，进行了亚甲基蓝(MB)溶液降解和二苯并噻吩(DBT)脱硫两种光催化反应。在H2O2/DBT摩尔比为3:1的条件下，0.2 g LCZO光催化剂对DBT的光催化脱硫率高达93.7%。此外，光催化对MB溶液的降解率为91.4%。用不同的自由基清除剂对两种光催化反应的机理进行了研究，结果表明，羟基自由基具有高效的脱硫和降解反应。重复使用实验表明，制备的LCZO光催化剂经过6个反应循环后，对DBT的脱硫和MB的降解均具有良好的稳定性和可回收性。
{"title":"Novel ternary metal oxide nanoparticles (La2Cu0.8Zn0.2O4) as a potential photocatalyst for visible light photocatalytic degradation of methylene blue and desulfurization of dibenzothiophene","authors":"Molood Barmala, M. Behnood","doi":"10.1088/2399-1984/ac3d6e","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3d6e","url":null,"abstract":"In this work we present the preparation of novel ternary metal oxide nanoparticles, La2Cu0.8Zn0.2O4 (LCZO), using a simple co-precipitation method. The crystalline structure, morphology and composition of the prepared LCZO nanoparticles were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray analysis. The diffuse reflectance spectrum investigation showed that LCZO nanoparticles have considerable light absorption in the visible light region. Also, the LCZO nanoparticles possess a band-gap energy of 2.82 eV. To investigate the visible light photocatalytic potential of the prepared LCZO nanoparticles, two photocatalytic reactions were conducted, namely degradation of methylene blue (MB) solution and desulfurization of dibenzothiophene (DBT). In the presence of a 3:1 molar ratio of H2O2/DBT, a high photocatalytic desulfurization rate of DBT (93.7%) was obtained over 0.2 g of LCZO photocatalyst. In addition, the photocatalytic degradation rate of MB solution was 91.4%. The mechanisms of both photocatalytic reactions were studied using different radical scavenging agents, which showed that hydroxyl radicals are responsible for highly efficient desulfurization and degradation reactions. Moreover, reusability experiments reveal that the prepared LCZO photocatalyst has great stability and recyclability for both desulfurization of DBT and degradation of MB after six reaction cycles.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46645511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-11-24DOI: 10.1088/2399-1984/ac3ccd
Xin Kuang, Bifeng Yin, Xiping Yang, H. Jia, Bo Xu
The aim of this paper is to evaluate and compare the tribological properties of lubricating oil blends with added nano graphene and nano cerium oxide (CeO2) on the key friction pairs of diesel engines. Dispersion stability is the premise of the study of tribological properties. In this paper, nano CeO2 particles were self-made and high-quality nano graphene was purchased. The dispersion stability of the two nanomaterials in lubricating oil was studied after the same modification. According to the working conditions of the cylinder liner and piston ring, friction and wear tests of the lubricating oil blends containing the modified nanomaterials were carried out at different temperatures. The results showed that both nanomaterials were successfully modified with oleic acid and stearic acid. The dispersion stability of the modified nanomaterials in lubricating oil was improved. The dispersion stability of the lubricating oil blends with graphene before and after modification was slightly higher than that of lubricating oil blends with CeO2 before and after modification. At high temperature, the anti-friction properties of the two nano lubricating oil blends were similar. At ambient temperature, lubricating oil blends containing modified CeO2 did not play a role in reducing friction, while lubricating oil blends with modified graphene had the effect of reducing friction. Whether at ambient temperature or high temperature, the anti-wear property when lubricated with lubricating oil blends with modified CeO2 within the right concentration range was better than that when lubricated with lubricating oil blends containing modified graphene.
{"title":"Study of the tribological properties of nano lubricating oil blends for diesel engines","authors":"Xin Kuang, Bifeng Yin, Xiping Yang, H. Jia, Bo Xu","doi":"10.1088/2399-1984/ac3ccd","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ccd","url":null,"abstract":"The aim of this paper is to evaluate and compare the tribological properties of lubricating oil blends with added nano graphene and nano cerium oxide (CeO2) on the key friction pairs of diesel engines. Dispersion stability is the premise of the study of tribological properties. In this paper, nano CeO2 particles were self-made and high-quality nano graphene was purchased. The dispersion stability of the two nanomaterials in lubricating oil was studied after the same modification. According to the working conditions of the cylinder liner and piston ring, friction and wear tests of the lubricating oil blends containing the modified nanomaterials were carried out at different temperatures. The results showed that both nanomaterials were successfully modified with oleic acid and stearic acid. The dispersion stability of the modified nanomaterials in lubricating oil was improved. The dispersion stability of the lubricating oil blends with graphene before and after modification was slightly higher than that of lubricating oil blends with CeO2 before and after modification. At high temperature, the anti-friction properties of the two nano lubricating oil blends were similar. At ambient temperature, lubricating oil blends containing modified CeO2 did not play a role in reducing friction, while lubricating oil blends with modified graphene had the effect of reducing friction. Whether at ambient temperature or high temperature, the anti-wear property when lubricated with lubricating oil blends with modified CeO2 within the right concentration range was better than that when lubricated with lubricating oil blends containing modified graphene.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43311682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-11-24DOI: 10.1088/2399-1984/ac3ccc
G. Zeevi, Joanna Dehnel, Adam K. Budniak, Y. Milyutin, G. Ankonina, H. Haick, E. Lifshitz, Y. Yaish
The integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate various CdSe/CdS core/shell NCs, such as seeded quantum dots and asymmetric seeded nanorods (a-sNRs), with a single-wall CNT in a field-effect transistor geometry. We used electrical measurements to probe a light-induced charge transfer (LICT) between the CdSe/CdS NCs and the CNT. We investigate the effect of gate voltage on the LICT magnitude and temporal characteristics. Surprisingly, the measured photo-response depends on the gate voltage, and we observe both electrons and holes transfer from the a-sNRs to the CNT. Furthermore, a comparison between LICT measurements on different devices with different CNTs and NC types reveals that the charge transfer time is directly proportional to the shell-thickness around the CdSe core and inversely correlated with the NCs size. The recovery of the charge trapped inside the CdSe/CdS NCs is characterized by two distinct fast and slow relaxation times, which depend on the NCs size and CNT type. Although, the charge relaxation time is similar between the symmetric QDs and the asymmetric sNRs, the overall percentage of the remaining charge in the QDs is significantly larger than in the sNRs. Understanding both gate voltage and NCs size effect on the LICT processes can optimize the performance of optoelectronic devices.
{"title":"Dynamics of light-induced charge transfer between carbon nanotube and CdSe/CdS core/shell nanocrystals","authors":"G. Zeevi, Joanna Dehnel, Adam K. Budniak, Y. Milyutin, G. Ankonina, H. Haick, E. Lifshitz, Y. Yaish","doi":"10.1088/2399-1984/ac3ccc","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3ccc","url":null,"abstract":"The integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate various CdSe/CdS core/shell NCs, such as seeded quantum dots and asymmetric seeded nanorods (a-sNRs), with a single-wall CNT in a field-effect transistor geometry. We used electrical measurements to probe a light-induced charge transfer (LICT) between the CdSe/CdS NCs and the CNT. We investigate the effect of gate voltage on the LICT magnitude and temporal characteristics. Surprisingly, the measured photo-response depends on the gate voltage, and we observe both electrons and holes transfer from the a-sNRs to the CNT. Furthermore, a comparison between LICT measurements on different devices with different CNTs and NC types reveals that the charge transfer time is directly proportional to the shell-thickness around the CdSe core and inversely correlated with the NCs size. The recovery of the charge trapped inside the CdSe/CdS NCs is characterized by two distinct fast and slow relaxation times, which depend on the NCs size and CNT type. Although, the charge relaxation time is similar between the symmetric QDs and the asymmetric sNRs, the overall percentage of the remaining charge in the QDs is significantly larger than in the sNRs. Understanding both gate voltage and NCs size effect on the LICT processes can optimize the performance of optoelectronic devices.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47890798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 : 2021-11-23DOI: 10.1088/2399-1984/ac3c8f
Bowen Zheng, Zeyu Zheng, Grace X. Gu
Graphene aerogels (GAs), a special class of 3D graphene assemblies, are well known for their exceptional combination of high strength, lightweightness, and high porosity. However, due to microstructural randomness, the mechanical properties of GAs are also highly stochastic, an issue that has been observed but insufficiently addressed. In this work, we develop Gaussian process metamodels to not only predict important mechanical properties of GAs but also quantify their uncertainties. Using the molecular dynamics simulation technique, GAs are assembled from randomly distributed graphene flakes and spherical inclusions, and are subsequently subject to a quasi-static uniaxial tensile load to deduce mechanical properties. Results show that given the same density, mechanical properties such as the Young’s modulus and the ultimate tensile strength can vary substantially. Treating density, Young’s modulus, and ultimate tensile strength as functions of the inclusion size, and using the simulated GA results as training data, we build Gaussian process metamodels that can efficiently predict the properties of unseen GAs. In addition, statistically valid confidence intervals centered around the predictions are established. This metamodel approach is particularly beneficial when the data acquisition requires expensive experiments or computation, which is the case for GA simulations. The present research quantifies the uncertain mechanical properties of GAs, which may shed light on the statistical analysis of novel nanomaterials of a broad variety.
{"title":"Uncertainty quantification and prediction for mechanical properties of graphene aerogels via Gaussian process metamodels","authors":"Bowen Zheng, Zeyu Zheng, Grace X. Gu","doi":"10.1088/2399-1984/ac3c8f","DOIUrl":"https://doi.org/10.1088/2399-1984/ac3c8f","url":null,"abstract":"Graphene aerogels (GAs), a special class of 3D graphene assemblies, are well known for their exceptional combination of high strength, lightweightness, and high porosity. However, due to microstructural randomness, the mechanical properties of GAs are also highly stochastic, an issue that has been observed but insufficiently addressed. In this work, we develop Gaussian process metamodels to not only predict important mechanical properties of GAs but also quantify their uncertainties. Using the molecular dynamics simulation technique, GAs are assembled from randomly distributed graphene flakes and spherical inclusions, and are subsequently subject to a quasi-static uniaxial tensile load to deduce mechanical properties. Results show that given the same density, mechanical properties such as the Young’s modulus and the ultimate tensile strength can vary substantially. Treating density, Young’s modulus, and ultimate tensile strength as functions of the inclusion size, and using the simulated GA results as training data, we build Gaussian process metamodels that can efficiently predict the properties of unseen GAs. In addition, statistically valid confidence intervals centered around the predictions are established. This metamodel approach is particularly beneficial when the data acquisition requires expensive experiments or computation, which is the case for GA simulations. The present research quantifies the uncertain mechanical properties of GAs, which may shed light on the statistical analysis of novel nanomaterials of a broad variety.","PeriodicalId":54222,"journal":{"name":"Nano Futures","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2021-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46786747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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