Nanotechnology Research Research Articles

Utilization of Nanotechnology and Nanomaterials in Biodiesel Production and Property Enhancement

In today’s world, the applications of nanotechnology and nanomaterials are attracting interest in a wide variety of study domains because of their appealing qualities. The use of nanotechnology and nanomaterials in biodiesel processing and manufacturing is a focus of research globally. For accelerating the progress and development of biodiesel production, more focus is being given to the application of advanced nanotechnology for maximum yield in low cost. Hence, this paper will discuss the utilization of numerous nanomaterials/nanocatalysts for biodiesel synthesis from multiple feedstocks. This study will also focus on nanomaterials’ applications in algae cultivation and lipid extraction. Furthermore, the current study will comprehensively overview the nanoadditives blended biodiesel in diesel engines and the significant challenges and future opportunities. Moreover, this paper will also focus on human and environmental safety concerns of nanotechnology-based large-scale biodiesel production. Hence, this review will provide perception for future manufacturers, researchers, and academicians into the extent of research in nanotechnology and nanomaterials assisted biodiesel production and its efficiency enhancement.

Green Synthesis of Cobalt Ferrite Nanoparticles: An Emerging Material for Environmental and Biomedical Applications

Research and utilization of nanotechnology are growing exponentially in every aspect of life. The constant growth of applications for magnetic nanoparticles, specifically nanoferrites, attracted many researchers. Among them, nanocobalt ferrite is the most crucial and studied magnetic nanoparticle. Environmentally benign synthetic methods became necessary to minimize environmental and occupational hazards. Green synthesis approaches in science and technology are now widely applied in the synthesis of nanomaterials. Herein, we reviewed recent advances in synthesizing nanocobalt ferrites and their composites using various scientific search engines. Subsequently, various applications were discussed, such as environmental (treatment of water/wastewater, photocatalytic degradation of dyes, and nanosorbent for environmental remediation) and biomedical (nanobiosensors for cancer diagnosis at the primary stage, effective targeted drug delivery, magnetic resonance imaging, hyperthermia, and potential drug candidates against cancer and microbial infections). This review offers comprehensive knowledge on how to choose appropriate natural resources for the green synthesis of nanocobalt ferrite and the benefits of this approach compared to conventional methods.

A Perspective Review on the Current Status and Development of Polymer Flooding in Enhanced Oil Recovery Using Polymeric Nanofluids

The globally increasing demand for crude oil has prompted the oil industry to enhance oil production from primary, secondary, and tertiary recovery methods to fulfill the global requirement. Therefore, enhanced oil recovery (EOR) is expected to increase its importance in the coming years. Because of limited efficiency, applicability, and higher gas and thermal injection costs, chemical EOR processes have been considered as an alternative in some special cases. Chemical EOR processes are accepted widely because of their higher efficiency, economic and technical feasibility, and optimum capital cost. Therefore, research of novel chemical compounds is immense in the oil industry. Research of nanotechnology in the petroleum industry has attracted attention among all novel chemical compounds in the past few years. This work focuses on the review of previous research regarding the current scenario of polymer flooding, challenges of polymer flooding, polymeric nanofluid in EOR, recent developments in polymer flooding, characteristics of polymeric nanofluids, prospects, and economic feasibility for polymeric nanofluids’ applications in EOR. This paper also reviews the characterization of polymeric nanofluids such as rheology, stability, wettability alteration, interfacial tension reduction, and absorption control. It has been found from a literature review that polymeric nanofluids are more effective in oil recovery considering viscosity modification, stability enhancement, and chemical adsorption control. Oil recovery can be additionally increased by up to 10–15% original-oil-in-place applying polymeric nanofluids.

A Novel Construct of Coral Granules-Poly-L-Lactic Acid Nanomembrane Sandwich Double Stem Cell Sheet Transplantation as Regenerative Therapy of Bone Defect Model

We examined the use of a new approach in nanotechnology and stem cell research as regenerative therapy for bone tissue defects. We compared in vitro osteogenic potential of human Wharton jelly mesenchymal stem cells using coral granules and poly-L-lactic acid nanofiber according to proliferation (by cck-8 kit) and osteogenes (runt-related transcription factor 2, alkaline phosphatase, osteonectin) by quantitative reverse transcription-polymerase chain reaction, alkaline phosphatase assay, calcium measurement, and assessment of mineralization by Alizarin red and von Kossa staining. To overcome the limitations of natural coral, we made a modification by packaging the coral granules-human Wharton jelly mesenchymal stem cells by nanomembrane-human Wharton jelly mesenchymal stem cells to form sandwich double cell sheets and compared this hole with other holes (one was filled by human Wharton jelly mesenchymal stem cell suspension, and the other was filled by coral granules saturated with preinduced mesenchymal stem cells) by radiological and histopathological studies for repairing the bone gap. Collagen-coated poly-L-lactic acid showed higher mRNA levels for all osteogenes (P < .001), higher alkaline phosphatase and calcium content (P < .001), and greater stainability. Our in vivo experiment showed that the holes implanted with sandwich double cell sheet-poly-L-lactic acid coral were completely filled mature compact bone. The holes implanted with human Wharton jelly mesenchymal stem cells alone were filled with immature compact bone. Holes implanted with coral granules-human Wharton jelly mesenchymal stem cells were filled with condensed connective tissue. Poly-L-lactic acid nanofiber has greater osteogenic differentiating effect than the coral granules. The new approach of sDCS-PLLA-coral construct proved success for bone regeneration and repairing the bone gap and this may improve the design of tissue constructs for bone tissue regenerative therapy.

Keynotes from Nanotechnology Conference [Theme: Keynotes from Nanotechnology Conference

Prof. Chao-Sung Lai is an Asso­ciate Editor-in-Chief in charge of the Highlights Section. One article is featured in the Highlights Section, entitled “A Conversation about Quantum Literacy, The Chinese Classics and STEAM-based Education at University.” Four papers are featured in this Issue. We invited Keynote/Plenary Speakers from the “2022 IEEE Nanotechnology Conference” to contribute to the papers. The first paper is entitled “Advanced Impacts of Nanotechnology and Intelligence” by Professor Chao-Sung Lai and the research team at Chang Gung University in Taiwan. The second paper is entitled “From Green Electronics to Gray Matter and Cyborg Cells” by Professor Deblina Sarkar at Massachusetts Institute of Technology. The third paper is entitled “There is Plenty of Room All-Around: Highlight of Semiconductor Nanotechnology Research in My Lab” by Prof. Xiuling Li at University of Texas, Austin. The fourth paper is entitled “Nano-MOSFET – Foundation of Quantum Computing, Part I: Qubits, Quantum Architecture and Control, Cryo-CMOS” by Xiao Xue, Pascal ‘t Hart, Edoardo Charbon, Fabio Sebastiano, Andrei Vladimirescu.

Multiple Stepwise Synthetic Pathways toward Complex Plasmonic 2D and 3D Nanoframes for Generation of Electromagnetic Hot Zones in a Single Entity

ConspectusRational design of nanocrystals with high controllability via wet chemistry is of critical importance in all areas of nanoscience and nanotechnology research. Specifically, morphologically complex plasmonic nanoparticles have received considerable attention because light-matter interactions are strongly associated with the size and shape of nanoparticles. Among many types of nanostructures, plasmonic nanoframes (NFs) with controllable structural intricacy could be excellent candidates as strong light-entrappers with inner voids as well as high surface area, leading to highly effective interaction with light and analytes compared to their solid counterparts. However, so far studies on single-rim-based NFs have suffered from insufficient near-field focusing capability due to their structural simplicity (e.g., a single rim or NF molded from simple platonic solids), which necessitates a conceptually new NF architecture. If one considers a stereoscopic nanostructure with dual, triple, and multiple resonant intra-nanogaps on each crystallographic facet of nanocrystals, unprecedented physicochemical properties could be expected. Realizing such complex multiple NFs with intraparticle surface plasmon coupling via localized surface plasmon resonance is very challenging due to the lack of synthetic strategic principles with systematic structural control, all of which require a deep understanding of surface chemistry. Moreover, realizing those complex architectures with high homogeneity in size and shape via a bottom-up method where diverse particle interactions are involved is more challenging. Although there have been several reports on NFs used for catalysis, techniques for production of structurally complex NFs with high uniformity and an understanding of the correlation between such complexity in a single plasmonic entity and electromagnetic near-field focusing have remained highly elusive.In this Account, we will summarize and highlight the rational synthetic pathways for the design of complex two-dimensional (2D) and three-dimensional (3D) NFs with unique inner rim structures and characterize their optical properties. This systematic strategy is based on publications from our group during the last 10 years. First, we will introduce a chemical step of shape transformation of triangular Au nanoplates to circular and hexagonal plates, which are used as sacrificial layers for the formation of NFs. Then, we will describe the methods on how to synthesize monorim-based plasmonic NFs using Pt scaffolds with different shapes and correlate with their electromagnetic near-field. Then, we will describe a multiple stepwise synthetic method for the formation of 2D complex NFs wherein different starting Au nanocrystals evolved from systematic shape transformation are used to produce circular, triangular, hexagonal, crescent, and Y-shaped inner hot zones. Then, we will discuss how one can synthesize NFs with multiple rims wherein rims with different diameters are concentrically connected, by exploiting chemical toolkits such as eccentric and concentric growth of Au, borrowing the concept of total synthesis that is frequently adopted in organic chemistry. We then introduce dual-rim-faceted NFs and frame-in-frame 3D matryoshka NF geometries via well-faceted growth of Au with high control of intra-nanogaps. Finally, and importantly, we will provide examples of more advanced hierarchical NF architectures produced by controlling geometrical shapes of nanoparticles, number of rims, and different components, leading to the expansion of the NF library.

Accurate estimation of dynamical quantities for nonequilibrium nanoscale systems.

Fluctuations of dynamical quantities are fundamental and inevitable. For the booming research in nanotechnology, huge relative fluctuation comes with the reduction of system size, leading to large uncertainty for the estimates of dynamical quantities. Thus, increasing statistical efficiency, i.e., reducing the number of samples required to achieve a given accuracy, is of great significance for accurate estimation. Here we propose a theory as a fundamental solution for such problem by constructing auxiliary path for each real path. The states on auxiliary paths constitute canonical ensemble and share the same macroscopic properties (NVT) with the initial states of the real path. By implementing the theory in molecular dynamics simulations, we obtain a nanoscale Couette flow field with an accuracy of 0.2μm/s with relative standard error <0.1. The required number of samples is reduced by 12 orders compared to conventional method. The predicted thermolubric behavior of water sliding on a self-assembled surface is directly validated by experiment under the same velocity. This theory only assumes the system is initially in thermal equilibrium, then driven from that equilibrium by an external perturbation. It could serve as a general approach for extracting the accurate estimate of dynamical quantities from large fluctuations to provide insights on atomic level under experimental conditions, and benefit the studies on mass transport through (biological) nanochannels and fluid film lubrication of nanometer thickness.

Synthesis of Iron oxide Nanoparticle using Propolis from Northern Cyprus and Evaluation of its Antibacterial, Anticancer Potential on MDA-MB 231 cells

Research in nanotechnology has progressed in the last decades, and it is purposeful to explore the applications of biocompatible nanoparticles in general and their anticancer attribute specifically. This study is aimed at examining the cytotoxic effects of biocompatible Northern Cyprus propolis extract of iron oxide nanoparticles (PE-Fe2O3-NPs) on MDA-MB-231 epithelial human breast cancer cell line, in vitro. Propolis extract were used to obtain PE-Fe2O3-NPs and further characterized using several methods like ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, scanning electronic microscopy and X-ray diffraction analysis. The PE-Fe2O3-NPs has a distinctive Surface Plasmon Resonance band at 350 nm. The prepared PE-Fe2O3-NPs had a size of 108 nm by diameter with a zeta potential of +33.9 mV which indicates a good stability of the nanoparticles’ while the size of Fe2O3-NPs was 89.40 nm by diameter. Antibacterial result showed that Fe2O3-NPs has highest Minimum Inhibitory Concentration and Minimum Bactericidal Concentration as compared to PE-Fe2O3-NPs with different concentration of propolis extract as regards the tested microorganisms. This indicates that PE-Fe2O3-NPs possesses a more effective threat to eliminating pathogenic bacteria at lesser dosages, be it Gram-ve or Gram+ve. PE-Fe2O3-NPs effectively halted the spread of MDA-MB-231 cancer cell lines and thus, prove to be commendable for anticancer biomedical uses.

Antipyretic Medicinal Plants, Phytocompounds, and Green Nanoparticles: An Updated Review.

Pyrexia itself is not a terminal condition. Basically, it occurs with mild to serious diseases affecting alarge population of the world. Other than a high body temperature, pyrexia is accompanied by several sickness behaviors, changes in physiological and metabolic characteristics of the body system, and alterations in the immune responses. Various allopathic drugs are available to treat pyrexia by targeting the symptom or the pathogen itself. Drug-resistance has made control and treatment of vectors more difficult. However, many marginal people are obligated to utilize locally available medicinal plants for the treatment of various diseases due to limited access to synthetic drugs. Developments in the field of nanotechnology and phytochemical research towards the discovery of new antimicrobial agents have also drawn the interest of researchers towards the synthesis of green nanoparticles from plant extracts due to their several benefits over the other methods. Thus, the present report discusses the use of ethnomedicinal plants, phytocompounds, and the application of green nanoparticles synthesized from plant extracts to treat pyrexia.

Synthesis of Metallic Nanoparticles Based on Green Chemistry and Their Medical Biochemical Applications: Synthesis of Metallic Nanoparticles

Nanoparticles have distinct properties that make them potentially valuable in a variety of industries. As a result, emerging approaches for the manufacture of nanoparticles are gaining a lot of scientific interest. The biological pathway of nanoparticle synthesis has been suggested as an effective, affordable, and environmentally safe method. Synthesis of nanoparticles through physical and chemical processes uses unsafe materials, expensive equipment and adversely affects the environment. As a result, in order to support the increased utilization of nanoparticles across many sectors, nanotechnology research activities have shifted toward environmentally safe and cost-effective techniques that outperform chemical and/or biological procedures. The use of organisms to produce metal nanoparticles is among the most frequently discussed methods. Plants appear to be the best candidates among these organisms for large-scale nanoparticle biosynthesis. Medicinal plants have been employed as reducing agents and NP stabilizers to minimize the toxicity of NPs in both the environment and the human body. Furthermore, the presence of certain functional components in plant extracts may be extremely useful and effective for the human body. Polyphenol, for example, which may have antioxidant properties, might intercept free radicals before they interact with other biomolecules and cause considerable damage. The current article analyzes the most recent developments and improvements in the green synthesis of metal nanoparticles by different plants and the use of these nanoparticles for various biomedical applications and hopes to provide insights into this exciting research frontier.

The application of gold nanoparticles in biomedicine

In the past few years, nano particles are one of the most popular scientific research fields. It has been widely used in biomedical, optics, electronics and other areas. Gold nanoparticles are quite different from other nanoparticles. Their practical application has a very long history, which has been recorded in ancient Rome. By using their scattering property, gold nanoparticles are added to glass products to make them not only have various colors, but also have photochromic effect. With the development of related fields such as new organic metal chemistry, nanotechnology, and complex research, gold nanoparticles are listed as an important research object in biomedical applications. The shape and size of gold nanoparticles have a direct impact on their optical properties and applications. Therefore, exploring the preparation method to achieve controllable preparation is of great significance for the research of gold nanoparticles. Moreover, the application research of nano gold in biomedicine filed has developed rapidly, especially in recent years. Gold nanoparticles play an increasingly important role in disease detection, targeted therapy, drug detection, enhanced device performance, and imaging. This work mainly discusses the preparation method of gold nanoparticles and its applications in biomedicine field.

Synthesis of Nickel Oxide Nanoparticles and Copper-Doped Nickel Oxide Nanocomposites Using Phytolacca dodecandra L'Herit Leaf Extract and Evaluation of Its Antioxidant and Photocatalytic Activities.

Nanotechnology research is emerging as cutting-edge technology, and nanoparticles (NPs) and nanocomposites (NCs) have played a significant role in the bioremediation and treatment of polluted water by organic and nonorganic materials. Nanoparticles produced by plant extracts are more stable and biocompatible in comparison with those produced by physical and chemical methods. This research focuses on the synthesis of NiO NPs and Cu-NiO NCs using Phytolacca dodecandra L'Herit (P.d) leaf extract and evaluation of their antioxidant and photocatalytic activities. Cu-NiO NCs were synthesized using 50 mL of 0.1 M nickel(II) nitrate hexahydrate, 10 mL of 0.1 M copper(II) nitrate trihydrate, and 20 mL of leaf extract. The synthesized nanoparticles were characterized by UV-vis, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) analyses to study the energy band gap, average crystallite size, functional groups, and morphology of the samples, respectively. The UV-vis analysis showed a red shift after copper doping, indicating a decrease in the optical band gap values. FT-IR characterization confirms the presence of various functional groups in samples. Crystallite sizes of the formed particles were obtained to be 14.18 and 16.10 nm from the XRD data for NiO NPs and Cu-NiO NCs, respectively. SEM showed the crystallinity of particles with a cubic structure. The photocatalytic degradation of methylene blue (MB) was found to be 78.3 and 97.8% by NiO NPs and Cu-NiO NCs, respectively. In the antioxidant test, NiO NPs and Cu-NiO NCs prevented the oxidation of 50% of the H2O2 molecules at a concentration of 363.96 and 350.29 μg/mL, respectively. Finally, the synthesized samples showed good photocatalytic and antioxidant activities.

Current status and trends in the physicochemical properties of nanomaterials and nanotechnology researches

Current status and trends in the physicochemical properties of nanomaterials and nanotechnology researches

Recent advance in two-dimensional MXenes: New horizons in flexible batteries and supercapacitors technologies

MXenes (two dimensional (2D) transition metal (TM) carbides (TMCs), TM nitrides (TMNs), and TM carbonitrides (TMCNs) are emerged as future biggest 2D materials (2DMs) family with novel applications in different nanotechnological research in academic as well as industrial level. MXenes NMs have the potential to be classified as a “wonder material” in the category of 2D nanomaterials (NMs). MXenes were studied and synthesized for over a decade since their first discovery in 2011, and till now more than 50 members are experimentally studied and more than 100 are theoretically investigated. Synthesis techniques are not restricted to the first introduced top-down HF based etching method but new innovative synthesis methods, such as, water (H 2 O)-free etching, molten salts etching and bottom-up method, like Chemical vapor deposition (CVD) method etc were also studied, providing multifunctional surface chemistry based MXenes NMs with novel configuration, and desirable characteristics. MXenes are used as important components in a number of flexible energy storage devices (FESDs), for instance secondary batteries, supercapacitors (SCs), Micro-SCs (MSCs) and Micro-batteries (MBs), etc due to their distinctive layered structures, high electrochemical performance and fascinating functional capabilities. In this review, we first will discuss in detail the MXenes NMs synthesis methods, secondly selected properties, and third their applications in various FESDs. After that, we will summarize and discuss the most present problems associated with MXenes NMs synthesis and their applications in FESDs, and possible solutions to those problems. Finally we will discuss the presents interesting vision for the future progress of the MXenes-based NMs in wearable and FESDs, their limitations, and suggestions.

Analyzing research outcomes and spillovers at a US nanotechnology user facility

This paper maps research outcomes and identifies spillover effects at a US University Research Center (URC) that offers user facilities for nanotechnology research. We use scientometric and network science approaches to analyze measures of topical orientation, productivity, impact, and collaboration applied to URC-related Web of Science abstract publications records. A focus is on the analysis of spillover effects on external organizations (i.e., non-affiliated users). Our findings suggest the URC’s network relies on external organizations acting as brokers, to provide access to the facilities to other external organizations. Analysis of heterophily indicates that collaboration among internal and external organizations is enhanced by the facilities, while articles written by a mix of co-authors affiliated with internal and external organizations are likely to be more cited. These results provide insights on how URCs with user facilities can create conditions for diverse collaboration and greater research impact.

Manganese oxide nanoparticles synthesis route, characterization and optical properties

Synthesis of nanoparticles in the nanotechnology research field, which enhances the development of eco-friendly methods. Chemical co– precipitation method is used for the synthesis of MnO nanoparticles were annealed the precursor, by operating under Muffle Furnace, have been synthesized with the help of salt such as manganese acetate by using NaOH solution. The optical analysis measured by UV–VISIBLE spectroscopy, showed that the optical properties of the nanoparticles were analyzed, the absorption peak at 328 nm and UV–visible spectrum exhibited the prominent absorption. Particle size and morphology analysis carried by Scanning Electron Microscopy (SEM) showed that open and semi linear structures. Elemental composition measured by Energy Dispersive Analysis (EDX). Hexagonal structures were carried out by using High Resolution-Transmission Electron Microscopy (HR-TEM), exhibits pure single crystalline structures and SAED which confirms the purity of the synthesized sample. Manganese dioxide nanoparticles are one of the most attractive inorganic materials with high range of physical and chemical applications on it because of characteristic nature and its ease preparation, massive optical properties showed that it is eligible for application on photovoltaic cells.

Synthesis and characterization of cefixime loaded silver nanoparticles for antibacterial activity against staphylococcus aureus

In Recent year's medication obstruction is a quickly developing issue over the whole world in the treatment of infectious diseases. The widespread use of broad-spectrum antibiotics produced antibiotic resistance for many human bacterial pathogens. Anyways right now, nanotechnology research has been engaging more in restorative businesses with various advantages because of the way that surface area to volume proportion of Nanoparticles is quite large. In this exploration work, Silver Nanoparticles (AgNPs) are prepared by using a reducing agent like sodium borohydride and capping agent Polyvinylpyrrolidone. The prepared AgNPs and Cefixime-loaded AgNPs were subjected to characterization like particle size, FT-IR, X-ray diffraction. In addition, the AgNPs draw much interest in the account of their powerful antibacterial movement. The antibacterial activity of AgNPs and Cefixime-loaded AgNPs was checked against the bacterial culture of Staphylococcus Aureus. The zone of inhibition AgNPs was checked against microorganisms. The results of this study demonstrate the antibacterial activity of AgNPs and Cefixime-loaded Silver Nanoparticles against the bacterial culture of Staphylococcus Aureus with synergistic activity

Nanotechnology-Based Strategies for Treatment of Obesity, Cancer and Anti-microbial Resistance: Highlights of the Department of Science and Innovation/Mintek Nanotechnology Innovation Centre Biolabels Research Node at the University of the Western Cape

Nanotechnology has recently received much interest in various fields, including medicine. South Africa (SA) was the first country in Africa to adopt the technology with the aim of enhancing the national bio-economy and global competitiveness by using innovative nanotechnology-based solutions. Since its inception in 2005 in SA, researchers have seized opportunities to increase and develop niche areas for its application in the health, energy, food, agriculture, and water sectors. We ventured into this field and have performed pioneering work on nanotechnology-based treatment strategies over the years. This perspective highlights the journey, with associated successes over the years, in order to display the impact of our nanotechnology research in health. The focus is on the nanotechnology outputs that have emanated from the Department of Science and Innovation (DSI)/Mintek Nanotechnology Innovation Centre (NIC) Biolabels Research Node (BRN) at the University of the Western Cape (UWC). BRN’s research interests were on nano-enabled materials for developing therapeutic agents, photothermal sensitizers, and targeted drug-delivery systems for treatment of chronic diseases and antimicrobial resistance.

The emerging role of cancer nanotechnology in the panorama of sarcoma.

In the field of nanomedicine a multitude of nanovectors have been developed for cancer application. In this regard, a less exploited target is represented by connective tissue. Sarcoma lesions encompass a wide range of rare entities of mesenchymal origin affecting connective tissues. The extraordinary diversity and rarity of these mesenchymal tumors is reflected in their classification, grading and management which are still challenging. Although they include more than 70 histologic subtypes, the first line-treatment for advanced and metastatic sarcoma has remained unchanged in the last fifty years, excluding specific histotypes in which targeted therapy has emerged. The role of chemotherapy has not been completely elucidated and the outcomes are still very limited. At the beginning of the century, nano-sized particles clinically approved for other solid lesions were tested in these neoplasms but the results were anecdotal and the clinical benefit was not substantial. Recently, a new nanosystem formulation NBTXR3 for the treatment of sarcoma has landed in a phase 2-3 trial. The preliminary results are encouraging and could open new avenues for research in nanotechnology. This review provides an update on the recent advancements in the field of nanomedicine for sarcoma. In this regard, preclinical evidence especially focusing on the development of smart materials and drug delivery systems will be summarized. Moreover, the sarcoma patient management exploiting nanotechnology products will be summed up. Finally, an overlook on future perspectives will be provided.

(Invited) Synthesis, Functionalization, and Three-Dimensional Structuring of Carbon Nanomaterials By Gas-Liquid Interface Plasma

Carbon nanomaterials, such as fullerene, carbon nanotubes (CNT), graphene sheets, and so forth, play indispensable roles in nanotechnology research and applications. Due to their unique self-organized nanostructures and properties, various types of applications using them are expected and have been developed. One of recent hottest topics among them is graphene sheets and their electric device applications. High quality graphene sheets for such the device applications, epitaxial growth or chemical vapor deposition (CVD) methods at high temperature up to 1,000°C, are used as a synthesis method in general. On the other hand, some kinds of applications, such as sensors, batteries, additives to polymers, and so forth, need a large amount of nanographene power. For that purpose, a reduction of graphene oxide (GO) is well known, but the quality of the synthesized graphene is not high enough. Recently, we have established a high-speed synthesis method of nanographene materials with high crystallinity by a plasma discharge at gas-liquid interfaces with alcohol sources. By this method, a synthesis rate of nanographene over 1 mg/min and higher crystallinity of nanographene than the reduced GO have been realized. On the other hand, there is a trade-of relationship between the synthesis rate and crystallinity, when different types of alcohols were used as a feed stock gas. When ethanol,1-propanol, and 1-butanol were used, it was found that the higher synthesis rates were obtained by the higher-molecular weight alcohols, while its crystallinity was lower. In the comparison between hexane (C6H14) and hexanol (C6H13OH), in the case of hexane, the synthesis rate is about twice as high as that in the case of hexanol, but the crystallinity is lowered. These results indicate that this trade-of relationship is attributed to a ratio of carbon (C) and oxygen (O) atoms. O-related radicals (O, OH, etc.) in plasma could have etching effects of amorphous or low-crystallinity carbon components. Actually, according to the results of plasma diagnostic measurements and residual liquid analyses, it was found that crystallinity of nanographene materials degraded with decrease in OH intensity in plasma. Furthermore, small radicals such as C2 and CHx contribute to the synthesis of nanographene rather than by-products with a six-membered ring structure. Furthermore, we have also found functionalization and structural control of nanographene materials by additive agents to alcohol sources at in-liquid plasma processes. Using an iron phthalocyanine with ethanol, size of carbon nanosheets increased up to micrometer. And they showed excellent catalytic characteristics thorough 4-electron reduction pathway. According to the verification results of dependence on synthesis conditions such as the type of additive, such the catalytic activity is induced by pyridinic C-N bonds. In the case of this way, to increase pyridinic C-N bonds and improve catalytic performance, iron phthalocyanine is much better than Hemin, even which also included Fe and N. These knowledges obtained in this study will open the way to the next-generation green energy solutions, such as high-performance catalytic electrode for the fuel cell.