Metal Oxide Carbon Research Articles

Enhancing energy and environmental metrics of aqueous ammonia emulsified diesel fuel using carbon-metal oxide nanocomposites: An experimental study

The study explores the impact of a zinc oxide (ZnO) induced carbon nanotube (CNT) nanocomposite on ammonia decomposition in aqueous ammonia (AA) emulsified diesel fuel, while evaluating performance and emissions. Functionalized CNTs induced with ZnO underwent structural and surface morphology analysis. Different concentrations of ammonium hydroxide (5 % and 10 %) were mixed with plain diesel fuel (PDF), and 100 ppm of ZnO/CNT was blended with 10 % AA emulsified fuel. Fuel performance was assessed under various brake power conditions compared to PDF. The results demonstrate that the absorption of latent heat by ammonia and its higher decomposition energy result in a longer ignition delay, thereby increasing peak in-cylinder pressure and net heat release rate. The post-combustion reaction of AA emulsified fuels contributes to increased brake specific fuel consumption (BSFC), brake specific energy consumption (BSEC), hydrocarbon (HC), carbon monoxide (CO), and smoke opacity. However, the dispersion of nanocomposite in AA emulsion enhances the catalytic effect and promotes ammonia decomposition, resulting in combustion characteristics similar to PDF. Notably, there is an observed improvement in BSFC by 8.1 % and BSEC by 10.9 %, respectively. Furthermore, emission metrics such as oxides of nitrogen, HC, CO, and smoke opacity decrease by 4.5 %, 18.8 %, 11.4 %, and 5 %, respectively.

Unveiling the Influential Factors and Heavy Industrial Applications of Graphene Hybrid Polymer Composites

Graphene hybrid-filler polymer composites have emerged as prominent materials that revolutionize heavy industries. This review paper encapsulates an in-depth analysis of different influential factors, such as filler/graphene type, aspect ratios, dispersion methods, filler-matrix compatibility, fiber orientation, synergistic effects, different processing techniques, and post-curing conditions, which affect the processing and properties of graphene hybrid polymer composites, as well as their resultant applications. Additionally, it discusses the substantial role of graphene reinforcement with other fillers, such as carbon nanotubes, silica, nano-clays, and metal oxides, to produce functionalized hybrid polymer composites with synergistically enhanced tailored properties, offering solutions for heavy industries, including aerospace, automotive, electronics, and energy harvesting. This review concludes with some suggestions and an outlook on the future of these composite materials by emphasizing the need for continued research to fully optimize their potential.

How Components of Dye-sensitized Solar Cells Contribute to Efficient Solar Energy Capture

Herein, we reviewed the main components of dye-sensitized solar cells (DSSCs) which are an emerging cheap and environmentally benign alternative for solar energy capture and conversion to electricity. The role of individual parts such as the semiconductor electrode, counter electrode, photosensitizer, electrolyte, and substrate and their contribution to the overall efficiency (η) of DSSCs are discussed. In addition, parameters such as short circuit current, open circuit voltage, and fill factor used to quantify the efficiency of DSSCs are addressed. The highest solar-to-electric energy conversion efficiency of 13 % has been achieved using titanium dioxide as a semiconductor electrode, a triiodide system as a redox couple, and platinum counter electrodes. Semiconductors are made up of materials such as glass, carbon, conductive polymers and other metal oxides have lower efficiencies (< 8 %). In addition, synthetic photosensitizers especially ruthenium complexes have higher efficiencies (10-11 %) compared to natural dyes among which the highest efficiency (4.6 %) was achieved using chlorophyll. The performance of natural dyes based on efficiency of the DSSC is generally in the order: chlorophyll > anthocyanins > carotenoids that is highly attributed to their structure which not only dictates electron release and recombination but also attachment to other components. The DSSC performance is not fixed but rather tunable by variations in the components to achieve desired structural and electronic properties such as firm anchorage between the photosensitizer and the semiconductors, the reduction of the energy band gap by incorporation of other metal salts to extend the absorption range and use of additives that prevent electron recombination with the photosensitizer or any hindrances in the electrolyte redox reactions.

Insights on the activity-selectivity trade-off in iron-containing nitrogen-doped carbon catalyst via cobalt addition for oxygen reduction reaction in alkaline medium

Iron-based noble-metal-free electrocatalysts exhibit impressive performance and stability for the Oxygen reduction reaction (ORR) in alkaline media, but face challenges. This study investigates the impact of Co addition to Fe in nitrogen(N)-doped carbon (Fe/NC) catalysts prepared via one-pot synthesis involving direct pyrolysis of the metal (M) and 2,4,6-tris(2-pyridyl)-s-triazine complexes (M-TPTZ) on carbon. Comprehensive characterization reveals N-doped carbon structures with single-atom sites and metal oxides, with M-Nx centers mainly in carbon pores and metal oxides on the carbon surface. N2 adsorption/desorption experiments and electrochemical surface area (ECSA) reveals that Co introduction enhances the catalyst surface area. Moreover, Co addition alters nitrogenated species distribution, affecting catalytic activity. Electrochemical studies rank catalytic activity as Fe/NC < Co/NC < CoFe/NC, while rotating ring-disk electrode (RRDE) investigations show mixed 2 and 4 electrons pathways. Fe/NC follows a 4e- pathway with minimal HO2− production, while Co-containing catalysts suggest a mixed (2e- + 2e-) pathway with an average of 3.75 electrons involved. This divergence highlights nuanced electrochemical characteristics of Fe- and Co-based materials, emphasizing the need for in-depth characterization.

Pt Catalysts Prepared via Top-down Electrochemical Approach: Synthesis Methodology and Support Effects

The synthesis of Pt nanoparticles and catalytically active materials using the electrochemical top-down approach involves dispersing Pt electrodes in an electrolyte solution containing alkali metal cations and support material powder using an alternating pulsed current. Platinum is dispersed to form particles with a predominant crystallographic orientation of Pt(100) and a particle size of approximately 7.6±1.0 nm. The dispersed platinum particles have an insignificant content of PtOx phase (0.25±0.03 wt.%). The average formation rate was 9.7±0.5 mg cm−2 h−1. The nature of the support (carbon material, metal oxide, carbon-metal oxide hybrid) had almost no effect on the formation rate of the Pt nanoparticles as well as their crystallographic properties. Depending on the nature of the support material, Pt-containing catalytic materials obtained by the electrochemical top-down approach showed good functional performance in fuel cell technologies (Pt/C), catalytic oxidation of CO (Pt/Al2O3) and electrochemical oxidation of methanol (Pt/TiO2-C) and ethanol (Pt/SnO2-C).

In-situ synthesis of encapsulated N-doped carbon metal oxide nanostructures for Zn-air battery applications

La, Mn and Co-based materials with diverse compositions encapsulated in N-doped carbon materials were synthesized by an in-situ sol-gel method. The as-prepared materials were physically activated with CO2 giving as a result composites with excellent performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The composites were characterized by different physicochemical techniques revealing the importance of porosity created by CO2 activation. This crucial step increases the number of accessible active sites such as Co-Nx-C sites, Co/MnO heterointerfaces and graphitic N groups. Moreover, the formation of La2O2CO3 was detected to enhance electrical conductivity and electrochemical performance and it is active for ORR. Although the composite containing La, Mn and Co has less concentration of the highly active sites, its small particle size favour a better distribution of these sites. The Co-containing composites were tested as air-electrodes in a Zn-air battery and compared to commercial electrocatalysts. All composites showed a better operation in terms of higher cyclability and higher energy density which is a consequence of metal nanostructures encapsulation in N-doped porous carbon shells. Interestingly, the pure Co-based composite showed an outstanding performance related to the high concentration of the Co-Nx-C active sites that provide high activity and stability.

Large-Scale Synthesis of Highly Porous CuO/Cu2O/Cu/Carbon Derived from Aerogels for Lithium-Ion Battery Anodes.

In this work, an effective strategy for the large-scale fabrication of highly porous CuO/Cu2O/Cu/carbon (P-Cu-C) has been established. Cu-cross-linked aerogels were first continuously prepared using a continuous flow mode to form uniform beads, which were transformed into P-Cu-C with a subsequent pyrolysis process. Various pyrolysis temperatures were used to form a series of P-Cu-C including P-Cu-C-250, P-Cu-C-200, P-Cu-C-350, and P-Cu-C-450 to investigate suitable pyrolysis conversion processes. The obtained P-Cu-C series were utilized as anodes of lithium-ion batteries, in which P-Cu-C-250 exhibited a higher reversible gravimetric capacity, excellent rate capability, and superior cycle stability. The enhanced behavior of P-Cu-C-250 was benefitted from the synergistic interaction between uniformly dispersed CuO, Cu2O, Cu nanoparticles, and highly graphitized carbon with a large surface area and highly porous structure. More importantly, the preparation of P-Cu-C-250 could be scaled up by taking advantage of the continuous flow synthesis mode, which may provide pilot- or industrial-scale applications. The large-scale fabrication proposed here may give a universal method to fabricate highly porous metal oxide-carbon anode materials for electrochemical energy conversion and storage applications. Porous CuO/Cu2O/Cu/carbon derived from Cu-crosslinked aerogels was used as Li-ion battery anode materials, exhibiting a high reversible areal capacity, large gravimetric capacity, superior cycling performance, and excellent rate capacity. A continuous preparation method is established to ensure the product scaled up.

Phthalocyanine and Porphyrin Derivatives and Their Hybrid Materials in Optical Sensors Based on the Phenomenon of Surface Plasmon Resonance

In this review, the state of research over the past fifteen years in the field of the applications of metal phthalocyanines and porphyrin derivatives as well as their hybrid materials with carbon nanotubes, metal oxides, and polymers in optical sensors based on the phenomenon of surface plasmon resonance (SPR) is analyzed. The first chapter of the review presents an analysis of works on the use of porphyrins and phthalocyanines in classical SPR sensors for the detection of gases and volatile organic vapors, as well as their improved modifications, such as total internal reflection ellipsometry (TIRE) and magneto-optical SPR (MOSPR) methods, while the second chapter is devoted to their application for the detection of various analytes in solutions. The third chapter of the review summarizes publications describing recent advances in the use of porous materials based on hybrids of carbon nanotubes and oxides with metal phthalocyanines. The fourth chapter describes two-dimensional metal-organic frameworks (MOFs) based on metal porphyrin derivatives as SPR sensitizers.

Preface

Preface Third International Conference on Physics of Materials & Nanotechnology (ICPN-2023) On behalf of Organizing committee, it’s my great pleasure to bring this beautiful collection of research articles which were presented in the Third International Conference on Physics of Materials and Nanotechnology (ICPN-2023) which was organized by Department of Physics, Mangalore University, Mangalagangothri, Mangalore (Karnataka), India during September 21st to 23rd, 2023. This conference will serve as an ideal platform for young researchers, academician and students from all over the country as well as from the globe to share their ideas and experiences in Physics, Nanotechnology and Nano science research. This conference provided meaningful platform for young researchers to update and upgrade themselves. The main themes of the conferences Advanced Energy and Solar Materials, 1-D, 2-D and Quantum dot Materials, Advanced Electronic Materials, Polymers, Conducting Polymer and Thin films, Solid State Materials and their properties, Sensors and actuators, Carbon related materials, Metal Oxide & Sulphide Materials, Ferroelectrics and dielectric materials, Soft, Magnetic and smart materials, Nano Material, Nanotechnology, Chemistry of Materials, Alloys, Semiconductor and optical Materials and Crystal growth & applications etc. I am glad that experts in the various field of Nanotechnology are here to present and discussed their ideas and latest development in the field. ICPN 2023 has received a great response throughout the country and globe. It includes 14 invited talks, 11 oral presentations and more than 120 poster presentations. We have received more than 130 papers for the publications in this issue, after reviewing and editing processes, 47 papers were accepted for the publication out of 74 submitted papers. We thank the authors for their contribution and the reviewers for their comments to improve the quality of article. I would like to express my gratitude to all members of organizing committee, staff, research scholars and postgraduate students of the institute for their willingness, commitment, dedication and relentless efforts in ensuring that conference was successful.List of Editorial Board is available in this pdf.

A new frontier of flexible energy devices: Aqueous proton supercapacitors

Aqueous proton supercapacitors are considered as promising energy storage devices for next-generation wearable electronics due to their high energy density, rapid kinetics, long cycles, and reliable safety. As of now, the research for electrochemical proton energy storage entails more holistic considerations. In this review, we provide a timely and comprehensive review of recent advances in electrochemical proton storage. First, we discuss the main explored proton storage electrode materials, including carbon materials, metal oxides, Prussian blue, COFs, and MXenes, from the aspects of structure, preparation strategy, and proton storage mechanism. Furthermore, we systematically focus on their multifunctional applications of proton supercapacitors including flexible and wearable electronics, anti-freezing energy storage system, etc. Finally, the challenges and prospects of flexible proton supercapacitors are outlined. We believe that this review will greatly improve the knowledge of proton energy storage and facilitate the development of advanced electrochemical energy systems.

Progress in Promising Semiconductor Materials for Efficient Photoelectrocatalytic Hydrogen Production.

Photoelectrocatalytic (PEC) water decomposition provides a promising method for converting solar energy into green hydrogen energy. Indeed, significant advances and improvements have been made in various fundamental aspects for cutting-edge applications, such as water splitting and hydrogen production. However, the fairly low PEC efficiency of water decomposition by a semiconductor photoelectrode and photocorrosion seriously restrict the practical application of photoelectrochemistry. In this review, the mechanisms of PEC water decomposition are first introduced to provide a solid understanding of the PEC process and ensure that this review is accessible to a wide range of readers. Afterwards, notable achievements to date are outlined, and unique approaches involving promising semiconductor materials for efficient PEC hydrogen production, including metal oxide, sulfide, and graphite-phase carbon nitride, are described. Finally, four strategies which can effectively improve the hydrogen production rate-morphological control, doping, heterojunction, and surface modification-are discussed.

Active-Matrix Array Based on Thin-Film Transistors Using Emerging Materials for Application: From Lab to Industry

The active-matrix technology incorporates a transistor to exert precise control over each pixel within a pixel array, eliminating the issue of crosstalk between neighboring pixels that is prevalent in the passive-matrix approach. Consequently, the active-matrix method facilitates the realization of high-resolution arrays, and this inherent advantage has propelled its widespread adoption, not only in display applications but also in diverse sensor arrays from lab to industry. In this comprehensive review, we delve into instances of active-matrix arrays utilizing thin-film transistors (TFTs) that leverage emerging materials such as organic semiconductors, metal oxide semiconductors, two-dimensional materials, and carbon nanotubes (CNTs). Our examination encompasses a broad classification of active-matrix research into two main categories: (i) displays and (ii) sensors. We not only assess the performance of TFTs based on emerging materials within the active-matrix framework, but also explore the evolving trends and directions in active-matrix-based displays and sensors.

Recent progress in the synthesis and applications of covalent organic framework-based composites.

Covalent organic frameworks (COFs) have historically been of interest to researchers in different areas due to their distinctive characteristics, including well-ordered pores, large specific surface area, and structural tunability. In the past few years, as COF synthesis techniques developed, COF-based composites fabricated by integrating COFs and other functional materials including various kinds of metal or metal oxide nanoparticles, ionic liquids, metal-organic frameworks, silica, polymers, enzymes and carbon nanomaterials have emerged as a novel kind of porous hybrid material. Herein, we first provide a thorough summary of advanced strategies for preparing COF-based composites; then, the emerging applications of COF-based composites in diverse fields due to their synergistic effects are systematically highlighted, including analytical chemistry (sensing, extraction, membrane separation, and chromatographic separation) and catalysis. Finally, the current challenges associated with future perspectives of COF-based composites are also briefly discussed to inspire the advancement of more COF-based composites with excellent properties.

Application of sulfur-based composite materials in the positive electrode of lithium-sulfur batteries

Traditional lithium-ion batteries are no longer able to keep up with the growing need for energy storage efficiency in areas like electric cars and renewable energy storage. Because of their great energy density, affordability, and environmental friendliness, lithium-sulfur batteries are regarded as a very promising solution for secondary battery systems. Sulfur-based compounds are an essential part of lithium-sulfur batteries and have a direct impact on the battery’s energy density and performance. However, sulfur-based compounds are easily soluble in electrolytes and have low conductivity, which shortens battery cycle life and energy efficiency. Sulfur dissolution can be successfully inhibited and capacitance may be enhanced by optimizing the structure and characteristics of sulfur-based materials, which will improve the overall performance of lithium-sulfur batteries. To enhance the performance of lithium-sulfur batteries, this article suggests three modification techniques for sulfur-based materials. These techniques mostly include compounding sulfur with carbon compounds, metal oxides, and polymers. This article also outlines the shortcomings of the present lithium-sulfur battery research and looks forward to the future development direction.

The application of plasma technology for the preparation of supercapacitor electrode materials.

With the rapidly growing demand for clean energy and energy interconnection, there is an urgent need for rapid and high-capacity energy storage technologies to realize large-scale energy storage, transfer energy, and establish the energy internet. Supercapacitors, which have advantages such as high specific capacitance, fast charging and discharging rates, and long cycle lifetimes, are being widely used in electric vehicles, information technology, aerospace, and other fields. The performance of supercapacitors is crucially dependent on electrode materials. These can be categorized into electric double-layer capacitors and pseudocapacitors, primarily made from carbon and transition metal oxides, respectively. However, effectively monitoring the physicochemical properties of electrode materials during preparation and processing is challenging, which limits the improvement of supercapacitors' performance. Plasma materials preparation technology can effectively affect the materials preparation processing by energetic electrons, ions, free radicals, and multiple effects in plasma, which are easily manipulated by operation parameters. Therefore, plasma material preparation technology is considered a promising method to precisely monitor the physicochemical and electrochemical properties of energy storage materials and has been widely studied. This paper provides an overview of plasma materials preparation mechanisms, and details of the plasma technology application in the preparation of transition metal hybrids, carbon, and composite electrode materials, as well as a comparison with traditional methods. In conclusion, the advantages, challenges, and research directions of plasma materials preparation technology in the field of electrode materials preparation are summarized.

Zinc Oxide-Loaded Cellulose-Based Carbon Gas Sensor for Selective Detection of Ammonia.

Cellulose-based carbon (CBC) is widely known for its porous structure and high specific surface area and is liable to adsorb gas molecules and macromolecular pollutants. However, the application of CBC in gas sensing has been little studied. In this paper, a ZnO/CBC heterojunction was formed by means of simple co-precipitation and high-temperature carbonization. As a new ammonia sensor, the prepared ZnO/CBC sensor can detect ammonia that the previous pure ZnO ammonia sensor cannot at room temperature. It has a great gas sensing response, stability, and selectivity to an ammonia concentration of 200 ppm. This study provides a new idea for the design and synthesis of biomass carbon-metal oxide composites.

Graphene‐Based Enzymatic and Non‐Enzymatic Electrochemical Glucose Sensors: Review of Current Research and Advances in Nanotechnology

AbstractThe determination of the body's glucose level is a difficult job that has served as the foundation for substantial research efforts in biosensing applications. Recent advances in material engineering and synthesis methodologies have had a significant influence on the development of enzymatic and non‐enzymatic sensors for glucose detection that may be used in managing diabetes, food technology, and clinical, and bio‐processing applications. The intricate fabrication, detecting principles and phenomena involved, material alterations, and design to improve sensor performance. There is a great need for high‐efficiency, low‐cost blood glucose sensors that may be used on industrial and domestic scales. This review is primarily intended to shed light on the current state of knowledge about the use of graphene. The performance of non‐enzymatic glucose sensors is comprehensively compared with that of enzymatic electrochemical sensors based on graphene. This study will go over the research efforts that have been conducted to build biosensors employing nanostructures such as carbon nanotubes, graphene, metal nanoparticles, metal oxides, and metal sulfides. The manufacturing of the very sensitive enzyme‐free glucose biosensor will be thoroughly discussed. A thorough examination of the use of graphene as a co‐catalyst to improve the sensitivity of electrochemical sensors for glucose detection is also provided.

Achieving enhanced tensile properties of polyurethane-multiwall carbon nanotubes nanocomposites

Polymeric nanocomposites have emerged as a promising class of materials with improved strength, stiffness, and toughness compared to pure polymers. The incorporation of nanoparticles into polymer matrices, such as carbon nanotubes, graphene, clay nanoparticles, and metal oxides, has shown considerable potential for enhancing the properties of the produced nanocomposites. Herein, the influence of filtered multiwalled carbon nanotubes (MWCNTs) on solution-cast polyurethane (PU) nanocomposite is explored. Scanning electron microscopy (SEM), x-ray diffraction (XRD), Raman spectroscopy, thermogravimetric analysis (TGA), and x-rays photoelectron spectroscopy (XPS), respectively, were employed to characterize the morphology, crystal structure, phase, thermal stability, and oxidation states of the samples. MWCNTs with a higher weight% of MWCNTs showcased superior mechanical properties compared to base polymer (PU). The nanocomposite with 1 wt% of MWCNTs and 99 wt% of PU exhibited the highest stress (19.25 N mm−2) and strain (700.22%) among all fabricated samples. Also, Modulus of elasticity (∼25%), Ultimate tensile strength (∼21%), and elongation at break (∼11%) are increased by incorporating 0.5 wt% MWCNTs into PU matrix. The attainment of these remarkable mechanical properties could be attributed to excellent dispersion, interfacial bonding and structural stability of filtered MWCNTs in the nanocomposites.

Diffusion controlled electrochemical analysis of MoS2 and MOF derived metal oxide–carbon hybrids for high performance supercapacitors

In the context of emerging electric devices, the demand for advanced energy storage materials has intensified. These materials must encompass both surface and diffusion-driven charge storage mechanisms. While diffusion-driven reactions offer high capacitance by utilizing the bulk of the material, their effectiveness diminishes at higher discharge rates. Conversely, surface-controlled reactions provide rapid charge/discharge rates and high power density. To strike a balance between these attributes, we devised a tri-composite material, TiO2/Carbon/MoS2 (T10/MoS2). This innovative design features a highly porous carbon core for efficient diffusion and redox-active MoS2 nanosheets on the surface. Leveraging these characteristics, the T10/MoS2 composite exhibited impressive specific capacitance (436 F/g at 5 mV/s), with a significant contribution from the diffusion-controlled process (82%). Furthermore, our symmetrical device achieved a notable energy density of ~ 50 Wh/kg at a power density of 1.3 kW/kg. This concept holds promise for extending the approach to other Metal–Organic Framework (MOF) structures, enabling enhanced diffusion-controlled processes in energy storage applications.

Metal-organic framework-derived LaFeO3@C: An adsorbent for removing organic dyes from water

Metal-Organic Frameworks (MOFs) and MOF-derived materials are emerging as a potential candidate in the field of adsorption owing to their vital properties of high surface area, tunable porosity and diverse functionalities. However, the instability of MOFs in harsh environmental conditions prompted to produce more stable forms of MOF-derived materials for adsorption applications. Carbonization of MOFs is becoming an efficient method to prepare stable metal oxide-carbon hybrids as adsorbents for pollutant removal. This study presents the first-time report on utilizing MIL-100(Fe)-derived mesoporous LaFeO3@C nanocomposites for the effective adsorption removal of methyl orange (MO) and sulforhodamine B (SRB). The nanocomposites having different surface chemistry and textural properties are formed from MOF-gel precursor by varying the calcination temperature in the argon atmosphere. The LaFeO3 nanoparticles in the nanocomposites crystallized into the orthorhombic structure, which is confirmed from the XRD, Micro-Raman and FTIR analysis. The material obtained at 700 °C (LFO@C-700) exhibited higher removal efficiency of 99% and 97.1% towards SRB and MO, respectively. The chemisorption is identified as the main rate-limiting step in adsorption and the isotherm follows the Langmuir model suggesting the monolayer coverage of the adsorbates. The successful elimination of dye contaminants from real water samples and industrial effluents by LFO@C-700 indicates the practical utility of this adsorbent material. Several key chemical interactions, including H-bonding, electrostatic interactions, π-π and cation-π interactions promote the adsorption process. Moreover, the LFO@C-700 nanocomposite shows reusability with sustainable adsorption for repeated experiment cycles, suggesting this adsorbent's cost-effective use in practical applications.