Synthesis And Characterization Of Novel Carbon Nanostructures Supported Catalysts And Their Effects On Methanol And Ethanol Electro Oxidation

Alternative energy conversion systems are receiving great attention due to the depletion of fossil fuels and increasing environmental pollution. Due to excellent features such as high energy density, low operating temperature, and high energy conversion efficiency, direct methanol (DMFC) and ethanol fuel cells (DEFC) are promising power sources to address future energy problems. However, their performance is limited by low electrocatalytic activity of anodes for methanol and ethanol oxidations, and the high cost of noble metal platinum (Pt) based catalysts. One approach to enhance catalytic activity and to reduce the cost is to explore novel carbon materials as catalyst supports. In this work, single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and graphene-supported Pt and Pt-Ru catalysts were synthesized by an ethylene glycol (EG) reduction method. Comparative electrochemical measurements of different carbon structure-supported catalysts were conducted using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry techniques. Experimental results show that SWCNT-supported Pt and Pt-Ru catalysts have a higher catalytic activity and lower charge transfer resistance towards methanol and ethanol oxidation in comparison to MWCNT-supported catalysts. The electrocatalytic activities of graphene-supported catalysts were compared with commercial Vulcan XC-72 carbon black-supported catalysts and graphite supported catalysts. Experimental results suggest that graphene-supported Pt and Pt-Ru nanoparticles possess superior electrocatalytic activity than carbon black and graphite supports.

Nanomaterials for Direct Alcohol Fuel Cells explains nanomaterials and nanocomposites as well as the characterization, manufacturing, and design of alcohol fuel cell applications. The advantages of direct alcohol fuel cells (DAFCs) are significant for reliable and long-lasting portable power sources used in devices such as mobile phones and computers. Even though substantial improvements have been made in DAFC systems over the last decade, more effort is needed to commercialize DAFCs by producing durable, low-cost, and smaller-sized devices. Nanomaterials have an important role to play in achieving this aim. The use of nanotechnology in DAFCs is vital due to their role in the synthesis of nanocatalysts within the manufacturing process. Lately, nanocatalysts containing carbon such as graphene, carbon nanotubes, and carbon nanocoils have also attracted much attention. When compared to traditional materials, carbon-based materials have unique advantages, such as high corrosion resistance, better electrical conductivity, and less catalyst poisoning. This book also covers different aspects of nanocomposites fabrication, including their preparation, design, and characterization techniques for their fuel cell applications. This book is an important reference source for materials scientists, engineers, energy scientists, and electrochemists who are seeking to improve their understanding of how nanomaterials are being used to enhance the efficiency and lower the cost of DAFCs. Shows how nanomaterials are being used for the design and manufacture of DAFCs Explores how nanotechnology is being used to enhance the synthesis and catalysis processes to create the next generation of fuel cells Assesses the major challenges of producing nanomaterial-based DAFCs on an industrial scale

Comprehensive Nanoscience and Technology, Second Edition, Five Volume Set allows researchers to navigate a very diverse, interdisciplinary and rapidly-changing field with up-to-date, comprehensive and authoritative coverage of every aspect of modern nanoscience and nanotechnology. Presents new chapters on the latest developments in the field Covers topics not discussed to this degree of detail in other works, such as biological devices and applications of nanotechnology Compiled and written by top international authorities in the field

This volume covers all aspects of carbon and oxide based nanostructured materials. The topics include synthesis, characterization and application of carbon-based namely carbon nanotubes, carbon nanofibres, fullerenes, carbon filled composites etc. In addition, metal oxides namely, ZnO, TiO2, Fe2O3, ferrites, garnets etc., for various applications like sensors, solar cells, transformers, antennas, catalysts, batteries, lubricants, are presented. The book also includes the modeling of oxide and carbon based nanomaterials. The book covers the topics: Synthesis, characterization and application of carbon nanotubes, carbon nanofibres, fullerenes Synthesis, characterization and application of oxide based nanomaterials. Nanostructured magnetic and electric materials and their applications. Nanostructured materials for petro-chemical industry. Oxide and carbon based thin films for electronics and sustainable energy. Theory, calculations and modeling of nanostructured materials.

Following in the lineage of Adsorption by Carbons (Bottani & Tascon, 2008), this work explores current research within contemporary novel carbon adsorbents. Both basic and applied aspects are discussed for this important class of materials. The first section of the book introduces physical adsorption and carbonaceous materials, and is followed by a section concerning the fundamentals of adsorption by carbons. This leads to development of a series of theoretical concepts that serve as an introduction to the following section in which adsorption is mainly envisaged as a tool to characterize the porous texture and surface chemistry of carbons. Particular attention is paid to novel nanocarbons, and the electrochemistry of adsorption by carbons is also addressed. Finally, several important technological applications of gas and liquid adsorption by carbons in areas such as environmental protection and energy storage constitute the last section of the book. Encompasses fundamental science of adsorption by carbons, in one location, supporting current R&D without extensive literature review Describes adsorption as it is currently applied to major novel types of carbon materials, including carbon gels, carbide-derived carbons, zeolite-templated carbvons, hydrothermal carbons, carbon nanohorns and graphene Specific discussion of fuel storage, environmental remediation and biomedical applications, of contemporary interest to many surface chemists and applications-focused researchers

In this work, we describe the synthesis, structure, physical properties and some applications in catalysis of previously known carbon allotropes, and recently discovered carbon nanostructure (Chapter I). First, FB-OM-CVD deposition was used for metal or metal oxide deposition on metal oxide supports like alumina or silica, leading to the production of supported catalysts. The resulting material was used as catalyst for catalytic chemical vapor deposition of carbonaceous nanostructures i.e single- and multi-walled carbon nanotubes (SWCNTs, MWCNTs), carbon nanofibers (CNFs), and nitrogen doped carbon nanotubes (N-MWCNTs) and nanofibers (N-CNFs) (Chapter II). After catalyst removal by a H2SO4 or NaOH treatments and carboxylic surface group generation by a HNO3 treatment in the case of MWCNTs and CNFs, the carbon nanostructures were used as supports for heterogeneous catalysis. The hydrogenation of cinnamaldehyde was used as a model reaction to compare the performance of different bimetallic Pt-Ru catalysts as a function of the nature of the support. Detailed parametric studies as well as the effect of a heat treatment on the performance improvement of the Pt-Ru/MWCNT catalyst are presented. An explanation for the increase of performances upon heat treatment will be proposed after HREM, EDX, EXAFS and WAXS characterization of the catalyst (Chapter III). The prepared carbon nanostructures were also tested as supports for Pd based electrocatalysts for direct alkaline fuel cells applications in both cathodes for the ORR reaction and anodes for alcohols oxidation.

This book presents a state-of-the-art review on recent advances in nanocatalysts and electrocatalysis in DOFCs.

Low dimensional systems have revolutionized the science and technology in several areas. However, their understanding is still a great challenge for the scientific community. Solar energy conversion devices based on nanostructured materials have shown exceptional gains in efficiency and stability. In this context, nanostructures allow an improvement of surface properties, transport and charge transfer, as well as direct application as sensors and storage devices and energy conversion. This book discuss the recent advances and future trends of the nanoscience in solar energy conversion and storage. It explores and discusses recent developments both in theory as well as in experimental studies and is of interest to materials scientists, chemists, physicists and engineers.

Direct alcohol fuel cells (DAFCs) have received much attention from research academia because of their importance as alternative sources of energy. In this study, PdSn8/C, PdSn10 /C PdSn10.3, PdSn10.7/C, PdSn11/C and PdSn14/C (23 wt%) electrocatalysts on Vulcan XC72 carbon powder were prepared by impregnation reduction method and studied for the reaction of methanol and ethanol electrooxidation in an alkaline medium. The samples were characterized by X-ray Diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical characterization was performed using cyclic voltammetry (CV) and chronoamperometry (CA). It is found that for methanol and ethanol electrooxidation, PdSn10.7/C exhibited higher electrochemical performance than the commercial Pd/C. This realized high performance could be attributed to the generation of OH- species by Sn at lower potential.

This book describes a science and technology of a new type of electrocatalysts consisting of a single atomic layer of platinum on suitable supports. This development helped overcome three major obstacles—catalysts‘ cost, activity, and stability—for a broad range of fuel cell applications. The volume begins with a short introduction to the science of electrocatalysis, covering four reactions important for energy conversion in fuel cells. A description follows of the properties of metal monolayers on electrode surfaces, and underpotential deposition of metals. The authors then describe the concept of Pt monolayer electrocatalysts and its implications and their synthesis by galvanic displacement of less-noble metal monolayers and other methods. The main part of the book presents a discussion of catalysts’ characterization and catalytic properties of Pt monolayers for the four main reactions of electrochemical energy conversion: oxygen reduction and oxidation of hydrogen, methanol and ethanol. The book concludes with a treatment of scale-up syntheses, fuel cell tests, catalysts’ stability and application prospects.