Download or read book Manganese Oxides as Electrocatalysts in Water Oxidation Synthesis Characterization and Their Activity in the Oxygen Evolution Reaction written by Justus Heese-Gärtlein and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Developing Enhanced Mixed Metal Oxide Catalysts for Electrocatalytic Water Oxidation Using Insights from X ray Absorption Spectroscopy written by Linsey C. Seitz and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Efficient and economic conversion of renewable energy sources is critical for development of technologies that can shift global energy dependence away from fossil fuels. Increased global energy consumption along with heightened awareness of environmental, health, and political issues with fossil fuels are driving the need for alternative technologies. Wind and sun provide more than enough energy to meet the growing energy demand, provided that challenges with intermittency, scale, and cost-effectiveness can be overcome. These obstacles can be mitigated through development of highly active catalysts using abundant and inexpensive materials to convert solar and wind energy into fuels and chemicals. One promising method of converting solar energy into fuel is by splitting water to produce hydrogen and oxygen. This can be achieved using a monolithic photoelectrochemical (PEC) water splitting device which combines photon-absorbing semiconductors with catalysts that drive the respective reactions or a photovoltaic/electrolyzer system which separates these two components. The first part of this thesis presents a model to quantify loss mechanisms in PEC water splitting based on the current state of materials research and calculate maximum solar-to-hydrogen (STH) conversion efficiencies. Results of this model indicate that a major limitation to the efficiency of solar-driven electrochemical water splitting is the oxygen evolution reaction (OER) which requires significant overpotential beyond the thermodynamic redox potential to proceed. The remainder of this dissertation focuses on understanding the interaction between metals in mixed metal oxide catalysts for the OER using electrochemical and advanced spectroscopic techniques towards the development of highly active and stable catalysts. Mixed metal oxide catalysts provide a robust platform for tuning binding energies of OER reaction intermediates to the catalyst surface, thereby affecting activity, through controlled material composition and geometry. We investigate two distinct mixed metal oxide catalyst systems using X-ray absorption spectroscopy (XAS) to probe local geometric and electronic structure and correlate the results with changes in activity. XAS is a synchrotron based technique which provides elemental-specific information by exciting electronic transitions from core to valence orbitals at various elemental edges. XAS studies at the Co K and L edges for a cobalt titanium oxide (CoTiOx) catalyst system identify stabilization effects on the Co oxidation state and overall structure from varying amounts of Ti precursor used during material synthesis. XAS before and after catalyst exposure to OER conditions indicate that catalysts with the least long range order become most oxidized and exhibit the highest activities. Similarly, in situ XAS at the Mn K and Au LIII edges reveal that there is a charge transfer at interfacial sites between manganese oxide (MnOx) and gold (Au) under OER conditions which coincides with significantly increased OER activity compared to MnOx without Au. Our results indicate that Au facilitates stabilization of more oxidized phases of Mn at lower overpotentials, thereby allowing for earlier onset of OER and higher activity. Lastly, we present an investigation of a novel mixed metal oxide catalyst, strontium iridium oxide (SrIrO3) which has the highest reported activity for any known OER catalyst. While it depends on use of Ir, a precious metal, its remarkably high activity compared to rutile IrO2 reduces the Ir loading necessary to achieve similar current densities. In summary, this dissertation explores a broad spectrum of catalysts for the oxygen evolution reaction and uses advanced material characterization methods to draw correlations between the structure, oxidation state, and catalytic activity for these materials. This work provides fundamental insight towards improving efficiency of electrochemical water oxidation processes for the conversion of renewable energy sources to fuels and chemicals.

Download or read book Metal Oxides and Related Solids for Electrocatalytic Water Splitting written by Junlei Qi and published by Elsevier. This book was released on 2022-05-16 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metal Oxides and Related Solids for Electrocatalytic Water Splitting reviews the fundamentals and strategies needed to design and fabricate metal oxide-based electrocatalysts. After an introduction to the key properties of transition metal oxides, materials engineering methods to optimize the performance of metal-oxide based electrocatalysts are discussed. Strategies reviewed include defect engineering, interface engineering and doping engineering. Other sections cover important categories of metal-oxide (and related solids) based catalysts, including layered hydroxides, metal chalcogenides, metal phosphides, metal nitrides, metal borides, and more. Each chapter introduces important properties and material design strategies, including composite and morphology design. There is also an emphasis on cost-effective materials design and fabrication for optimized performance for electrocatalytic water splitting applications. Lastly, the book touches on recently developed in-situ characterization methods applied to observe and control the material synthesis process. Introduces metal oxide-based materials for electrocatalytic water splitting applications, including their key properties, synthesis, design and fabrication strategies Reviews the most relevant materials design strategies, including defect engineering, interface engineering, and doping engineering Discusses the pros and cons of metal oxide-based materials for water splitting applications to aid in materials selection

Download or read book Metal Oxides Chalcogenides and Composites written by Aneeya Kumar Samantara and published by Springer. This book was released on 2019-08-09 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the recent development of metal oxides, hydroxides and their carbon composites for electrochemical oxidation of water in the production of hydrogen and oxygen as fuels. It includes a detailed discussion on synthesis methodologies for the metal oxides/hydroxides, structural/morphological characterizations, and the key parameters (Tafel plot, Turnover frequency, Faradic efficiency, overpotential, long cycle life etc.) needed to evaluate the electrocatalytic activity of the materials. Additionally, the mechanism behind the electro oxidation process is presented. Readers will find a comprehensive source on the close correlation between metal oxides, hydroxides, composites, and their properties and importance in the generation of hydrogen and oxygen from water. The depletion of fossil fuels from the earth’s crust, and related environmental issues such as climate change, demand that we search for alternative energy resources to achieve some form of sustainable future. In this regard, much scientific research has been devoted to technologies such as solar cells, wind turbines, fuel cells etc. Among them fuel cells attract much attention because of their versatility and efficiency. In fuel cells, different fuels such as hydrogen, CO2, alcohols, acids, methane, oxygen/air, etc. are used as the fuel, and catalysts are employed to produce a chemical reaction for generating electricity. Hence, it is very important to produce these fuels in an efficient, eco-friendly, and cost effective manner. The electrochemical splitting of water is an environmentally friendly process to produce hydrogen (the greener fuel used in fuel cells), but the efficiencies of these hydrogen evolution reactions (cathodic half reaction) are strongly dependent on the anodic half reaction (oxygen evolution reaction), i.e., the better the anodic half, the better will be the cathodic reaction. Further, this oxygen evolution reaction depends on the types of active electrocatalysts used. Though many more synthetic approaches have been explored and different electrocatalysts developed, oxide and hydroxide-based nanomaterials and composites (with graphene, carbon nanotubes etc.) show better performance. This may be due to the availability of more catalytic surface area and electro active centers to carry out the catalysis process.

Download or read book Photocatalysts written by Nasser S. Awwad and published by BoD – Books on Demand. This book was released on 2023-04-12 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes fourteen chapters on photocatalysis. It provides a thorough overview of the latest research on photocatalysts and examines recent trends in the field. Chapters address such topics as metal-organic frameworks, semiconductors, self–cleaning coatings and surfaces, the use of “green” agents to fabricate materials, fabrication of advanced nanocomposites for the production of hydrogen, bifunctional catalysts for metal-air batteries, and much more.

Download or read book Controlling the Oxygen Evolution Reaction Activity of Tunnel Manganese Oxide Via Post Synthesis Treatment written by Patrick Joseph West and published by . This book was released on 2018 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: To meet growing energy demands worldwide, both public and private entities have identified the production of hydrogen through environmentally conscious and economically viable means as a key bottleneck to the wide scale implementation of hydrogen fuel cells. One such promising route, electrolysis, requires the development of reliable catalysts to drive the sluggish and energy intensive oxygen evolution reaction (OER) and to improve the overall efficiency of the electrolysis process. Tunnel manganese oxides are attractive candidates for OER catalysis applications because of their high electrochemical activity and natural abundance, which make them fiscally appealing. Moreover, tunnel manganese oxide's open crystal structures allow for facile chemical manipulations of the cationic and anionic sublattices which in turn provides methods to control specific material attributes, such as oxidation state and vacancy concentration. In this work, acid leaching and transition metal doping approaches were investigated separately and sequentially to provide insights into how tunnel manganese oxides can be engineered on the atomic and micron scales to control OER activity.

Download or read book Metal Oxides as Electrocatalysts at Oxygen Electrodes in Electrochemical Systems written by Shuai Zhao and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells, one of the most widely studied electrochemical energy conversion devices, together with electrolyzers, a promising energy storage system for natural renewable energy and source of purified hydrogen, have attracted significant research attention in recent years as the demand for energy continues to increase with no end to this energy expansion in sight. However, electrochemical reactions occurring at oxygen electrodes such as the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) have very slow kinetics, which has limited the industrialization of both fuel cells and electrolyzers because slow kinetics leads directly high reaction overpotentials. Metal oxides have been widely adopted in terms of electrocatalysts for these oxygen reactions, either as as a support to enhance the stability or activity of platinum, or as the direct catalysts for ORR and OER in alkaline media. However, what is not known is how and why metal oxides as support materials can influence the performance of precious metals through their interactions, what the active sites are for different electrochemical reactions and how to control the desired phases by manipulating the synthesis conditions. This study will probe these very important questions. Chapter 1 of this work provides a background into the ORR/OER mechanism, active sites, and catalyst candidates in electrochemical devices. Chapter 2 presents experimental approaches including material synthesis, and both physical and electrochemical characterization. Chapters 3 and 4 of this study investigate doped metal carbides and metal oxides as support materials for platinum and iridium catalysts for the ORR and OER, respectively, in acidic electrolytes. The Chapter 3 is an investigation of tungsten carbide modified with titanium as a potential non-carbon support for platinum during the ORR in acid media. Chapter 4 discusses the relationship between the synthesis parameters of iridium/iridium oxide supported on titanium-doped tungsten oxide and its durability both ex-situ in a three-electrode cell on a rotating disk electrode (RDE) and in-situ in an operating electrolyzer. Chapter 5 discusses a new method to determine the electrochemically active area of iridium oxide, one of the most common anode catalysts in commercial PEM electrolyzers, in-situ through its electrochemical psuedocapacitance. Chapter 6 probes the performance and function of tin-doped indium oxides (ITO) as a support for platinum ORR catalyst in alkaline media. Metal-support interactions were studied mainly through X-ray photoelectron spectroscopy and electrochemical measurements. Chapter 7 focuses on the electrocatalysis of carbon nanotube (CNT)-supported cobalt oxide for both oxygen reduction and evolution reactions in alkaline media. An optimized procedure to produce a highly stable and active bifunctional ORR/OER hybrid catalyst was developed along with an understanding of the impact of metal oxide anchoring sites and synthesis parameters on catalyst durability. This part of the study provides novel perspectives for the design of carbon-based, hybrid materials and insight into the synthesis-property relationships for these and future electrocatalysts. In summary, this work has studied metal oxides as catalysts and support materials for precious metals during aqueous oxygen reactions. Wherever possible, the fundamental cause for their behavior, including enhanced electrocatalytic activity and durability, was probed thoroughly through physical and electrochemical characterization.

Download or read book Synthesis and Characterization of Mn Oxide Based Electrocatalysts for the Oxygen Reduction Reaction in the Zn Air Batteries written by 李柏潔 and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photo and Electro Catalytic Processes written by Jianmin Ma and published by John Wiley & Sons. This book was released on 2022-01-25 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore green catalytic reactions with this reference from a renowned leader in the field Green reactions—like photo-, photoelectro-, and electro-catalytic reactions—offer viable technologies to solve difficult problems without significant damage to the environment. In particular, some gas-involved reactions are especially useful in the creation of liquid fuels and cost-effective products. In Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction, award-winning researcher Jianmin Ma delivers a comprehensive overview of photo-, electro-, and photoelectron-catalysts in a variety of processes, including O2 reduction, CO2 reduction, N2 reduction, H2 production, water oxidation, oxygen evolution, and hydrogen evolution. The book offers detailed information on the underlying mechanisms, costs, and synthetic methods of catalysts. Filled with authoritative and critical information on green catalytic processes that promise to answer many of our most pressing energy and environmental questions, this book also includes: Thorough introductions to electrocatalytic oxygen reduction and evolution reactions, as well as electrocatalytic hydrogen evolution reactions Comprehensive explorations of electrocatalytic water splitting, CO2 reduction, and N2 reduction Practical discussions of photoelectrocatalytic H2 production, water splitting, and CO2 reduction In-depth examinations of photoelectrochemical oxygen evolution and nitrogen reduction Perfect for catalytic chemists and photochemists, Photo- and Electro-Catalytic Processes: Water Splitting, N2 Fixing, CO2 Reduction also belongs in the libraries of materials scientists and inorganic chemists seeking a one-stop resource on the novel aspects of photo-, electro-, and photoelectro-catalytic reactions.

Download or read book Nanomaterials for Electrochemical Energy Storage Devices written by Poulomi Roy and published by John Wiley & Sons. This book was released on 2019-10-14 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy storage devices are considered to be an important field of interest for researchers worldwide. Batteries and supercapacitors are therefore extensively studied and progressively evolving. The book not only emphasizes the fundamental theories, electrochemical mechanism and its computational view point, but also discusses recent developments in electrode designing based on nanomaterials, separators, fabrication of advanced devices and their performances.

Download or read book Electrochemical Oxygen Reduction written by Pei Kang Shen and published by Springer Nature. This book was released on 2021-01-16 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses systematically the theoretical research and the applications of electrochemical oxygen reduction. Oxygen reduction reaction is a common issue in electrochemistry, but is also an important process involved in the field of energy, cryogenic fuel cells, metal–air cells, oxygen sensors and hydrogen peroxide preparation. This book is divided into 6 chapters; it starts with a description of dynamic mechanisms, followed by a detailed introduction on the related experimental methods and related catalyst preparation technology. By providing the basic methods and testing techniques, and by demonstrating their applications, it helps readers gain a better understanding of oxygen reduction reactions, making it a valuable resource for the industrialization of scientific research achievements. Accordingly, the book appeals to a broad readership, particularly graduate students, those working at universities and research organizations, and industrial researchers.

Download or read book Single Atom Catalysts written by Prashanth W. Menezes and published by Elsevier. This book was released on 2024-01-22 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Single Atom Catalysts: Design, Synthesis, Characterization, and Applications in Energy focuses on the synthesis, design and advanced characterization techniques for single atom catalyst materials and their direct energy conversion and storage applications. This book reviews emerging applications of single atom catalysts in fuel cells, batteries, water splitting, carbon dioxide reduction, and nitrogen fixation. Both noble metal and non-noble metal single atom catalysts (SACs) are discussed as noble metal-based SACs are highly efficient and non-noble metal-based SACs might have lower associated costs. There is an emphasis on materials design focused on improving performance of catalysts based on overall catalytic activity, selectivity and stability. Specific parameters that impact this performance are emphasized throughout the book, including single metal atom stabilization, metal-support interactions and the coordination environment. Discusses the different intricate design and synthesis methods pertaining to various noble and non-noble metal-based SACs Provides in-depth understanding about the structural, morphological, and physicochemical characterization techniques of synthesized SACs with data analysis and interpretation Describes state-of-the-art applications of SACs in renewable energy generation and their conversion, storage, and associated challenges

Download or read book Mesoporous Manganese Oxide Materials for Aerobic Oxidation Reactions written by Sourav Biswas and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The thesis presented here is focused on fabricating thermally stable and tunable mesoporous manganese oxide materials for catalytic aerobic oxidation reactions. From the viewpoint of green chemistry, the design of novel methodologies for oxidation, preferably under aerobic atmospheric condition, without any additives is highly desirable. Being motivated by advances in catalytic materials as fundamental pillars of â€green chemistry’, my research is devoted to designing of useful materials in oxidative catalysis that may serve the purpose of sustainable energy sources in harmony with the environment and nature. The five chapters provided here will discuss the importance of catalytic oxidation reactions, synthesis, and characterization of the mesoporous manganese oxide materials and their applications in a series of simple to complex oxidation reactions. We demonstrate the activity enhancement of mesoporous manganese oxide materials by introducing alkali metal ions in a simple alcohol oxidation reaction. The major achievement of this work is inventing a cesium ion promoted mesoporous manganese oxide, which was found to be active in a multitude of aerobic oxidation reactions. In terms of catalytic oxidation reactions, oxidation of alcohol to aldehydes, amines to imines, a versatile one –pot tandem oxidation processes and oxidative coupling of alkynes have been discussed. Moreover, mechanistic aspects of catalytic oxidation are studied in details, especially the role of the surface oxygen species, oxygen vacancies and related oxygen transportation of the metal oxides. The catalytic oxidation protocols discussed here have several advantages over the existing systems in addressing the goals of green chemistry. First, the heterogeneous nature of the catalyst provides ease of separation of product. Next, excellent reusability of the catalyst (as high as 8 cycles) and formation of water as the only by-product (in most of the cases) reduces toxic waste production. Finally, absence of additives and use of air as the terminal oxidant exemplify the greener, more efficient and less expensive nature of these processes.

Download or read book Development of Manganese Oxide Based Catalysts for the Oxygen Reduction and Oxygen Evolution Reactions written by Yelena Gorlin and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of active catalytic materials for the oxygen reduction reaction (ORR, O2 + 4H+ + 4e- 2!2H2O) and the oxygen evolution reaction (OER, 2H2O 2!O2 + 4H+ + 4e- ) is one of the major challenges in energy conversion and storage technologies such as fuel cells, metal-air batteries, electrolysis cells, and solar fuel synthesis. The majority of industrially relevant active materials are precious metals and metal oxides, whose high cost and scarcity limits the widespread adoption of these important technologies. Manganese oxides (MnOx) catalysts are an interesting alternative to the precious metal based electrodes under alkaline conditions due to their abundance, low cost, and a demonstrated ability to catalyze both the ORR and the OER at high pH values. To accelerate the development of MnOx catalysts with improved activities for the ORR and the OER, it is important to increase understanding of the surface properties at the ORR and the OER relevant potentials. Spectroscopy techniques, including x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XAS), are among the possible methods to monitor surface chemistry of catalytic materials. Both XPS and XAS can offer information on the electronic structure of the surface, while XAS can also probe the short-range order of the catalysts. This dissertation focuses on development of MnOx catalysts for the ORR and the OER and uses ex-situ XPS, ex-situ Mn L-edge XAS, and in-situ Mn K-edge XAS to correlate measured catalytic activity to the surface oxidation state of Mn.

Download or read book Photochemical Water Oxidation by Zeolite supported Manganese Oxides written by Sweta Shrestha and published by . This book was released on 2014 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work zeolite supported manganese oxide (MnOx-Y(Cl)) clusters were studied for photochemical water oxidation. Zeolite-supported manganese oxides were synthesized by ion exchanging of cations (Mn2+ ions with or without alkaline earth metals cations) within zeolite channels and cavities followed by precipitation of manganese oxides on the surface of zeolite. Two types of catalysts were prepared: zeolite-supported manganese oxides (MnOx-Y(Cl)) and zeolite-supported alkaline earth metal cations (N) doped manganese oxides (NMnOx_Y(Cl)). Mn oxides without any support were also prepared. SEM micrographs confirmed the deposition of particles on the zeolite surface with sizes ranging from 50-80 nm. XRD diffraction patterns showed that both MnOx-Y(Cl) and NMnOx-Y(Cl) are hexagonal birnessite type (poorly ordered) layered structure MnO2. Raman scattering also showed that these manganese oxides on the zeolite surface are edge sharing MnO6 octahedra chains, as found in birnessite. XPS characterization showed that all samples had Mn valences as in birnessite. Sacrificial photochemical water oxidation using Ru(bpy)32+-persulfate system showed that zeolite supported catalysts have better catalytic performance compared to non-supported catalysts. It is proposed that the zeolite support provides better dispersion of manganese oxides on its surface, and it brings both photosensitizer and catalysts in close proximity for water oxidation. NMnOx-Y(Cl) were better catalysts than MnOx-Y(Cl) in water oxidation, and we propose that alkaline earth metals provide structural stability and integrity of the Mn oxide structure and enhances its catalytic activity. Among NMnOx-Y(Cl) catalysts, Ba2+ doped Mn oxides (BaMnOx-Y(Cl)) were the best catalysts, and is correlated with the observation that MnOx in BaMnOx-Y(Cl) possess increased surface area exposing more active sites for water oxidation. Overall, alkaline earth metals with the largest cation doped manganese oxides zeolite supported catalysts are found to be the most active water oxidizing catalyst.

Download or read book Electrochemical Water Splitting written by Inamuddin and published by Materials Research Forum LLC. This book was released on 2019-10-25 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aiming at the generation of hydrogen from water, electrochemical water splitting represents a promising clean technology for generating a renewable energy resource. The book reviews the fundamental aspects and describes recent research advances. Properties and characterization methods for various types of electrocatalysts are discussed, including noble metals, earth-abundant metals, metal-organic frameworks, carbon nanomaterials and polymers. Keywords: Electrochemical Water Splitting, Renewable Energy Resource, Electrocatalysts, Oxygen Evolution Reaction (OER), Noble Metal Catalysts, Earth-Abundant Metal Catalysts, MOF Catalysts, Carbon-based Nanocatalysts, Polymer Catalysts, Transition Metal-based Electrocatalysts, Fe-based Electrocatalysts, Co-based Electrocatalysts, Ni-based Electrocatalysts, Metal Free Catalysts, Transition-Metal Chalcogenides, Prussian Blue Analogues.

Download or read book Sustainable Materials and Green Processing for Energy Conversion written by Kuan Yew Cheong and published by Elsevier. This book was released on 2021-10-01 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sustainable Materials and Green Processing for Energy Conversion provides a concise reference on green processing and synthesis of materials required for the next generation of devices used in renewable energy conversion and storage. The book covers the processing of bio-organic materials, environmentally-friendly organic and inorganic sources of materials, synthetic green chemistry, bioresorbable and transient properties of functional materials, and the concept of sustainable material design. The book features chapters by worldwide experts and is an important reference for students, researchers, and engineers interested in gaining extensive knowledge concerning green processing of sustainable, green functional materials for next generation energy devices. Additionally, functional materials used in energy devices must also be able to degrade and decompose with minimum energy after being disposed of at their end-of-life. Environmental pollution is one of the global crises that endangers the life cycles of living things. There are multiple root causes of this pollution, including industrialization that demands a huge supply of raw materials for the production of products related to meeting the demands of the Internet-of-Things. As a result, improvement of material and product life cycles by incorporation of green, sustainable principles is essential to address this challenging issue. Offers a resourceful reference for readers interested in green processing of environmentally-friendly and sustainable materials for energy conversion and storage devices Focuses on designing of materials through green-processing concepts Highlights challenges and opportunities in green processing of renewable materials for energy devices