In this thesis, I will focus on the synthesis of transition metal oxide/sulfide-based composite materials for different types of environmental and sustainable energy applications under ambient conditions. Controlled synthesis of these catalysts with unique crystalline structures, physical, and chemical properties will be carried out to achieve an improved catalytic activity. The correlations between the material structure and catalytic activity will be investigated by various characterization techniques. Finally, the catalytic activities for the resulting materials will be evaluated for environmental friendly photocatalytic dye degradation and electrochemical water splitting reaction, respectively.
Nowadays, environmental concerns and the global energy crisis have become two of our greatest challenges. The main purpose of this dissertation research is to design highly active mesoporous materials that can efficiently catalyze environmental and energy related reactions. Surface properties can be easily tuned by thermal treatment and cation doping, resulting in improved catalytic activities. Synthesis and characterization of the materials, catalytic activities for carbon monoxide oxidation, oxygen reduction and oxygen evolution reactions, and mechanistic studies are covered in this thesis. The first part describes the synthesis of mesoporous cobalt oxides through an inverse micelle route for low temperature carbon monoxide oxidation applications. The prepared material showed much better activity and stability compared with commercial cobalt oxide due to its nanoparticle nature and porous structure. The catalytic performance under both dry and moisture rich conditions were tested. Detailed characterization of the materials suggested that high surface areas and the presence of surface oxygen vacancies were critical for enhanced activities. In real systems, structured catalysts such as monolithic substrates coated with a layer of active material are used instead of powder form catalysts. To evaluate the potential of our catalysts to be used in practical catalytic devices, mesoporous metal oxides (MnOx, Co3O4, CeO2) were coated on cordierite substrate by dip coating and in-situ growth and were used as low temperature diesel oxidation catalysts. The resulting materials showed promising catalytic performance. The effect of particle size, loading amount and Cu doping on the catalytic performance are discussed in detail. In the last part, mesoporous cobalt oxides were used as bifunctional catalysts for oxygen reduction and oxygen evolution reactions. If a catalyst can catalyze both reactions, it will have great potential in the application of rechargeable metal air batteries. Ni and Mn doping were introduced into the cobalt oxide material to increase the conductivity and active site population. The Ni incorporated cobalt oxide exhibited the best activity, which can be considered as a potential substituent for precious metal catalysts (Pt, Ir, Ru). Furthermore, the intrinsic structure-property relationships of the materials were established.
Metal Oxides in Heterogeneous Catalysis is an overview of the past, present and future of heterogeneous catalysis using metal oxides catalysts. The book presents the historical, theoretical, and practical aspects of metal oxide-based heterogeneous catalysis. Metal Oxides in Heterogeneous Catalysis deals with fundamental information on heterogeneous catalysis, including reaction mechanisms and kinetics approaches.There is also a focus on the classification of metal oxides used as catalysts, preparation methods and touches on zeolites, mesoporous materials and Metal-organic frameworks (MOFs) in catalysis. It will touch on acid or base-type reactions, selective (partial) and total oxidation reactions, and enzymatic type reactions The book also touches heavily on the biomass applications of metal oxide catalysts and environmentally related/depollution reactions such as COVs elimination, DeNOx, and DeSOx. Finally, the book also deals with future trends and prospects in metal oxide-based heterogeneous catalysis. - Presents case studies in each chapter that provide a focus on the industrial applications - Includes fundamentals, key theories and practical applications of metal oxide-based heterogeneous catalysis in one comprehensive resource - Edited, and contributed, by leading experts who provide perspectives on synthesis, characterization and applications
Nanomaterials via Single-Source Precursors: Synthesis, Processing and Applications presents recent results and overviews of synthesis, processing, characterization and applications of advanced materials for energy, electronics, biomedicine, sensors and aerospace. A variety of processing methods (vapor, liquid and solid-state) are covered, along with materials, including metals, oxides, semiconductor, sulfides, selenides, nitrides, and carbon-based materials. Production of quantum dots, nanoparticles, thin films and composites are described by a collection of international experts. Given the ability to customize the phase, morphology, and properties of target materials, this "rational approach to synthesis and processing is a disruptive technology for electronic, energy, structural and biomedical (nano)materials and devices. The use of single-source chemical precursors for materials processing technology allows for intimate elemental mixing and hence production of complex materials at temperatures well below traditional physical methods and those involving direct combination of elements. The use of lower temperatures enables thin-film deposition on lightweight polymer substrates and reduces damage to complex devices structures such as used in power, electronics and sensors. - Discusses new approaches to synthesis or single-source precursors (SSPs) and the concept of rational design of materials - Includes materials processing of SSPs in the design of new materials and novel devices - Provides comprehensive coverage of the subject (materials science and chemistry) as related to SSPs and the range of potential applications
Carbon-Based Metal Free Catalysts: Preparation, Structural and Morphological Property and Application covers the different aspects of carbon-based metal free catalysts, including the fabrication of catalysts from natural sources and carbon allotropes, their manufacturing and design, characterization techniques, and applications. Special features in the book include illustrations and tables which summarize up-to-date information on research carried out on manufacturing, design, characterization and applications of metal free catalysts. This book assembles the information and knowledge on metal free catalysts and emphasizes the concept of green technology in the field of manufacturing and design. It is an ideal reference source for lecturers, students, researchers and industrialists working in the field of new catalyst development, especially polymer composites and is a valuable reference book handbook for teaching, learning, and research. - Describes the design on metal-free catalysts - Includes manufacturing technique of carbon-based metal free catalysts - Lists applications of carbon-based metal free catalysts - Discusses the characterization of carbon-based metal free catalysts
Fossil fuels constitute 86% of global energy consumption. Even though fossil fuels have satisfied our energy needs for decades, they are non-renewable source of energy, and burning of fossil fuels is detrimental for the environment. Mining and extraction release toxic and heavy metals in the environment. The burning of fossil fuels release greenhouse carbon dioxide, SO2, NOX and volatile organic compounds into the atmosphere. Hence, the development of non-fossil fuel based alternative sources of energy is a logical solution to address these concerns. This thesis work primarily focused on design, development and understanding the chemistry of two-dimensional (2D) layered materials, particularly transition metal oxides, birnessite and lithium cobalt oxide as catalytic materials for the conversion of renewable energy into fuels and. In order to accomplish this, we principally studied the energy intensive oxygen evolution reaction (OER) in water splitting, and Fischer-Tropsch synthesis (FTS) to generate synthetic fuels. Birnessite is a 2D layered manganese dioxide material with intercalated Lewis cations and water molecules. Birnessites have been extensively investigated for their catalytic activity towards oxygen evolution reaction. In this work, we studied the influence of interstitial hydration structure on the catalytic efficiency of birnessite towards OER. The results of this study facilitated the development of upgraded, low-cost and, earth abundant catalyst for the OER. We demonstrated that the layered materials constructed from the same batch of nanosheets, but with different interlayer hydration structure exhibited significant differences in catalytic activity for chemical and electrochemical water oxidation. The dominant factor in these differences was the enhancement of relevant water fluctuations due to geometric frustration leading to enhanced electron transfer rate in the oxidation step of water splitting. Furthermore, lithium cobalt oxide (LiCoO2) and Co-doped birnessite were explored for their competence as precatalysts for Fischer-Tropsch synthesis (FTS). FTS is a commercial technology that allows converting synthesis gas, a mixture of CO and H2, into fuels and chemicals. This process is fundamentally important in the reduction of fossil fuel dependency for the energy needs. It has a great potential for generating synthetic fuels from renewable sources, such as biomass, after its gasification into synthesis gas. The synthetic fuels produced via this technology have a lower local environmental impact as compared to the conventional fuel, since it is practically free of sulfur and nitrogen impurities and yields lower exhaust emissions of hydrocarbons. The present study focused on the use of cobalt-based catalysts for the production of small to medium chain hydrocarbons (paraffins and olefins). In particular, the correlation between product selectivity and varying catalyst properties and reaction parameters was studied. In-situ studies revealed that LiCoO2 was reduced to metastable Co(hcp) and Co(fcc) nanoparticles during the activation process, providing a high surface area medium for the adsorption and hydrogenation of CO. The catalyst exhibited a high %CO conversion with small to medium chain hydrocarbon products (C2-C7). Co-doped birnessited was reduced to Co(hcp) and MnO(ccp) phases during the activation step of the FTS reaction. MnO provided an excellent medium for the dispersion and stabilization of the cobalt nanoparticles to catalyze CO-hydrogenation. Lower olefins and paraffins (C2-C4) were selectively synthesized in conjunction with low CO2 production and methane selectivity. These studies suggested that transition metal oxide based layered heterogeneous catalysts are capable of producing chemicals and fuels directly from H2-rich synthesis gas. This gas-to-chemicals process can greatly reduce CO2 emissions, thereby contributing to the mitigation of climate change and the energy needs of the future generations.
With its two-volume structure, this handbook and ready reference allows for comprehensive coverage of both characterization and applications, while uniform editing throughout ensures that the structure remains consistent. The result is an up-to-date review of metal oxides in catalysis. The first volume covers a range of techniques that are used to characterize oxides, with each chapter written by an expert in the field. Volume 2 goes on to cover the use of metal oxides in catalytic reactions. For all chemists and engineers working in the field of heterogeneous catalysis.
Homogeneous catalysis is an important strategy for the synthesis of high-valued chemicals. L. Brandsma has carefully selected and checked the experimental procedures illustrating the catalytic use of copper, nickel, and palladium compounds in organic synthesis. All procedures are on a preparative scale, make economic use of solvents and catalysts, avoid toxic substances and have high yields.
