Peter Dinka

Bio: Peter Dinka is an academic researcher from University of Notre Dame. The author has contributed to research in topics: Combustion & Catalysis. The author has an hindex of 7, co-authored 11 publications receiving 691 citations.

Solution combustion synthesis of nanomaterials

Abstract: Solution combustion (SC) is an effective method for synthesis of nano-size materials and it has been used for the production of a variety (currently more than 1000) of fine complex oxide powders for different advanced applications, including catalysts, fuel cells, and biotechnology. However, it is surprising that while essentially all of the studies on SC emphasize the characterization of the synthesized materials, little information is available on controlling combustion parameters and the reaction mechanisms. This paper is devoted to the analysis of the combustion parameters for different SC reaction modes. First, the conventional volume combustion synthesis mode, which involves uniform reaction solution preheating prior to self-ignition, is briefly discussed. Second, for the first time, results of detailed experimental studies on steady-state self-propagating mode of SC synthesis of nano-powders are presented. Finally, the so-called solution + impregnation combustion mode is considered. The relationship between combustion parameters and product microstructures are emphasized. These results are crucial not only from the application stand-point, but more importantly lead to methodological benefits, allowing application of the developed approaches to investigate steady state heterogeneous combustion waves in new classes of reaction systems.

Novel Approaches to Solution-Combustion Synthesis of Nanomaterials

Abstract: Solution-combustion is an attractive approach to synthesis of nanomaterials for a variety of appli- cations, including catalysts, fuel cells, and biotechnology. In this paper, several novel methods based on the combustion of a reactive solution are presented. These methods include self-propagating sol-gel combustion and combustion of impregnated inert and active supports. It was demonstrated that, based on the fundamental understanding of the considered combustion processes, a variety of extremely high surface area materials could be synthesized. The controlling process parameters are defined and discussed. Examples of materials synthe- sized by the above methods are presented. For the first time, a continuous technology for production of nano- powders by using the solution combustion approach is demonstrated.

In Situ Preparation of Oxide-Based Supported Catalysts by Solution Combustion Synthesis

Abstract: The oxide-based supported catalysts with high specific surface area (>200 m2/g) were produced in one step through combination of the impregnation and solution combustion synthesis approaches. As a model system, iron oxide was selected, which was loaded on different porous supports including α-Al2O3, γ-Al2O3, and ZrO2, as well as activated alumina. It was shown that for the former three cases the specific surface areas of the supported catalysts are about or below the surface areas of the support. However, for the activated Al2O3 this characteristic significantly increases compared to that of the support. It was demonstrated that the developed approach may be used to produce different types of oxide-based supported catalysts, including perovskites.

Novel Method for Synthesis of Nano-Materials: Combustion of Active Impregnated Layers†

Abstract: Nanomaterials with characteristic structural dimensions on the order of few nanometers (1–100 nm) attract wide attention owing to their unique properties. They found a variety of applications in different branches of science and industry including catalysis, micro and biotechnologies, energy storage and conversion devices, such as fuel cells. Different techniques have been developed for nanomaterial preparations, solid-state, wet-type and CVD methods, mechano-, plasmaand combustion synthesis. A combination of combustion and reactive solution approaches leads to socalled solution (aqueous) combustion synthesis (SCS) method. Typically SCS involves a self-sustained reaction in solutions of metal nitrates and different fuels, which can be classified based on their chemical structure, i.e. type of reactive groups (e.g. amino, hydroxyl, carboxyl) bonded to the hydrocarbon chain. The reaction between fuel and oxygen containing species provides high temperature rapid interaction. In selfsustained propagation mode after local initiation the combustion front steadily moves along the sol-gel media forming extremely fine solid products with tailored composition. Several distinctive features of SCS contribute to the unique properties of the synthesized products. First, the initial reaction media being a liquid solution allows mixing the reactants on the molecular level thus permitting precise and uniform formulation of the desired composition on nano scale. Second, the high combustion temperatures ensure the formation of the desired phase composition directly in SCS wave. This feature allows one to skip additional step, i.e. high-temperature product calcination, which typically follows the conventional sol-gel approach. Third, short process duration (seconds) and formation large amount of gases during SCS, inhibit solid particle size growth and favor synthesis of nano-size powders with high specific surface area. Forth, almost no external energy is required to produce materials, since SCS occurs owing solely to the self-sustained highly exothermic reactions. Finally, simple equipments are typically used for this process. A wide variety of nano-materials was synthesized by the SCS approach, including unique pigments and catalysts, materials for SOFC and lithium batteries, oxygen sensors and storages, novel dielectric and piezoelectric compositions. Recently we reported method for synthesis of high surface area supported catalysts by reactive solution impregnation to the inert porous solid support, followed by initiation of the combustion reaction in such complex heterogeneous media. An unusual effect was found. By using this, so-called Impregnated Support Combustion (ISC) method, materials with very high specific surface area (> 200 m/g) were synthesized. However, not every material can be obtained by above techniques. Many low exothermic systems, which allow synthesize of valuable compositions, do not provide self-sustained reaction mode. To overcome this obstacle a novel, so-called, Impregnated Active Layer Combustion (IALC) method was developed and described below. IALC allows not only one step high yield production of powders with high surface area but also suggests an approach for continuous synthesis of such materials.

Cobalt-catalyzed sulfate radical-based advanced oxidation: A review on heterogeneous catalysts and applications

Abstract: Recently sulfate radical-based advanced oxidation processes (SR-AOPs) attract increasing attention due to their capability and adaptability in decontamination. The couple of cobalt and peroxymonosulfate (PMS) is an efficient way to produce reactive sulfate radicals. This article reviews the state-of-the-art progress on various heterogeneous cobalt-based catalysts for PMS activation, including cobalt oxides, cobalt-ferrite and supported cobalt by diverse substrates. We summarize the intrinsic properties of these catalysts and their fundamental behaviors in PMS activation, as well as synthetic approaches. In addition, influencing factors and synergistic techniques of Co/PMS systems in organic degradation and possible environmental applications are also discussed. Finally, we propose perspectives on challenges related to cobalt-based catalysts, heterogeneous Co/PMS systems and their potential applications in practical environmental cleanup.

Combustion synthesis and nanomaterials

Abstract: The recent developments and trends in combustion science towards the synthesis of nanomaterials are discussed. Different modifications made to conventional combustion approaches for preparation of nanomaterials are critically analyzed. Special attention is paid to various applications of combustion synthesized nanosized products.

Solution Combustion Synthesis of Nanoscale Materials

Abstract: Solution combustion is an exciting phenomenon, which involves propagation of self-sustained exothermic reactions along an aqueous or sol–gel media. This process allows for the synthesis of a variety of nanoscale materials, including oxides, metals, alloys, and sulfides. This Review focuses on the analysis of new approaches and results in the field of solution combustion synthesis (SCS) obtained during recent years. Thermodynamics and kinetics of reactive solutions used in different chemical routes are considered, and the role of process parameters is discussed, emphasizing the chemical mechanisms that are responsible for rapid self-sustained combustion reactions. The basic principles for controlling the composition, structure, and nanostructure of SCS products, and routes to regulate the size and morphology of the nanoscale materials are also reviewed. Recently developed systems that lead to the formation of novel materials and unique structures (e.g., thin films and two-dimensional crystals) with unusual...

Perovskite Oxides: Preparation, Characterizations, and Applications in Heterogeneous Catalysis

Abstract: Perovskite oxides with formula ABO3 or A2BO4 are a very important class of functional materials that exhibit a range of stoichiometries and crystal structures. Because of the structural features, they could accommodate around 90% of the metallic natural elements of the Periodic Table that stand solely or partially at the A and/or B positions without destroying the matrix structure, offering a way of correlating solid state chemistry to catalytic properties. Moreover, their high thermal and hydrothermal stability enable them suitable catalytic materials either for gas or solid reactions carried out at high temperatures, or liquid reactions carried out at low temperatures. In this review, we addressed the preparation, characterization, and application of perovskite oxides in heterogeneous catalysis. Preparation is an important issue in catalysis by which materials with desired textural structure and physicochemical property could be achieved; characterization is the way to explore and understand the textura...