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Frank S. Stone

Bio: Frank S. Stone is an academic researcher from University of Bath. The author has contributed to research in topic(s): Adsorption & Catalysis. The author has an hindex of 20, co-authored 56 publication(s) receiving 1513 citation(s). Previous affiliations of Frank S. Stone include Sapienza University of Rome & Keele University.
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Reference EntryDOI
A. Cimino1, Frank S. Stone2Institutions (2)
15 Mar 2008
Abstract: The sections in this article are Introduction Principles, Preparation, and Characterization Principles Preparation Characterization Bulk Composition and Structure Surface Composition Catalysis in the Context of Activity N2O Decomposition, CO Oxidation and H2D2 Equilibration Combustion of Hydrocarbons Perovskite Catalysts Hexa-Aluminate Catalysts Ceria-Containing Catalysts Catalysis in the Context of Selectivity Selective Oxidation Reactions Involving Dehydrogenation, Hydrogenation, and Reforming Catalysis in the Context of Surface Acidity and Basicity Dehydration of Alcohols on Ionic Solid Solutions Acid Catalysis by Aluminophosphates Conclusions Keywords: oxide solid solutions; transition metal ions; perovskites; scheelites

Journal ArticleDOI
Frank S. Stone1Institutions (1)
Abstract: Research developments recorded in the Journal of Catalysis over the past 40 years are reviewed. The journal was launched at a propitious time, as is made clear from the accounts presented of various topics newly introduced in the 1960s, which laid the foundation for achievements to come later, notably in catalysis by zeolites but also in reactions catalyzed by metals and transition metal oxides. The early years are shown to have been followed by a period marked by the skilled application of new experimental techniques, especially spectroscopic methods for catalyst characterization and chemisorption. Research in which ideas and methodology were interchanged between homogeneous and heterogeneous catalysis are also indicated. By the middle years perspectives in catalysis were becoming strongly influenced by concerns regarding oil reserves and care of the environment. Examples of fundamental research reflecting this are described. The article briefly digresses to recall the members who have composed the editorial team of the Journal of Catalysis over the past 40 years, all of them personally active in basic research and recognizable from their work as sympathetic to the drive for understanding catalysis at the molecular level. In a final section the survey returns to its leitmotiv when some research themes from recent years are collated, among them the continuing progress with zeolite-related catalysis, the search for improved enantioselective catalysts, and the application of techniques in theoretical chemistry to chart catalytic reaction mechanisms.

3 citations


Journal ArticleDOI
Alessandro Cimino1, Frank S. Stone1Institutions (1)
Abstract: This review traces the development of oxide solid solutions as catalysts from their first use in the 1960s to their current application in basic and applied research. Oxide solid solutions provide the means to control the properties of catalytically active ions in defined surface environments. When applied to transition metal (TM) ions, interaction with neighbors can be suppressed or progressively developed, depending on the concentration chosen for the active solute and the structure of the insulating matrix selected as solvent oxide. Simple examples are nickel, cobalt and chromium ions in MgO and MgAl 2 O 4 . The successful preparation of solid solutions demands a knowledge of the reactivity of solids and the behavior of crystal defects. This is exemplified in the methods described for preparing solid solutions of low and high specific surface area, respectively. Characterization receives detailed attention and the methods specific to oxide solid solutions are illustrated. Emphasis is placed on quantitative determination of surface composition for which X-ray photo-electron spectroscopy is the most widely applicable technique. The acidity and basicity of oxide solid solution surfaces is linked with coordinative unsaturation and this aspect of characterization involves adsorption calorimetry and infra-red spectroscopy. The account of oxide solid solutions as catalysts is divided into two parts. The first comprises studies where solid solutions have been used as model catalysts to identify and compare the catalytic properties of individual TM ions. For this purpose the catalysis of N 2 0 decomposition, CO oxidation and H 2 D 2 equilibration have long served as prototypical test reactions. These simple reactions enable issues such as the distinctive behavior of isolated ions, pairs and chains to be addressed and matrix effects to be explored. The motivation here is detailed understanding of catalysis on highly characterized microcrystalline oxides. The second catalytic part is broader in scope and focuses to a greater extent on the application of oxide solid solutions as catalysts for reactions of industrial interest. Combustion of hydrocarbons is a high-temperature reaction for which perovskite-structured solid solution catalysts are especially attractive since they accommodate a wide range of TM and main group ions in solid solution. A second sector covered is selective oxidation of hydrocarbons. Oxide solid solutions containing TM ions made an early entry as catalysts for alkene conversion and remained when interest switched to alkanes. The solid solution approach featured strongly in the search for methane coupling catalysts and currently contributes in a new guise in titanium silicalite. The acidity developed at solute sites is the source of activity for carbenium ion catalysis. SAPOs and McAPOs fall within the solid solution domain as covalently-bonded counterparts of ionic solid solutions. Finally, reduced solid solutions with phase-separated transition metal clusters are effective catalysts for reforming of alkanes.

6 citations


Journal ArticleDOI
Frank S. Stone1, David Waller1, David Waller2Institutions (2)
Abstract: Comparison is made between Cu–ZnO and alumina-supported Cu–ZnO as catalysts for the reverse water-gas shift (RWGS) reaction For both types of catalyst the Cu/Zn ratio has been varied between Cu-rich and Zn-rich compositions By applying X-ray diffractometry, X-ray line broadening, optical reflectance spectroscopy and other techniques the effects on the structural and physical properties of the hydroxycarbonate precursors, the calcined products and the ultimately derived catalysts are determined The presence of alumina decreases the crystallite size of the CuO and ZnO particles produced on calcination and at high Cu/Zn ratios increases the dispersion of copper in the final catalyst The activities of the catalysts for the RWGS reaction at 513K are compared and the most active are shown to be those which are Cu rich (Cu/Zn > 3) and contain alumina as support The activities of all the catalysts can be rationalized by referring the activity to unit surface area of copper metal

98 citations


Book ChapterDOI
Abstract: This review traces the development of oxide solid solutions as catalysts from their first use in the 1960s to their current application in basic and applied research. Oxide solid solutions provide the means to control the properties of catalytically active ions in defined surface environments. When applied to transition metal (TM) ions, interaction with neighbors can be suppressed or progressively developed, depending on the concentration chosen for the active solute and the structure of the insulating matrix selected as solvent oxide. Simple examples are nickel, cobalt and chromium ions in MgO and MgAl 2 O 4 . The successful preparation of solid solutions demands a knowledge of the reactivity of solids and the behavior of crystal defects. This is exemplified in the methods described for preparing solid solutions of low and high specific surface area, respectively. Characterization receives detailed attention and the methods specific to oxide solid solutions are illustrated. Emphasis is placed on quantitative determination of surface composition for which X-ray photo-electron spectroscopy is the most widely applicable technique. The acidity and basicity of oxide solid solution surfaces is linked with coordinative unsaturation and this aspect of characterization involves adsorption calorimetry and infra-red spectroscopy. The account of oxide solid solutions as catalysts is divided into two parts. The first comprises studies where solid solutions have been used as model catalysts to identify and compare the catalytic properties of individual TM ions. For this purpose the catalysis of N 2 0 decomposition, CO oxidation and H 2 D 2 equilibration have long served as prototypical test reactions. These simple reactions enable issues such as the distinctive behavior of isolated ions, pairs and chains to be addressed and matrix effects to be explored. The motivation here is detailed understanding of catalysis on highly characterized microcrystalline oxides. The second catalytic part is broader in scope and focuses to a greater extent on the application of oxide solid solutions as catalysts for reactions of industrial interest. Combustion of hydrocarbons is a high-temperature reaction for which perovskite-structured solid solution catalysts are especially attractive since they accommodate a wide range of TM and main group ions in solid solution. A second sector covered is selective oxidation of hydrocarbons. Oxide solid solutions containing TM ions made an early entry as catalysts for alkene conversion and remained when interest switched to alkanes. The solid solution approach featured strongly in the search for methane coupling catalysts and currently contributes in a new guise in titanium silicalite. The acidity developed at solute sites is the source of activity for carbenium ion catalysis. SAPOs and McAPOs fall within the solid solution domain as covalently-bonded counterparts of ionic solid solutions. Finally, reduced solid solutions with phase-separated transition metal clusters are effective catalysts for reforming of alkanes.

41 citations


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Journal ArticleDOI
Abstract: Cobalt, nickel and copper doped non-stoichiometric CdGa2O4 were synthesized via epoxide gel approach. Cubic spinel arrangement of undoped and doped samples was investigated from powder X-ray diffraction pattern and the complete structure analysis was done by using Raman spectroscopy. Additionally, cubic morphology of doped samples was analysed by FESEM images and elemental ratio of these samples have been obtained using Energy Dispersive spectrum (EDS). The oxidation state of doped metal ions was determined by optical and photoluminescence spectroscopy. The magnetic study of the doped samples showed the antiferromagnetic and ferromagnetic behaviour. The variation of band gap in transition metal doped samples has been favourably utilized for the photodegradation studies of aqueous solution of methylene blue and Rhodamine B dye.

Journal ArticleDOI
Abstract: This review discusses the thermodynamic and kinetic limitations that currently make the oxidative coupling of methane (OCM) industrially inviable. We analyze some promising strategies to overcome such limitations. We present a brief screening of the OCM catalysts, focusing on crucial aspects to improve their catalytic performance: methane and oxygen activation, acid-base properties, tuning electronic properties by doping, mixed oxides, and nanostructured materials. We especially discuss the current understanding of the Mn–Na2WO4/SiO2 catalyst by contrasting the well-consolidated literature against recent fast-developing in situ/operando studies. Finally, we analyze membrane reactors and monolith-supported catalysts as engineering approaches to manage thermal and kinetic OCM issues.

3 citations


Journal ArticleDOI
Abstract: High surface area cerium oxide was synthesized via the reverse microemulsion method and assessed for CO2 reduction to CO via reverse water gas shift. The resulted ceria nanoparticles (ca. 4 nm) were 100% selective to CO formation, while attaining a nearly equilibrium CO2 conversion at 600 °C. As compared to ceria synthesized by wet precipitation, the reverse microemulsion-synthesized ceria exhibited enhanced surface stability and a more stable catalytic performance (declining from 63% to 50% over 100 h on stream). No significant carbon formation was detected and a relatively small decline in conversion was related to the specific surface area reduction induced by the growth of ceria nanoparticles under the reaction conditions.

Journal ArticleDOI
Hongwei Zhang1, Lixiang Zhong2, Ismail Bin Samsudin1, Kazu Okumura3  +4 moreInstitutions (4)
Abstract: Nanoparticles are of interest in heterogeneous catalysis because of their excellent activity associated with atoms in a low coordination environment. However, their high reactivity becomes a drawback where selectivity is desired, compounded by their propensity towards agglomeration. Here, we show that stable subnanometric Rh particles can be prepared in a Mg-doped zeolite Beta based on the electrostatic interaction of the negatively charged zeolitic framework and the Rh3+ precursor. The Mg ions are incorporated into the zeolite framework whereas the Rh is located in the channels adjacent to the Mg. With only 0.27 and 0.5 wt.% Mg and Rh, respectively, the Rh/Mg-Beta catalysts were highly active with > 94 % selectivity for the hydrogenation of phenol to cyclohexanone, an important intermediate for the production of Nylon. Key to the selectivity is the formation of the C=O double bond early in the reaction sequence, aided by the basicity of the Mg-Beta support.


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Author's H-index: 20

No. of papers from the Author in previous years
YearPapers
20081
20033
20021
20001
19971
19962