20 research outputs found

    Deactivation Behavior of Supported Gold Palladium Nanoalloy Catalysts during the Selective Oxidation of Benzyl Alcohol in a Micropacked Bed Reactor

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    Highly active, supported Au–Pd catalysts have been tested for catalyzing benzyl alcohol oxidation in a silicon-glass micropacked bed reactor. The effects of Au–Pd composition and anion content during catalyst preparation on catalyst deactivation were studied, and a relationship between the deactivation rate and the amount of Cl– and Au used in the catalyst formulation was found. While Au aids in enhancing the selectivity to the desired product and the Cl– ions help the formation of uniform 1–2 nm nanoparticles, higher amounts of Au and Cl– become detrimental to the catalyst stability once a certain amount is exceeded. Loss of small (1–2 nm) metal nanoparticles was evident in all catalysts studied, accompanied by agglomeration and the formation of larger >10 nm particles. A secondary deactivation mechanism characterized by the formation of an amorphous surface film was observed via transmission electron microscopy in catalysts with high Cl– and Au and was associated with the detection of carbon species on the catalyst surface using Raman spectroscopy

    Sulfur promotion in Au/C catalyzed acetylene hydrochlorination

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    The formation of highly active and stable acetylene hydrochlorination catalysts is of great industrial importance. The successful replacement of the highly toxic mercuric chloride catalyst with gold has led to a flurry of research in this area. One key aspect, which led to the commercialization of the gold catalyst is the use of thiosulphate as a stabilizing ligand. This study investigates the use of a range of sulfur containing compounds as promoters for production of highly active Au/C catalysts. Promotion is observed across a range of metal sulfates, non‐metal sulfates, and sulfuric acid treatments. This observed enhancement can be optimized by careful consideration of either pre‐ or post‐treatments, concentration of dopants used, and modification of washing steps. Pre‐treatment of the carbon support with sulfuric acid (0.76 m) resulted in the most active Au/C in this series with an acetylene conversion of ≈70% at 200 °C

    Generating dialogical practices in mental health : experiences from southern Norway, 1998-2008

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    Published version of an article in the journal: Administration and Policy in Mental Health and Mental Health Services Research. Also available from the publisher at: http://dx.doi.org/10.1007/s10488-013-0479-3In Norway and many other countries, political guidelines prescribe the development of mental health strategies with both a service user's perspective and a treatment system established by the local authority. The development of new strategies frequently involves challenges regarding procedures and treatment as well as a view of knowledge and humanity. Dialogical practices might provide a solution for these challenges not only because of its procedures but also due to its attitudes toward service users. The aim is to explore the implementation of three dialogical practice programs in Southern Norway from 1998 to 2008 and to critically analyze and discuss the authors' experiences during the implementation process. Three different programs of dialogical practices were initiated, established, and evaluated within the framework of participatory action research. Sustainable changes succeed individually and organizationally when all participants engage as partners during the implementation of new mental health practices. Generating dialogic practice requires shared understanding of the Open Dialogue Approach (ODA) and collaboration between professional networks and among the leaders. Developing a collaboration area that includes service users in all stages of the projects was one of the essential implementation factors. Other factors involved a common vision of ODA by the leaders and the actors, similar experiences, and a culture of collaboration. However, ODA challenged traditional medical therapy and encountered obstacles to collaboration. Perhaps the best way of surmounting those obstacles is to practice ODA itself during the implementation process

    Soft power and soft disempowerment: Qatar, global sport and football’s 2022 World Cup finals

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    This paper examines the critical role of global sport within Qatar’s international strategy, most notably through the successful bid to stage the 2022 football World Cup. Our discussion draws particularly on interviews with key stakeholders in the Qatari sport system, as well as fieldwork in Qatar and the analysis of relevant documents and secondary materials. The paper is separated into five main parts. First, we set out our theoretical framework, which draws on the concepts of globalization and soft power; to assist in the analysis of Qatar’s engagement with global sport, we introduce the two further concepts of ‘glocal consciousness’ and ‘soft disempowerment’. Second, we provide the reader with background information on Qatar and Qatari sport. Third, we discuss three key themes that emerged mainly from our interviews on Qatar and global sport: exhibiting Qatar’s supremacies as a microstate; the pursuit of peace, security and integrity; and confronting national health crises. Fourth, we explore issues of soft disempowerment and reputational risk with regard to these three themes and, in particular, critical international comment surrounding Qatar’s hosting of the 2022 World Cup. Fifth, we conclude by arguing that Qatar’s soft disempowerment, although damaging in the short term, leaves the door open for the state to respond in a positive manner, regenerating its soft power capabilities in the process

    Cinnamyl alcohol oxidation using supported bimetallic Au-Pd nanoparticles: An investigation of autoxidation and catalysis

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    In this study, we examine autoxidation and its role on the catalytic aerobic oxidation of cinnamyl alcohol using supported AuPd nanoparticles. We further report the crucial role of reaction conditions in the reaction pathway. Close attention is paid to the mechanism of the formation of benzaldehyde, a by-product formed in large quantities from the process of autoxidation. The activity of the catalysts depends on the preparation method with different sizes of nanoparticles obtained by the two methods of preparation. The catalysts can inhibit the autoxidation process or the two processes, namely catalytic oxidation and autoxidation, can coexist. In the case of oxidation of cinnamyl alcohol, 0.5%(wt) Au–0.5%(wt) Pd/TiO2 catalysts prepared by various methods allow different product distributions to be obtained. The catalyst prepared by the sol-immobilisation method seems to prevent autoxidation, leaving the catalytic process dominant. Catalysts prepared by the impregnation method seem to enable both the catalytic process and autoxidation to occur at the same time. We show that using the optimum catalyst for this reaction, the autoxidation process can be mitigated

    Sulfur promotion in Au/C catalyzed acetylene hydrochlorination

    Get PDF
    The formation of highly active and stable acetylene hydrochlorination catalysts is of great industrial importance. The successful replacement of the highly toxic mercuric chloride catalyst with gold has led to a flurry of research in this area. One key aspect, which led to the commercialization of the gold catalyst is the use of thiosulphate as a stabilizing ligand. This study investigates the use of a range of sulfur containing compounds as promoters for production of highly active Au/C catalysts. Promotion is observed across a range of metal sulfates, non-metal sulfates, and sulfuric acid treatments. This observed enhancement can be optimized by careful consideration of either pre- or post-treatments, concentration of dopants used, and modification of washing steps. Pre-treatment of the carbon support with sulfuric acid (0.76 m) resulted in the most active Au/C in this series with an acetylene conversion of ≈70% at 200 °C
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