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- Chaoquan, Hu, 1981, et al.
(författare)
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Catalytic hydrogenation of C=C and C=O in unsaturated fatty acid methyl esters
- 2014
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Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 4:8, s. 2427-2444
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Forskningsöversikt (refereegranskat)abstract
- Biodiesel derived from edible and non-edible oils has received much attention as a chemical feedstock or as a raw fuel alternative to the traditional diesel due to its renewability and biodegradability. However, the crude biodiesel containing large amounts of polyunsaturated fatty acid methyl esters (FAMEs) is susceptible to oxidation upon exposure to heat, light, and oxygen. Catalytic hydro-genation of biodiesel has been considered as a feasible and powerful technique to improve the oxidative stability of biodiesel and hence to provide stable raw materials for industrial applications. The catalytic hydrogenation of FAMEs is a complex process but basically consists of hydrogenation of C=C or C=O, depending on the desirable properties of final products. In this review, we summarize recent developments in hydrogenation of C=C and C=O in FAMEs with focus on catalysts, reaction mechanisms, and reactor conditions. The features of hydrogenation of FAMEs are generalized and the opportunities for future research in the field are outlined.
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| 2. |
- Heard, Christopher, 1988, et al.
(författare)
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Structural and Energetic Trends of Ethylene Hydrogenation over Transition Metal Surfaces
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:2, s. 995-1003
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Tidskriftsartikel (refereegranskat)abstract
- Density functional theory calculations are used to investigate the catalytic hydrogenation of ethylene to ethane over a wide range of transition metal (TM) surfaces. Assuming the Horuiti-Polanyi mechanism, the enthalpies of adsorption, surface diffusion, and hydrogenation barriers are examined over close-packed surfaces of Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au. Special attention is given to the effects of ethylene and hydrogen coverage on the reaction pathway and activation energies. The previously suggested importance of the balance between di-s and p adsorption modes is reinvestigated, and most metals are found to exhibit a preference for the p state. Hydrogen coverage is found to control the reactant stability and promote a surface distortion which facilitates the hydrogen addition reaction. For all TMs, the calculated activation energies are low and span a narrow range.
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| 3. |
- Siahrostami, Samira, 1982, et al.
(författare)
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Enabling direct H2O2 production through rational electrocatalyst design
- 2013
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 12:12, s. 1137-1143
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Tidskriftsartikel (refereegranskat)abstract
- Future generations require more efficient and localized processes for energy conversion and chemical synthesis. The continuous on-site production of hydrogen peroxide would provide an attractive alternative to the present state-of-the-art, which is based on the complex anthraquinone process. The electrochemical reduction of oxygen to hydrogen peroxide is a particularly promising means of achieving this aim. However, it would require active, selective and stable materials to catalyse the reaction. Although progress has been made in this respect, further improvements through the development of new electrocatalysts are needed. Using density functional theory calculations, we identify Pt-Hg as a promising candidate. Electrochemical measurements on Pt-Hg nanoparticles show more than an order of magnitude improvement in mass activity, that is, Ag-1 precious metal, for H2O2 production, over the best performing catalysts in the literature.
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