| 1101. |
- Martin, Natalia Mihaela, 1984, et al.
(författare)
-
Catalytic hydrogenation of CO2 to methane over supported Pd, Rh and Ni catalysts
- 2017
-
Ingår i: Catalysis Science and Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 7:5, s. 1086-1094
-
Tidskriftsartikel (refereegranskat)abstract
- As a step in production of so-called electrofuels, ambient pressure CO2 hydrogenation has been investigated over different catalytic model systems based on metal particles (Pd, Rh and Ni) supported on various metal oxides (SiO2, Al2O3 and CeO2) and aluminosilicates (ZSM-5 and MCM-41) at different specific reactant ratios and temperatures between 150 and 450 degrees C. Catalytic activity and selectivity measurements in a flow reactor show that the highest CO2 conversion towards methane is obtained for the Rh/Al2O3 and Rh/CeO2 catalysts, followed by Ni/CeO2. Generally, the results suggest that both the support material and reaction conditions play an important role in the hydrogenation process. Further, in situ diffusive reflectance infrared Fourier transform spectroscopy reveals the intermediate species during transient CO2 hydrogenation over the Rh and Ni containing catalysts. Adsorption and dissociation of CO2 occurs over the Rh/Al2O3 catalyst in the presence of H-2, resulting in the formation of linear Rh-CO species, while formates and carbonates are formed over the Rh/CeO2 and Ni/CeO2 catalysts, likely at the metal-support interface.
|
|
| 1102. |
- Martin, Natalia M., et al.
(författare)
-
Structure-function relationship for CO2 methanation over ceria supported Rh and Ni catalysts under atmospheric pressure conditions
- 2019
-
Ingår i: Catalysis Science & Technology. - : Royal Society of Chemistry. - 2044-4753 .- 2044-4761. ; 9:7, s. 1644-1653
-
Tidskriftsartikel (refereegranskat)abstract
- In situ structural and chemical state characterization of Rh/CeO2 and Ni/CeO2 catalysts during atmospheric pressure CO2 methanation has been performed by a combined array of time-resolved analytical techniques including ambient-pressure X-ray photoelectron spectroscopy, high-energy X-ray diffraction and diffuse reflectance infrared Fourier transform spectroscopy. The ceria phase is partially reduced during the CO2 methanation and in particular Ce3+ species seem to facilitate activation of CO2 molecules. The activated CO2 molecules then react with atomic hydrogen provided from H-2 dissociation on Rh and Ni sites to form formate species. For the most active catalyst (Rh/CeO2), transmission electron microscopy measurements show that the Rh nanoparticles are small (average 4 nm, but with a long tail towards smaller particles) due to a strong interaction between Rh particles and the ceria phase. In contrast, larger nanoparticles were observed for the Ni/CeO2 catalyst (average 6 nm, with no crystallites below 5 nm found), suggesting a weaker interaction with the ceria phase. The higher selectivity towards methane of Rh/CeO2 is proposed to be due to the stronger metal-support interaction.
|
|
| 1103. |
- Marton, Z., et al.
(författare)
-
Mutations in the stereospecificity pocket and at the entrance of the active site of Candida antarctica lipase B enhancing enzyme enantioselectivity
- 2010
-
Ingår i: Journal of Molecular Catalysis B. - : Elsevier BV. - 1381-1177 .- 1873-3158. ; 65:1-4, s. 11-17
-
Tidskriftsartikel (refereegranskat)abstract
- Two different parts of Candida antarctica lipase B (stereospecificity pocket at the bottom of the active site and hydrophobic tunnel leading to the active site) were redesigned by single- or double-point mutations, in order to better control and improve enzyme enantioselectivity toward secondary alcohols. Single-point isosteric mutations of Ser47 and Thr42 situated in the stereospecificity pocket gave rise to variants with doubled enantioselectivity toward pentan-2-ol, in solid/gas reactor. Besides, the width and shape of the hydrophobic tunnel leading to the active site was modified by producing the following single-point mutants: Ile189Ala, Leu278Val and Ala282Leu. For each of these variants a significant modification of enantioselectivity was observed compared to wild-type enzyme, indicating that discrimination of the enantiomers by the enzyme could also arise from their different accessibilities from the enzyme surface to the catalytic site. (C) 2010 Elsevier B.V. All rights reserved.
|
|
| 1104. |
|
|
| 1105. |
- Meng, Jian-Qiao, et al.
(författare)
-
Imaging the Three-Dimensional Fermi-Surface Pairing near the Hidden-Order Transition in URu2Si2 Using Angle-Resolved Photoemission Spectroscopy
- 2013
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 111:12, s. 127002-
-
Tidskriftsartikel (refereegranskat)abstract
- We report angle-resolved photoemission spectroscopy experiments probing deep into the hidden-order state of URu2Si2, utilizing tunable photon energies with sufficient energy and momentum resolution to detect the near Fermi-surface (FS) behavior. Our results reveal (i) the full itinerancy of the 5f electrons, (ii) the crucial three-dimensional k-space nature of the FS and its critical nesting vectors, in good comparison with density-functional theory calculations, and (iii) the existence of hot-spot lines and pairing of states at the FS, leading to FS gapping in the hidden-order phase.
|
|
| 1106. |
|
|
| 1107. |
|
|
| 1108. |
|
|
| 1109. |
- Milani, Tommaso M., 1973, et al.
(författare)
-
Citizenship as status, habitus and acts: Language requirements and civic orientation in Sweden
- 2021
-
Ingår i: Citizenship Studies. - : Informa UK Limited. - 1362-1025 .- 1469-3593. ; 25:6, s. 756-772
-
Tidskriftsartikel (refereegranskat)abstract
- This article employs the notions of citizenship as status, habitus and acts as a framework through which to capture how sovereign power, disciplinary power and biopower intersect in the context of Sweden’s current management of migration. Through an analysis of policy and media debates, the article first illustrates how citizenship as status and sovereign power in Sweden have undergone a shift from actively endorsing multilingualism and cultural dialogue to requiring migrants to demonstrate knowledge of a particular language, Swedish, and what is constructed as a singular national culture and its values. The article then homes in on a particular Arabic-language course in civic orientation for newly arrived adult migrants in a large urban area. We illustrate how disciplinary power and biopower work by socializing a group of migrants into a specific habitus of Swedish values and norms. We also unveil the acts of resistance they perform in response.
|
|
| 1110. |
- Milani, Tommaso M., 1973, et al.
(författare)
-
Participation on whose terms? Applied linguistics, politics and social justice
- 2023
-
Ingår i: AFinLA Yearbook. - 2343-2608. ; 80
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this position paper is to engage with the focus of this yearbook on language and participation by revisiting some of the arguments advanced by the North American political philosopher Nancy Fraser, who theorized (1) the structural components that enable and/or constrain participation, and (2) the ways in which we can transform the status quo with a view to achieving a more just society. The paper begins by outlining Fraser’s main ideas; it then moves on to illustrate how this theoretical framework may help us shed light on the dilemmas and/or pitfalls of well-meaning initiatives that seek to enhance adult migrants’ participation. The empirical focus is on courses in civic orientation (samhällsorientering) for newly arrived adult migrants in Sweden. The paper ends with some reflections about the importance of a politically engaged applied linguistics.
|
|
