Selective ammonia oxidation over ZSM-5 zeolite: Impact of catalyst's support porosity and type of deposited iron species

[EN] In the presented studies an influence of different parameters, such as zeolite sample porosity, form of used iron source ([Fe-3(OAc)(6)O(H2O)(3)](+)oligocations or FeSO4 solutions) and method of iron species deposition (ion-exchange, impregnation), on the catalytic activity in the process of the selective catalytic oxidation of ammonia (NH3-SCO) was studied. Conventional and mesoporous ZSM-5 zeolites, obtained by desilication and modified with iron species, were analysed with respect to their textural, surface and crystalline properties (N-2-sorption, HRTEM, SEM, XRD) as well as the form of introduced Fe species (UV-vis-DRS). Ion-exchange with [Fe-3(OAc)(6)O (H2O)(3)](+) oligocations and impregnation with these oligocations and FeSO4 solutions were found as the most effective methods of the zeolite samples activation for NH3-SCO.This work was carried out in the frame of project No. 0670/IP3/2016/74 from the Polish Ministry of Science and Higher Education in the years 2016-2019. Part of the work was performed in the frame of project No. 2012/05/B/ST5/00269from the National Science Centre (Poland). U. D. acknowledges to the Spanish Government by the funding (MAT2017-82288-C2-1-P). The authors would like to acknowledge to Clariant Company for the providing of the HMFI zeolite material for the presented research.Borcuch, A.; Rutkowska, M.; Marzec, A.; Kowalczyk, A.; Michalik, M.; Moreno, J.; Díaz Morales, UM.... (2020). Selective ammonia oxidation over ZSM-5 zeolite: Impact of catalyst's support porosity and type of deposited iron species. Catalysis Today. 348:223-229. https://doi.org/10.1016/j.cattod.2019.08.054S223229348Weckhuysen, B. M., & Yu, J. (2015). Recent advances in zeolite chemistry and catalysis. Chemical Society Reviews, 44(20), 7022-7024. doi:10.1039/c5cs90100fVerboekend, D., & Pérez-Ramírez, J. (2011). Design of hierarchical zeolite catalysts by desilication. Catalysis Science & Technology, 1(6), 879. doi:10.1039/c1cy00150gRutkowska, M., Pacia, I., Basąg, S., Kowalczyk, A., Piwowarska, Z., Duda, M., … Chmielarz, L. (2017). Catalytic performance of commercial Cu-ZSM-5 zeolite modified by desilication in NH 3 -SCR and NH 3 -SCO processes. Microporous and Mesoporous Materials, 246, 193-206. doi:10.1016/j.micromeso.2017.03.017Góra-Marek, K., Brylewska, K., Tarach, K. A., Rutkowska, M., Jabłońska, M., Choi, M., & Chmielarz, L. (2015). IR studies of Fe modified ZSM-5 zeolites of diverse mesopore topologies in the terms of their catalytic performance in NH3-SCR and NH3-SCO processes. Applied Catalysis B: Environmental, 179, 589-598. doi:10.1016/j.apcatb.2015.05.053Macina, D., Piwowarska, Z., Góra-Marek, K., Tarach, K., Rutkowska, M., Girman, V., … Chmielarz, L. (2016). SBA-15 loaded with iron by various methods as catalyst for DeNOx process. Materials Research Bulletin, 78, 72-82. doi:10.1016/j.materresbull.2016.02.026Rutkowska, M., Duda, M., Macina, D., Górecka, S., Dębek, R., Moreno, J. M., … Chmielarz, L. (2019). Mesoporous Beta zeolite functionalisation with FexCry oligocations; catalytic activity in the NH3SCO process. Microporous and Mesoporous Materials, 278, 1-13. doi:10.1016/j.micromeso.2018.11.003Miller, J. T., Glusker, E., Peddi, R., Zheng, T., & Regalbuto, J. R. (1998). Catalysis Letters, 51(1/2), 15-22. doi:10.1023/a:1019072631175Kowalczyk, A., Borcuch, A., Michalik, M., Rutkowska, M., Gil, B., Sojka, Z., … Chmielarz, L. (2017). MCM-41 modified with transition metals by template ion-exchange method as catalysts for selective catalytic oxidation of ammonia to dinitrogen. Microporous and Mesoporous Materials, 240, 9-21. doi:10.1016/j.micromeso.2016.11.002Chmielarz, L., & Jabłońska, M. (2015). Advances in selective catalytic oxidation of ammonia to dinitrogen: a review. RSC Advances, 5(54), 43408-43431. doi:10.1039/c5ra03218kThommes, M., Kaneko, K., Neimark, A. V., Olivier, J. P., Rodriguez-Reinoso, F., Rouquerol, J., & Sing, K. S. W. (2015). Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report). Pure and Applied Chemistry, 87(9-10), 1051-1069. doi:10.1515/pac-2014-1117Qi, G., & Yang, R. T. (2005). Selective catalytic oxidation (SCO) of ammonia to nitrogen over Fe/ZSM-5 catalysts. Applied Catalysis A: General, 287(1), 25-33. doi:10.1016/j.apcata.2005.03.00

Enhanced Exchange And Reduced Magnetization of Gd in an Fe/Gd/Fe Trilayer

The exchange interaction of Gd adjacent to Fe has been characterized by transport measurements on a double spin valve with a Fe/Gd/Fe trilayer as the middle layer. Our measurements show that the ferromagnetism of the Gd is enhanced by the presence of the Fe, and it remains ferromagnetic over its Curie temperature up to a thickness no smaller than 1 nm adjacent to the Fe. This thickness is more than double what has been reported before. Additionally, the saturation magnetization of the thin Gd layer sandwiched in Fe was found to be half of its bulk value. This reduced magnetization does not seem to be related to the proximity of Fe but rather to the incomplete saturation of Gd even for very high field

Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution

Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

First sagittarius A* Event Horizon Telescope results. VI. Testing the black hole metric

Galaxie

Resolving the inner parsec of the blazar J1924-2914 with the event horizon telescope

Galaxie

A universal power-law prescription for variability from synthetic images of black hole accretion flows

Instrumentatio

Millimeter light curves of sagittarius A* observed during the 2017 Event Horizon Telescope campaign

Galaxie

First sagittarius A* Event Horizon Telescope results. IV. Variability, morphology, and black hole mass

Galaxie

First M87 Event Horizon Telescope results. IX.: detection of near-horizon circular polarization

Galaxie