The effect of catalyst preparation on the performance of alumina-supported ruthenium catalysts II. The impact of residual chloride

Thermal Stability of Ru–Re NPs in H2 and O2 Atmosphere and Their Activity in VOCs Oxidation: Effect of Ru Precursor

“…Evidently, hydrogen uptake both on the mono-and the bi-metallic sample is significantly lower as compared to the Cl-free catalysts (Table 2). Our previous and literature data [24,29,34] evidenced that chlorine had a negative effect on the H 2 or CO chemisorption on the Ru-based catalysts prepared from RuCl 3 . However, opposite to the Cl-free catalysts, H 2 uptakes on the sintered Cl-containing samples are much higher than on the same samples reduced at 500 °C.…”

“…However, it must be considered that even under such conditions, chlorine was not completely eliminated from the catalyst surface. In many reports, it was found that it is very difficult to eliminate residual chlorine from the Ru/Al 2 O 3 catalysts based on metal chlorides [29,35]. Narita et al [36] reported that for the Ru/Al 2 O 3 catalysts derived from RuCl 3, •large amounts of chlorine remained on the catalyst surface after reduction at ~ 320 °C and chlorine was partitioned between the support and the metal.…”

Solvent-free Hydrodeoxygenation of γ-Nonalactone on Noble Metal Catalysts Supported on Zirconia

“…Thus, the amount of CH 4 obtained with Ru/ZrO 2 was much higher than with the other catalysts possibly due to a decarbonylation and methanation mechanism, as Ru metal favors decarbonylation [30,36,37]. The presence of residual Cl species has not been identified to interact with adsorbed CO species or affect their reactivity [31,33]. The amount of methane also increased with temperature, which is explained by Arrhenius's law, as the thermodynamics were not limiting the methanation reactions at our reaction conditions (calculated via HSC Chemistry 6 software, using reactions described by Gao et al [38]).…”

“…Ru, having the lowest atomic mass, was expected to present the greatest amount of surface atoms. However, its actual position in the graph likely resulted from the initial occupation of active sites by residual Cl species, which occluded chemisorption sites [31,33]. Nevertheless, taking the initial TOFs as a gage of the activity per surface active site, it appears that Ru's sites were the most active (1 s −1 ) and Rh's sites were the least active (0.2 s −1 ).…”

Μείωση εκπομπών ΝΟx από απαέρια του αναγεννητή μονάδας καταλυτικής πυρόλυσης (FCC) μη τη χρήση καταλυτικών προσθέτων

“…Παρά την οµοφωνία όσον αφορά την απόδοση της κορυφής χαµηλής συχνότητας σε γραµµικά ροφηµένο CO πάνω σε µεταλλικό Ru 154,160,169 , η απόδοση κορυφών υψηλής συχνότητας είναι πιο αµφισβητήσιµη 167 . Γενικά κορυφές στα 2135, 2075-2045, και 2004 cm -1 σχετίζονται συνήθως µε καρβονυλικά είδη στο ρουθήνιο 154,160,164,165,[169][170][171] Κύρια τάση έρευνας για την ανάπτυξη και βελτίωση των τεχνικών ICP-AES και ICP-MS αποτελεί σήµερα 181 η ανάλυση πολύ µικρών όγκων δείγµατος (λόγω ευρύτητας πεδίου εφαρµογών: ηµιαγωγοί, γεωλογία, διαχωρισµός ρευστών, κλινικές µετρήσεις κτλ). Αν και οι συµβατικοί εκνεφωτές µπορούν να χρησιµοποιηθούν σε ογκοµετρικές ροές < 1ml min -1 ο σχεδιασµός τους δεν εξασφαλίζει βέλτιστη λειτουργία σε αυτές τις συνθήκες.…”