Ru/ZrO2 Catalysts

Development of Ceria-Supported Ruthenium Catalysts Effective for Various Synthetic Reactions

“…This band disappeared after the reaction and regenerated by the recalcination [42,44,48]. Although the distinct band due to ruthenium oxo species was not recognized on Ru/ZrO 2 in the present studies, the formation of reactive ruthenium-oxygen species has been proposed for the ZrO 2 -supported ruthenium catalyst [29,49]. On the other hand, there were no signs of oxo species for ruthenium catalysts supported on the other oxides [42,44,48].…”

Recyclable Solid Ruthenium Catalysts Supported on Metal Oxides for the Addition of Carboxylic Acids to Terminal Alkynes

“…[32] Although such a distinct peak was not recognized for Ru/ZrO 2 , the formation of similar ruthenium-oxygen species has also been proposed for the zirconia-supported catalyst. [33] There were no signs of oxo species for ruthenium catalysts supported on As demonstrated above, the catalytic activity of Ru/CeO 2 gradually decreased during repeated uses. In the present case, the gradual loss of surface chloride species shown in the XPS study would not be a major reason: The addition of NH 4 Cl (1 to 4 equivalents to Ru species) did not improve the activity of recycled catalysts, although the addition of NH 4 Cl significantly promoted the reaction by the catalysts prepared using chlorine-free Ru sources (see Table 2, entries 5 and 6).…”

Insight into the nature of active redox sites in Ru-containing hydroxyapatite by DRIFT spectroscopy

“…Although the infrared spectra were rather complex due to changes in the oxidation state of Ru induced by CO adsorption at room temperature and the concomitant evolution of CO 2 , interpretation of the spectra is supported by the abundant information available in the literature on various supported Ru-containing catalysts [20,[40][41][42]44,51] in all catalysts. The oxidation state of the Ru in the Ru n+ -oxide phase should be 3+, because the Ru + and Ru 2+ oxides are unstable, and the presence of Ru 4+ in the as-prepared material could be excluded.…”

“…5). The band at 2049 cm −1 in the as-prepared sample might be assigned to a HF 2 band of type III (di)carbonyls [41] or to monocarbonyl species (Ru n+ CO) [20].…”

“…The characteristic absorption bands corresponding to each feature appear commonly at 2060-2000 cm −1 (LF), 2160-2120 cm −1 (HF 1 ), at 2110-2060 cm −1 (HF 2 ) [40]. For example, the band at 2135 cm −1 (HF 1 ) that is typically associated with a component at 2055 cm −1 (HF 2 ) was assigned to the asymmetric and symmetric stretching of a Ru 3+ (CO) 2 species [41], whereas the bands at 2070 (HF 2 ) and 2004 cm −1 (LF) were assigned to those of a Ru 2+ (CO) 2 species on oxidized Ru/ZrO 2 . The bands at 2142 and 2084 cm −1 were assigned to Ru n+ (CO) 3 multicarbonyls on oxidized Ru/TiO 2 , a part of the band at 2084 cm −1 to Ru n+ -CO monocarbonyl, and the band at 2036 cm −1 to ionic dicarbonyls [40].…”