XPS and FTIR Study of Ru/Al₂O₃ and Ru/TiO₂ Catalysts:  Reduction Characteristics and Interaction with a Methane−Oxygen Mixture

Abstract

The oxidation state of alumina- and titania-supported Ru catalysts has been investigated as a function of reduction temperature, as well as by following the interaction with a methane−oxygen mixture at 773 and 973 K, employing XPS and FTIR techniques. It is found that the chemical behavior of Ru depends strongly on the material on which it is supported. Over Al2O3, ruthenium is incompletely reduced by treatment with hydrogen at 573 and 823 K, while oxidized Ru species are also detected following exposure of the catalyst to a methane−oxygen mixture at 773 and 973 K. In contrast, over TiO2, ruthenium is more easily reduced and is stabilized in its reduced state following hydrogen treatment at 823 K. During treatment with the methane−oxygen mixture, no reoxidation of Ru occurs. The interaction between Ru and TiO2, which inhibits the oxidation of ruthenium under conditions of partial oxidation of methane, is related to the unique ability of the Ru/TiO2 catalyst to promote the direct route of synthesis gas formation.

Pore Size Effect of Ru-Zn/ZrO2 Catalyst on Partial Hydrogenation of Benzene to Cyclohexene

“…将约 100 mg 样品装入样品管中, 在 Ar (99.999%) 气氛中于 473 K 下预处理 1 h, 然后降温至 298 K. 在该 温度下 CO (99.999%)脉冲进样 [24] , 至热导检测器(TCD) 检测的峰面积恒定为止, 即达到饱和吸附. 根据 CO 吸 附面积, 采用文献提供的方法计算 S Ru 和 Ru 的分散度, 假定吸附 CO 与金属 Ru 的化学计量比(CO/Ru)为 0.5, 且 Ru 的表面原子密度为 1.63×10 19 atoms•m -2 [33] . XPS 和 XAES 谱在美国 Perkin-Elmer PHI5000C 型 X 射线光电子能谱仪上测定.…”

Effect of Ru Species on N2O Decomposition over Ru/Al2O3 Catalysts

“…Figure 3 presents the XPS and the peak fitting results of Ru3d for the fresh and used Ru/Al2O3-H2, Ru/Al2O3-NaBH4 and Ru/Al2O3-air catalysts. The peaks at 280.2 and 285.0 eV were attributed to the 3d5/2 of metallic Ru and Ru 4+ species, respectively, and corresponding to the 3d3/2 binding energies at 284.4 (metallic Ru) and 289.1 eV (Ru 4+ ) [34,35]. The relative amounts of metallic Ru and Ru 4+ species were calculated from the areas of the fitted Gaussian-Lorentzian components of Ru3d shown in Table 1.…”

Preparation of Highly Dispersed Ni Catalysts for H₂ Production for Polymer Electrolyte Fuel Cells

“…However, strong metal-support interaction was frequently observed for catalysts with well-dispersed Ru particles, resulting in higher reduction temperature. In contrast to TiO2, Al2O3 apparently has a tendency to stabilize ruthenium in the ionic state and the reduction temperature sometimes exceeds 700 45) . RuO2 separated from the Rh _ Ni bimetallic system probably exists as fine particles on the catalyst surface and has a reduction peak around 400 .…”

“…This observation indicates that a part of the Ru separated during preparation. TPR of Ru/Al2O3 and Ru/MgO catalysts showed the Ru reduction peak occurred around 250 and 234 K, respectively 44), 45) . However, strong metal-support interaction was frequently observed for catalysts with well-dispersed Ru particles, resulting in higher reduction temperature.…”