Ultrafine Ru species within confined space: An efficient adsorbent for ultra-deep desulfurization of benzene.

The ultra-deep adsorptive desulfurization (ppb level) of benzene remains a challenging subject with the need to construct efficient adsorbent systems. Herein, a kind of ruthenium-based adsorbent functionalized with bimetallic Ru-Al was rationally designed using Al2O3 as support (denoted as 0.8%Ru-1.2%Al/Al2O3). It was found that the co-anchoring of Ru and Al species endows the Ru-based adsorbent unique adsorption capability, which is able to completely eliminate sulfur compounds in benzene, and exhibiting a much higher breakthrough sulfur capacity than that of the 0.8%Ru/Al2O3. Remarkably, under the industrial experiment conditions, 0.8%Ru-1.2%Al/Al2O3 exhibited excellent long-term stability for more than 1200 h, showing the potential for industrial application. Various characterization techniques, including BET, XRD, SEM, TEM, TPD-MS, TPR and XPS, were used to investigate the correlation between the adsorption performance and the microstructure of the adsorbents. Over 0.8%Ru-1.2%Al/Al2O3, the ultra-thin aluminum additive is beneficial to improve the dispersion of Ru species, which therefore exhibits desirable desulfurization efficiency. Moreover, the enhanced performance is also correlated to the presence of the suitable Ru active centers generated from the selective coverage by Al species. It leads to an optimal exposure of the Ru active centers, which would facilitate the interaction of S-Ru and the improvement of the desulfurization activity.

High-performance palladium catalysts for the hydrogenation toward dibenzylbiotinmethylester: Effect of carbon support functionalization.

Different functionalized carbon materials were used as supports to prepare Pd/carbon catalysts (Pd/AC, Pd/AC-O, Pd/AC-Cl and Pd/AC-N). The results of various characterization techniques revealed that a substantial increase in the surface functional groups of the supports could influence the size of the Pd nanoparticles and the chemical states of the Pd species due to Pd-support interactions. During the hydrogenation reaction to synthesize dibenzylbiotinmethylester, the Pd/AC-N catalyst, based on a support that was treated with nitric acid (AC-N), provided a higher yield of dibenzylbiotinmethylester than the other catalysts. The increase in surface oxygen groups (mainly CO2-releasing groups) in the AC-N support was relevant to achieving selective hydrogenation. These groups can provide an efficient pathway for the reaction, which may be responsible for the high yield of dibenzylbiotinmethylester.

Design and preparation of a simple and effective palladium catalyst and the hydrogenation performance toward dibenzylbiotinmethylester.

A series of well-dispersed carbon supported Pd catalysts were prepared by a simple and effective method under mild conditions. The functionalized carbon supported Pd catalyst (Pd/AC-H) demonstrated a enhanced performance to original carbon supported Pd catalyst (Pd/AC) in the probe reaction hydrogenation of 3,4-(1',3'-Dibenzyl-2'-oxoimidazolido)-2-(4-carboxybutylidene)thiophane to dibenzylbiotinmethylester. The results of various characterization techniques revealed that the improvement of Pd dispersion on Pd/AC-H catalyst surface could be associated to the presence of abundant oxygen-containing groups available for anchorage. Furthermore, the role of the surface groups of carbon supports was indispensable since they could provide an efficient pathway for the reaction. The oxygen-containing groups located at the Pd-supports interface were able to adjust the strength of reactant adsorption/activation on the Pd active sites, which was responsible for the high yield of dibenzylbiotinmethylester.