Structure, stability and activity of RuS2 supported on alumina

Transition Metal Sulfide Catalysts for Petroleum Upgrading – Hydrodesulfurization Reactions

“…In this sense, when sulfiding at 773 K the signals at T < 573 K decreases in intensity, while those at T > 573 K are more defined, what suggests that a higher amount of pyrite-type structure is formed, in accordance with previous works (De los Reyes et al, 1991) and also confirmed by XRD data. A similar profile at high temperatures has been reported by other authors (Castillo-Villalón et al, 2008), i.e., the asymmetry of this band, which can be decomposed into two contributions, is due to a surface reduction followed by bulk reduction. Castillo-Villalón et al (Castillo-Villalón et al, 2008) have recently reported that in so far as the sulfidation temperature increases, the H2S evolving from species reduced at high temperature does, in detriment to some species that are reduced at low temperatures.…”

“…A similar profile at high temperatures has been reported by other authors (Castillo-Villalón et al, 2008), i.e., the asymmetry of this band, which can be decomposed into two contributions, is due to a surface reduction followed by bulk reduction. Castillo-Villalón et al (Castillo-Villalón et al, 2008) have recently reported that in so far as the sulfidation temperature increases, the H2S evolving from species reduced at high temperature does, in detriment to some species that are reduced at low temperatures. Thus, by increasing the sulfidation temperature, some ruthenium sulfided species found when sulfiding at 673 K, are transformed into more stable RuS2 species when sulfiding at 773 K and that is why catalysts sulfided at 773 K present these bands more intense.…”

“…In the second H2S removal, between 450 K and 570 K, the elimination of surface sulfur anions occurs. Some authors have found that this band tends to disappear by sulfiding at higher temperatures, suggesting that this band arises from the reduction of an amorphous or poorly crystallize RuS2 phase at low sulfiding temperatures (Castillo-Villalón et al, 2008) and also ascribed to the release of labile sulfur (CUS). Finally, at T > 573 K, the elimination of bulk sulfur of the RuS2-pyrite takes place leading to metallic ruthenium (Castillo-Villalón et al, 2008;De los Reyes et al, 1991).…”

Low-temperature synthesis of rhodium phosphide on alumina and investigation of its catalytic activity toward the hydrodesulfurization of thiophene

“…RuS2 for thiophene HDS [ 42]. Recentl y, it has been reported that particle size strongl y affects the crystallinit y of Pt nanoparticle s [43].…”

Synthesis of Highly Active Ruthenium Sulfide Hydrodesulfurization Catalysts: Effect of Hydrogen in the Activation Process

“…Despite of Pecoraro results, the recent studies reported for ruthenium sulfide catalysts barely have achieved activities similar to those of industrial catalyst and only a few have reached the activity reported by Pecoraro [5]. Many authors related the low ruthenium sulfide catalytic activity with low sulfuration levels and remaining of metallic ruthenium in the catalyst, associated with the use during the activation process of hydrogen which is a reduction agent [6,7,8], nevertheless the role of metallic ruthenium in the HDS reaction is not clear.…”