https://nova.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:38517 2O₃ (possessing weak acid sites, 9.2 nm) and Ru/SiO₂ (absence of acid sites, 15.2 nm) were also prepared and examined. It was observed that a decrease in the Si/Al ratio of the support results in an increase in the yield of cyclohexane and a decrease in the yield of 2-methoxycyclohexanol in HDO of guaiacol. This data also discloses the influence of the concentration of acid sites on the deoxygenation of 2-methoxycyclohexanol. Both Ru/BEA and Ru/ZSM-5, with both possessing low Si/Al ratios, display a high activity for HDO for guaiacol, while only the Ru/BEA catalyst exhibits a high activity for HDO of biocrude oil. Catalyst characterisation (BET, NH₃-TPD and NH₃ and acetonitrile-d3-FTIR) shows that the Ru/BEA catalyst, with a low Si/Al ratio, not only possesses strong Brønsted acid sites but also contains extensive mesoporosity. Notably, these mesopores appear to facilitate the hydrogenation, deoxygenation, and ring-opening of large oxygenated and condensed-ring hydrocarbons in biocrude oil which then leads to a high yield of cycloalkanes. As expected, the Ru/Al₂O₃ and Ru/SiO₂ catalysts exhibit a high hydrogenation activity but a lower deoxygenation activity in the HDO of guaiacol and biocrude oil. These results suggest that the larger pore support, with strong Brønsted acid sites, engendered the HDO activity observed. The reaction pathway for the main components of biocrude oil was proposed based on the observed reaction product distribution.]]> Wed 20 Oct 2021 11:28:59 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:4409 Wed 11 Apr 2018 14:19:48 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36398 Mon 04 May 2020 13:53:00 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:39234 4⁺ cations in zeolites with Ru³⁺ ions, are employed for the hydrodeoxygenation of guaiacol. The performance results indicate ion-exchanged Ru zeolites, with extremely low Ru contents (~0.2 wt%), possess a high intrinsic HDO activity compared to the catalysts prepared by the incipient wetness impregnation method. On the basis of TEM, FTIR, XPS and TPD analysis, the NH₄⁺ ions in zeolite were substituted by Ru species, with metal particles entered the zeolite cages and finely dispersed on the support. These ion-exchanged Ru particles exhibit a strong electronic interaction with oxygen atoms of zeolite framework with a mixed Ru(0)-Ru(III) species observed in the reduced samples. In contrast, only Ru⁰ was detected in the reduced impregnated Ru/ZSM-5. The partial-reduced Ru species over the ion-exchanged Ru/ZSM-5 catalyst shows a high H₂ adsorption activity facilitating the hydrogenation of guaiacol to the saturated products (such as 2-methoxycyclohexanol). In addition, ion-exchanged Ru-ZSM-5 and Ru-BEA catalysts present a similar normalized cyclohexane formation rate (based on the concentration of acid sites), suggesting the acid sites play a pivotal role in the deoxygenation of 2-methoxycyclohexanol to cyclohexane.]]> Fri 27 May 2022 13:36:26 AEST ]]>