In the present study,a series of Ru/ZSM-5 catalysts with different pore-size distributions were prepared and investigated for NH3 synthesis.Our studies indicate that Ru/ZSM-5-Mic with micropore structure exhibits supe...In the present study,a series of Ru/ZSM-5 catalysts with different pore-size distributions were prepared and investigated for NH3 synthesis.Our studies indicate that Ru/ZSM-5-Mic with micropore structure exhibits superior NH3 synthesis rate,which is much higher than those of Ru/ZSM-5-Mac(with macroporous structure)and Ru/ZSM-5-Mes(with mesoporous structure)catalysts.A series of TPD experiments demonstrate that pore-size distributions play an important role in N2 adsorption and activation over Ru/ZSM-5.Moreover,the addition of La significantly promotes the NH3 synthesis performance over Ru/ZSM-5-Mic.Additionally,in situ DRIFTS studies indicate that the main intermediate species over Ru/ZSM-5-Mic are-NH2,and most of the surface hydrogen species desorb following the H2O-formation pathway.展开更多
2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated car...2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated carbon supported ruthenium(Ru/C) catalyst(with 5 wt% Ru loading), HMF was readily oxidized to FDCA in a high yield of 97.3% at 383 K and 1.0 MPa O_2 in the presence of Mg(OH)_2 as base additive. Ru/C was superior to Pt/C and Pd/C and also other supported Ru catalysts with similar sizes of metal nanoparticles(1–2 nm). The Ru/C catalysts were stable and recyclable, and their efficiency in the formation of FDCA increased with Ru loadings examined in the range of 0.5 wt%–5.0 wt%. Based on the kinetic studies including the effects of reaction time, reaction temperature, O_2 pressure, on the oxidation of HMF to FDCA on Ru/C, it was confirmed that the oxidation of HMF to FDCA proceeds involving the primary oxidation of HMF to 2,5-diformylfuran(DFF) intermediate, and its sequential oxidation to 5-formyl-2-furancarboxylic acid(FFCA) and ultimately to FDCA, in which the oxidation of FFCA to FDCA is the rate-determining step and dictates the overall formation rate of FDCA. This study provides directions towards efficient synthesis of FDCA from HMF, for example, by designing novel catalysts more efficient for the involved oxidation step of FFCA to FDCA.展开更多
基金Project supported by the National Natural Science Foundation of China(21972019)。
文摘In the present study,a series of Ru/ZSM-5 catalysts with different pore-size distributions were prepared and investigated for NH3 synthesis.Our studies indicate that Ru/ZSM-5-Mic with micropore structure exhibits superior NH3 synthesis rate,which is much higher than those of Ru/ZSM-5-Mac(with macroporous structure)and Ru/ZSM-5-Mes(with mesoporous structure)catalysts.A series of TPD experiments demonstrate that pore-size distributions play an important role in N2 adsorption and activation over Ru/ZSM-5.Moreover,the addition of La significantly promotes the NH3 synthesis performance over Ru/ZSM-5-Mic.Additionally,in situ DRIFTS studies indicate that the main intermediate species over Ru/ZSM-5-Mic are-NH2,and most of the surface hydrogen species desorb following the H2O-formation pathway.
基金supported by the National Natural Science Foundation of China(21373019,21433001,21690081)
文摘2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated carbon supported ruthenium(Ru/C) catalyst(with 5 wt% Ru loading), HMF was readily oxidized to FDCA in a high yield of 97.3% at 383 K and 1.0 MPa O_2 in the presence of Mg(OH)_2 as base additive. Ru/C was superior to Pt/C and Pd/C and also other supported Ru catalysts with similar sizes of metal nanoparticles(1–2 nm). The Ru/C catalysts were stable and recyclable, and their efficiency in the formation of FDCA increased with Ru loadings examined in the range of 0.5 wt%–5.0 wt%. Based on the kinetic studies including the effects of reaction time, reaction temperature, O_2 pressure, on the oxidation of HMF to FDCA on Ru/C, it was confirmed that the oxidation of HMF to FDCA proceeds involving the primary oxidation of HMF to 2,5-diformylfuran(DFF) intermediate, and its sequential oxidation to 5-formyl-2-furancarboxylic acid(FFCA) and ultimately to FDCA, in which the oxidation of FFCA to FDCA is the rate-determining step and dictates the overall formation rate of FDCA. This study provides directions towards efficient synthesis of FDCA from HMF, for example, by designing novel catalysts more efficient for the involved oxidation step of FFCA to FDCA.
