Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer...Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer of the photogenerated electrons from Si C to the Pd nanoparticles. As a result, the concentrated energetic electrons in the Pd nanoparticles can facilitate the cleavage of C–I or C–Br bonds, which normally requires high-temperature thermal processes. We show that the present Pd/Si C photocatalyst is capable of catalyzing the transformation of a large variety of aryl halides to their corresponding boronate esters under visible light irradiation, with excellent yields.展开更多
Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a h...Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure(ZSM-5/SiC).Characterizations of the ZSM-5/SiC by scanning electron microscopy,N2 sorption,and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity.Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst,which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate,a model molecule for biofuel.In comparison to the powder Pd@ZSM-5,the Pd@ZSM-5/SiC monolith catalyst shows more efficiency,which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure.The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.展开更多
In this paper the hydrogen and hydrocarbon gas sensing performance of the Pt/Catalysed TiO_2/SiC devices have been studied.The TiO_2 metal oxide thin films were catalytically modified employing Pt and Pd.The electrica...In this paper the hydrogen and hydrocarbon gas sensing performance of the Pt/Catalysed TiO_2/SiC devices have been studied.The TiO_2 metal oxide thin films were catalytically modified employing Pt and Pd.The electrical properties of the fabricated devices were studied by measuring their capacitance-voltage (C-V),conductance-voltage (G-V) and dynamic response characteristics.The sensor's response as a function of operating temperature (25℃to 700℃) and concentrations less than 1% of the analyte gases have been investigated.The sensitivity of the Pt catalysed TiO_2 sensor was found to be superior when compared to TiO_2 catalysed with Pd.A voltage shift of 3.2 V for 1% propene at 420℃and 2.8 V for 1% hydrogen at 250℃in an ambient containing synthetic air was recorded for the Pt catalysed TiO_2 sensor.The response of Pt catalysed TiO_2 sensor was found to be approximately 4 times larger when compared to the non catalysed counterpart.展开更多
基金supported by the National Natural Science Foudation of China(21473232,21673271,U1710112)
文摘Hierarchical Si C nanowire-supported Pd nanoparticles showed high photocatalytic activity for the C–X(X = Br, I) borylation of aryl halides at 30 °C. The Si C/Pd Mott-Schottky contact enhances the rapid transfer of the photogenerated electrons from Si C to the Pd nanoparticles. As a result, the concentrated energetic electrons in the Pd nanoparticles can facilitate the cleavage of C–I or C–Br bonds, which normally requires high-temperature thermal processes. We show that the present Pd/Si C photocatalyst is capable of catalyzing the transformation of a large variety of aryl halides to their corresponding boronate esters under visible light irradiation, with excellent yields.
文摘Conventional synthesis of monolith-supported zeolite catalysts is based on a hydrothermal strategy.Here,we report a solvent-free crystallization process to coat ZSM-5 zeolite crystals on a monolithic SiC foam with a honeycomb structure(ZSM-5/SiC).Characterizations of the ZSM-5/SiC by scanning electron microscopy,N2 sorption,and X-ray diffraction indicate that the zeolite sheath has been ideally coated on the surface of the SiC foam with high purity and crystallinity.Fixing Pd nanoparticles within the ZSM-5 zeolite crystals delivers a bifunctional Pd@ZSM-5/SiC catalyst,which exhibits high activity and selectivity toward diesel range paraffins in the hydrodeoxygenation of methyl oleate,a model molecule for biofuel.In comparison to the powder Pd@ZSM-5,the Pd@ZSM-5/SiC monolith catalyst shows more efficiency,which is attributed to the fast mass transfer and high heat conductivity on the honeycomb SiC structure.The durability test indicates that the Pd@ZSM-5/SiC catalyst is stable under the reaction and high-temperature regeneration conditions.
文摘In this paper the hydrogen and hydrocarbon gas sensing performance of the Pt/Catalysed TiO_2/SiC devices have been studied.The TiO_2 metal oxide thin films were catalytically modified employing Pt and Pd.The electrical properties of the fabricated devices were studied by measuring their capacitance-voltage (C-V),conductance-voltage (G-V) and dynamic response characteristics.The sensor's response as a function of operating temperature (25℃to 700℃) and concentrations less than 1% of the analyte gases have been investigated.The sensitivity of the Pt catalysed TiO_2 sensor was found to be superior when compared to TiO_2 catalysed with Pd.A voltage shift of 3.2 V for 1% propene at 420℃and 2.8 V for 1% hydrogen at 250℃in an ambient containing synthetic air was recorded for the Pt catalysed TiO_2 sensor.The response of Pt catalysed TiO_2 sensor was found to be approximately 4 times larger when compared to the non catalysed counterpart.
