In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice...In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.展开更多
A new method for the fabrication of carbon aerogels is reported in this paper. Resorcinol and furfural were gelated in isopropanol with basic catalysts and then dried directly under isopropanol supercritical condition...A new method for the fabrication of carbon aerogels is reported in this paper. Resorcinol and furfural were gelated in isopropanol with basic catalysts and then dried directly under isopropanol supercritical condition, followed by carbonization under nitrogen atmosphere. The bulk densities of carbon aerogels obtained are in the range of 0.21g/cm3~0.27g/cm3 and the sizes of the interconnected carbon nano-particles are in the range of 20nm^30nm. All of the aerogel samples exhibit high BET surface areas in the range of 730m2/g^900m2/g. The bulk density, micro-pore volume, meso-pore volume and meso-pore diameter can be controlled by gelation conditions such as R/I ratio and R/C ratio.展开更多
The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding struct...The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding structural and textural properties by XRD, FTIR, nitrogen adsorption/desorption, thermal analysis and ESA experiments. Palladium supported MOF-5 catalyst has been prepared by adsorption inclusion method. The catalyst was activated by treatment with supercritical carbon dioxide （scCO2） followed by mild reduction with hydrogen solved in scCO2. The obtained catalyst is shown to be stable and active and shape selective in hydrogenation reactions of alkenes using supercritical carbon dioxide as reaction medium. The catalytic active Pd species are located inside the pores. Positive surface charging seems to prevent deposition of active species at the crystal surface of the MOF. The catalyst is long time stable and re-useably. These findings show the potential of porous MOFs for applications under supercritical conditons and resisted repeated pressuring to 120 bar at elevated temperature.展开更多
文摘In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.
基金The National Natural Science Foundation of China (No. 59973028), The Team Project of the Natural Science Foundation of Guangdong (No.[( )(20003038)]), and The Talent Training Program Foundation of the Higher Education Departmen
文摘A new method for the fabrication of carbon aerogels is reported in this paper. Resorcinol and furfural were gelated in isopropanol with basic catalysts and then dried directly under isopropanol supercritical condition, followed by carbonization under nitrogen atmosphere. The bulk densities of carbon aerogels obtained are in the range of 0.21g/cm3~0.27g/cm3 and the sizes of the interconnected carbon nano-particles are in the range of 20nm^30nm. All of the aerogel samples exhibit high BET surface areas in the range of 730m2/g^900m2/g. The bulk density, micro-pore volume, meso-pore volume and meso-pore diameter can be controlled by gelation conditions such as R/I ratio and R/C ratio.
文摘The metal-organic framework MO-5 has been synthesized by solvothermal method. Obtained material consists of nano-sized particle of ca. 100 nm size. The material has been physico-chemical characterized regarding structural and textural properties by XRD, FTIR, nitrogen adsorption/desorption, thermal analysis and ESA experiments. Palladium supported MOF-5 catalyst has been prepared by adsorption inclusion method. The catalyst was activated by treatment with supercritical carbon dioxide （scCO2） followed by mild reduction with hydrogen solved in scCO2. The obtained catalyst is shown to be stable and active and shape selective in hydrogenation reactions of alkenes using supercritical carbon dioxide as reaction medium. The catalytic active Pd species are located inside the pores. Positive surface charging seems to prevent deposition of active species at the crystal surface of the MOF. The catalyst is long time stable and re-useably. These findings show the potential of porous MOFs for applications under supercritical conditons and resisted repeated pressuring to 120 bar at elevated temperature.
