Silver nanoparticles prepared by the direct reduction of AgNO3 in aqueous solution were compacted into coins and used as the cathode for the electrocatalytic carboxylation of 1-phenethyl bromide with CO2. The influenc...Silver nanoparticles prepared by the direct reduction of AgNO3 in aqueous solution were compacted into coins and used as the cathode for the electrocatalytic carboxylation of 1-phenethyl bromide with CO2. The influences of the working electrode, charge, current density and temperature were investigated. Under optimized conditions, 98% yield of 2-phenylpropionic acid was obtained. The reaction was performed under very mild conditions and no added catalyst was required in the electrolyte. Yields that varied from moderate to excellent were also achieved with other benzyl bromides. This electrode has good stability and reusability, and the yield and selectivity of 2-phenylpropionic acid could be maintained during reuse for 10 times.展开更多
Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffracti...Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffraction,infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The valence state and distribution of elements in the obtained materials were examined using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy.Catalytic performance studies show that the cerium-doped NH_(2)-UiO-66 exhibits improved catalytic efficiency in the cycloaddition reaction of 1,2-butylene oxide and carbon dioxide than pure NH_(2)-UiO-66.Studies on the photoelectric properties indicate that the cerium-doped NH_(2)-UiO-66 catalyst possesses strong photocurrent response,low interfacial charge transfer resistance,narrow band gap,and low flat band potential.This work provides a new approach of synthesizing high-performance catalyst for photocatalytic CO_(2) cycloaddition.展开更多
The effects of EGR and ignition timing on engine emissions and combustion were studied through an experiment carried out on an air-guided GDI engine.The test results showed that the ignition timing significantly affec...The effects of EGR and ignition timing on engine emissions and combustion were studied through an experiment carried out on an air-guided GDI engine.The test results showed that the ignition timing significantly affected the GDI engine emissions,that the NOx emissions significantly reduced when the ignition timing was retarded,and that NOx emissions decreased with the EGR level increasement.A higher EGR rate could reduce CO emissions while the CO emissions were less affected by the ignition timing.The HC emissions decreased at a lower EGR rate.At 2500 r/min,an appropriate EGR rate could cut down CO emissions.The exhaust gas temperature could significantly decrease with improving the EGR rate,and the exhaust gas temperature at 2500 r/min was clearly higher than that at 1850 r/min.The nucleation mode particles increased clearly,the accumulation mode particle number decreased gradually with the increase of EGR rate,and the typical particle size of nucleation mode particle was in the range of 10–25 nm.展开更多
基金supported by the National Natural Science Foundation of China(21203066,21373090,21473060)~~
文摘Silver nanoparticles prepared by the direct reduction of AgNO3 in aqueous solution were compacted into coins and used as the cathode for the electrocatalytic carboxylation of 1-phenethyl bromide with CO2. The influences of the working electrode, charge, current density and temperature were investigated. Under optimized conditions, 98% yield of 2-phenylpropionic acid was obtained. The reaction was performed under very mild conditions and no added catalyst was required in the electrolyte. Yields that varied from moderate to excellent were also achieved with other benzyl bromides. This electrode has good stability and reusability, and the yield and selectivity of 2-phenylpropionic acid could be maintained during reuse for 10 times.
文摘Cerium-doped zirconium-based NH_(2)-UiO-66 nanoparticles were synthesized in ionic liquid 1-butyl-3-methylimidazolium acetate at room temperature.The crystal structure and morphology were studied using X-ray diffraction,infrared spectroscopy,scanning electron microscopy and transmission electron microscopy.The valence state and distribution of elements in the obtained materials were examined using X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy.Catalytic performance studies show that the cerium-doped NH_(2)-UiO-66 exhibits improved catalytic efficiency in the cycloaddition reaction of 1,2-butylene oxide and carbon dioxide than pure NH_(2)-UiO-66.Studies on the photoelectric properties indicate that the cerium-doped NH_(2)-UiO-66 catalyst possesses strong photocurrent response,low interfacial charge transfer resistance,narrow band gap,and low flat band potential.This work provides a new approach of synthesizing high-performance catalyst for photocatalytic CO_(2) cycloaddition.
基金supported by the China Postdoctoral Science Foundation(Grant No.2013M540251)the Liaoning Province Fund:PhD Start-upFund(Grant No.20111026)the National Natural Science Foundation of China(Grant No.51276079)
文摘The effects of EGR and ignition timing on engine emissions and combustion were studied through an experiment carried out on an air-guided GDI engine.The test results showed that the ignition timing significantly affected the GDI engine emissions,that the NOx emissions significantly reduced when the ignition timing was retarded,and that NOx emissions decreased with the EGR level increasement.A higher EGR rate could reduce CO emissions while the CO emissions were less affected by the ignition timing.The HC emissions decreased at a lower EGR rate.At 2500 r/min,an appropriate EGR rate could cut down CO emissions.The exhaust gas temperature could significantly decrease with improving the EGR rate,and the exhaust gas temperature at 2500 r/min was clearly higher than that at 1850 r/min.The nucleation mode particles increased clearly,the accumulation mode particle number decreased gradually with the increase of EGR rate,and the typical particle size of nucleation mode particle was in the range of 10–25 nm.
