In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption ch...In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption characterization technologies. The high-pressure hydrogen uptake performance was analyzed using standard Pressure-Composition-Temperature apparatus in order to study the pore size effects on hydrogen uptake. These as-obtained porous carbons showed different characteristics of pore size distribution as well as specific surface area. The results indicate that the most effective pores for adsorbing hydrogen depended on the storage pressure. These ultramicropores （0.65-0.85 nm） could be the most effective pores on excess H2 uptake at 1 bar, however, micropores （0.85-2 nm） would play a more important role in excess H2 uptake at higher pressure at 77 K. At room temperature, pore size effects on H2 uptake capacity were very weak. Both specific surface area and total pore volume play more important roles than pore size for H2 uptake at room temperature, which was clearly different from that at 77 K. For applications in future, the corncob-derived activated carbons can be more available than zeolite templated carbons at 77 K. Element doping enhanced hydrogen uptake could be main research direction for improving H2 uptake capacity at room temperature.展开更多
Employing 0.3 nm diameter single-walled carbon nanotubes（SWCNTs）as saturable absorbers,we demonstrate a passively mode-locked fiber laser operating at 1950 nm.The 0.3 nm diameter SWCNTs are prepared by pyrolyzing di...Employing 0.3 nm diameter single-walled carbon nanotubes（SWCNTs）as saturable absorbers,we demonstrate a passively mode-locked fiber laser operating at 1950 nm.The 0.3 nm diameter SWCNTs are prepared by pyrolyzing dipropylamine in the channels of zeolite crystals Mg APO-11（AEL）.The laser pumped by a 1550 nm laser source produces 972 fs pulses with a spectral width at half-maximum of 4.2 nm and a repetition rate of 21.05 MHz,an average output power of 2.3 mW corresponding to the maximum pump power of 420 mW with a 10%output coupler.展开更多
基金supported by the National High Technology Research and Development Program of China(863 Program)(2012AA053305)the International Cooperation Project from Ministry of Science and Technology of China(2010DFA64080)
文摘In this work, the morphologies and pore structures of a series of corncob-derived activated carbons and zeolite templated carbon with ultrahigh surface area were carefully investigated by SEM, HRTEM and N2-sorption characterization technologies. The high-pressure hydrogen uptake performance was analyzed using standard Pressure-Composition-Temperature apparatus in order to study the pore size effects on hydrogen uptake. These as-obtained porous carbons showed different characteristics of pore size distribution as well as specific surface area. The results indicate that the most effective pores for adsorbing hydrogen depended on the storage pressure. These ultramicropores （0.65-0.85 nm） could be the most effective pores on excess H2 uptake at 1 bar, however, micropores （0.85-2 nm） would play a more important role in excess H2 uptake at higher pressure at 77 K. At room temperature, pore size effects on H2 uptake capacity were very weak. Both specific surface area and total pore volume play more important roles than pore size for H2 uptake at room temperature, which was clearly different from that at 77 K. For applications in future, the corncob-derived activated carbons can be more available than zeolite templated carbons at 77 K. Element doping enhanced hydrogen uptake could be main research direction for improving H2 uptake capacity at room temperature.
基金supported by the National Natural Science Foundation of China(No.61275144)the Shenzhen Science and Technology Project(Nos.JCYJ20150525092941038 and JCYJ20140418091413577)
文摘Employing 0.3 nm diameter single-walled carbon nanotubes（SWCNTs）as saturable absorbers,we demonstrate a passively mode-locked fiber laser operating at 1950 nm.The 0.3 nm diameter SWCNTs are prepared by pyrolyzing dipropylamine in the channels of zeolite crystals Mg APO-11（AEL）.The laser pumped by a 1550 nm laser source produces 972 fs pulses with a spectral width at half-maximum of 4.2 nm and a repetition rate of 21.05 MHz,an average output power of 2.3 mW corresponding to the maximum pump power of 420 mW with a 10%output coupler.
