Vanadium oxide nanotubes (VOx-NTs) have been synthesized by using n-butylamine as structuredirecting template and V2O5 as precursor under hydrothermal conditions. XRD, FTIR, SEM, TEM, BET and TG-DTA characterizations have been performed to both optimize the synthetic conditions and understand the growth mechanism of VOx-NTs. The results showed that open-ended VOx-NTs were obtained under the optimized conditions (hydrothermal temperature: 150―160°C, hydrothermal time: 5―7 d, the molar ratio of V2O5 to n-butylamine is 1:1) with diameters ranging from about 30 to 100 nm and several micrometers in length. The BET surface area and the desorption cumulative pore volume of pores of the as-synthesized sample were about 27.4609 m2/g and 0.191087 cm3/g, respectively. The result presents that the synthesis of VOx-NTs is controlled by the "rolling" mechanism and temperature is primary driving force for rolling.
Esterification of acrylic acid(AA) to produce AA esters has widespread application in the chemical industry. A series of water tolerant solid acid catalysts was prepared, and characterized by XRD, nitrogen adsorption, TGA-DTA, XPS, and ammonia adsorption FTIR. The effects of Si/Al ratio, zirconium sulfate(ZS) loading on HZSM-5 and calcination temperature on the esterification were investigated. When 20%(mass fraction) ZS is loaded on HZSM-5, the conversion of AA reaches 100%. XRD analysis indicates that ZS is highly dispersed on HZSM-5 because no crystalline structure assigned to ZS is found. Catalytic activity and hydrophobicity of ZS supported on HZSM-5 are higher compared with those of parent ZS or HZSM-5. Results show that this kind of novel catalysts is an efficient water tolerant solid acid catalyst for esterification reactions.
JIANG Ya-jieJUAN Joon ChingMENG Xiu-juanCAO Wei-liangYARMO Mohd AmbarZHANG Jing-chang
Rare earth ternary complexes Tb1-xEux(TTA)3Phen(x=0,0.25,0.5,0.75,1.0)were synthesized and characterized by DTA-TG,XRD and infrared(IR).The photophysical properties of these complexes were studied in detail using ultraviolet absorption spectra and fluorescent spectra.Ultraviolet absorption showed that the energy absorption of the complexes mostly came from ligands.Infrared spectra of Tb1-xEux(TTA)3Phen complexes were similar to the pure complexes.TG curves proved that the complexes were stable.Tb3+ emission was almost quenched and the Eu3+ emission was enhanced by codoping the complexes.The Tb3+ ion acted as an energy transfer bridge that helped energy transfer from poly(N-vinylcar-bazole(PVK)to Eu3+.In addition,their PL and EL properties were systematically studied.
A series of nanosized Co/Zn/Mn/K composite catalysts for Fischer-Tropsch synthesis(FTS) were prepared by supercritical fluid drying(SCFD) method and common drying(CD) method.The nanosized cobalt-based catalysts were characterized by XRD,TEM and BET techniques.Their catalytic performances were tested in a slurry-bed reactor under FTS reaction conditions.The drying and crystallization were carried out simultaneously during SCFD,therefore,the catalysts prepared by SCFD method have ideal structure and show the FTS performance superior to the others prepared by CD method.The FTS activity and selectivity were improved via adding Zn,Mn and K promoters,and less CH4 and CO2 as well as higher yield of C5+ products were achieved.The optimal performance of a 92% CO conversion and a 65% C5+ product yield was obtained over a catalyst with the component of Co/Zn/Mn/K = 100/50/10/7.Furthermore,the catalytic performance was studied under the conditions of liquid-phase and supercritical phase slurry-bed,and C5+ product yield were 57.4% and 65.4%,respectively.In summary,better catalytic performance was obtained using the nanosized catalyst prepared by SCFD method under supercritical reaction conditions,resulting in higher conversion of CO,less CO2 byproduct,and higher yield of C5+ products.
Jingmiao Li Jingchang Zhang Runduo Zhang Weiliang Cao
