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Preparation and Characterization of Transitional Alumina Obtained through Ammonia Treatment
Yan Liu,Litao Jia,Bo Hou,Debao Li 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.12
In this study, different aluminas were obtained by precipitating Al(NO3)3·9H2O with different concentration of aqueous solution of ammonium carbonate. The obtained aluminas were treated by 50 (vol/vol) % ammonia via low temperature immersing and high temperature hydrothermal treatment, respectively, then, the treated aluminas were calcined again. The crystal types, morphology, textural properties, and pore distribution of the original alumina, ammonia-treated alumina, and the second calcined alumina were studied by characterizations of X-ray diffraction, thermogravimetric analyses, nuclear magnetic resonance, Brunauer-Emmett-Teller (BET), transmission electron microscopy, and so on. Several modified aluminas with specific morphology, desired pore structure, and pure crystal types were obtained, which can be used in some specific industrial application.
YONG DING,SONGYUAN DAI,Litao Jia,YANMEI MA,ZHAOQIAN LI,CHANGNENG ZHANG,JIANXI YAO,LIE MO,LINHUA HU,BING ZHANG,LING JIANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.5
The sub-microspheres play multiple roles in enhancing dye adsorption and light-scattering toimprove the performance of dye-sensitized solar cells (DSSCs). In this work, the well-de¯ned TiO 2sub-microspheres with anatase granular-like nanocrystals are prepared in high yield by com-bining hydrolytic process with solvothermal treatment. Scanning electron microscopy (SEM) andtransmission electron microscopy (TEM) results indicated that plenty of rhombic nanoparticleswith ? 18 nm diameter having mutual contacts to neighboring nanoparticles were densely self-assembled into sub-microspheres, and abundant mesopores existed in the whole sub-microsphereswith superior light scattering ability. The appropriate pore diameter and relatively high speci¯csurface area of the as-obtained sub-microsphere result in a higher dye adsorption. As expected, byusing the sub-microspheres as a scattering layer, a higher photovoltaic conversion e±ciency of10.15% is obtained for DSSCs.
Yuelun Wang,Bo Hou,Jiangang Chen,Litao Jia,Debao Li,Yuhan Sun 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3
Co/SiO2 catalysts were prepared by sol-gel method with varied en (ethylenediamine)/Co molar ratios under the same pH. Their physical-chemical properties were compared with those prepared with similar en/Co molar ratios at natural pH or without adding ethylenediamine. Regardless of pH, the catalysts prepared using ethylenediamine possessed high microporosity, which led to a better selectivity to C5-18 hydrocarbons, versus the catalyst possessing higher mesoporosity which showed slightly higher C18+ selectivity. As enough positions in the coordination sphere were blocked by ethanediamine ligands, the formation of cobalt silicate disfavored for (en/Co=2) catalysts, which resulted in the higher activity in FT reaction. Whereas the catalysts prepared with lower or higher en/Co molar ratio both showed lower activity due to the formation of [(SiO)Co(en)(EtOH)3] species or the electronic adsorption of cobalt complexes in the negatively charged silica surface, respectively. However, for the catalyst without using ethylenediamine, the lowest activity and the highest CH4 selectivity obtained due to its much lower reducibility.