Porous oxides are used as a support of catalyst and membrane of gas separation, absorbant, host materials for hydrogen storage, etc. We used the aerosol process to prepare mesoporous oxides such as silica, alumina, titania, etc. Several porous oxide composites such as MgO/Al2O3, TiO2, V2O5/TiO2, and SiO2/TiO2 can be easily prepared by the aerosol process. Using a variety of organic templates initially in the spray soution makes it possible to produce high-ordered pores. Finally, metal oxides or composite particles have spherical shape and regular pore structure.
1) Catalytic oxidation of VOCs. Mesoporous V2O5/TiO2 particles were prepared by spray pyrolysis and applied to the catalytic oxidation of 1,2-dichlorobenzene (1,2-DCB). Catalytic activity of the V2O5/TiO2 particles depended strongly on the loading quantity of vanadia. It was confirmed that the 10 wt% V2O5/TiO2 particles prepared by spray pyrolysis had excellent activity for oxidation of 1,2-dichlorobenzene, particularly at temperatures below 300 ºC.
(2) Removal of waxing materials for the purification of packlitaxel from plant cell cultures. Spherical silica particles with various pore sizes were synthesized by spray pyrolysis using organic templates (CTAB, P123) and PS nanoparticles. The performance of the prepared silica was evaluated as an absorbent for the removal of impurities in the pre-purification processes of paclitaxel from plant-derivedcell cultures. From the evaluation of the prepared mesoporous silica particles as adsorbents for the removal of tar/waxy compounds, the adsorbent treatment was confirmed to be very helpful to increase the purity of paclitaxel after hexane precipitation. In terms of the removal performance of impurities from plant-derived cell culture, it was clear that the pore size rather than the surface area of the silica particles used is a much more important factor to determine the performance of the adsorbents. |
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(3) Dye-sensitized solar cell (RSC Adv., 2014,4, 10039 : DOI: 10.1039/c3ra47310) The light-conversion efficiency of dye-sensitized solar cells (DSSCs) was improved about 13.5% and 6.0% by dispersing a down-conversion phosphor (DCP) and an up-conversion phosphor (UCP) in a TiO2 layer, respectively. Also, further improvement in the efficiency could be achieved by forming DCP/UCP/TiO2 double composite layers (n = 8.88%), which is about 21% higher than that of the cell (n = 7.36%) without the phosphor dispersion. |
Carbon and Metal-Carbon Composites for Energy Storage and Electrochemical Separation.
- Direct Preparation of Porous Carbon with spherical morphology Via spray pyrolysis.
Porous carbon particles have various application areas such as absorbate, battery, hydrogen strage and fuel cell. The properties (size, microstructure, morphology, and porosity) of carbon particles or sheets should be adjusted in accordance with the application area. Carbon nano tube (CNT) or graphene is known to have a great potential as novel material applicable to various research fields. We are trying to design the porous carbon to have unique properties that make it deal for specific applications. Also, we have interest in the direct synthesis of the graphene sheet using the aerosol process. In the application as an electrode, carbon particles are frequently mixed with inorganic materials. So, the directly synthesis of carbon-inorganic composites has many advantages. makes it possible to easily control the electricahas a great potential
- Hollow and carbon nanosheet.
Related articles: (1) RSC Adv., 2016, 6, 1686 (2) DOI: 10.1039/C7RA01999H (Paper) RSC Adv., 2017, 7, 21314-21322
We synthesized porous carbons with different morphology using spray pyrolysis. A new and easy strategy to prepare hollow and nanosheet carbon powders via spray pyrolysis was developed. Accoriding to the electrochemical analysis, the hollow-structured carbon or the carbon nanosheet powders had higher ion-sorption capacitance compared with the spherical-shaped mesoporous carbon powders due to the increase of ion-accessible surface area. Thus, the spray pyrolysis developed makes it possible to design porous carbon that is potentially applicable as electrode materials for supercapacitor, battery and capacitive deionization.
- Functionalization of porous carbonn for Capacitive deionization (Coworker, Professor Choi's group in KNU)
The capacitivedeionization (CDI) process is very simple and economical separation technique to effectively remove ionic contaminants, passing salty water between two different electrodes with an charge. Then, negative and positive ions are moved toward the cathode and the anode side, respectively. Activated carbon powders have been used as the electrodes because of their high specific surface area, good chemical stability, high conductivity, benign to environment, rich source in nature, and lowcost. The CDI performance is determined by the electrode properties. Therefore, the development of new potential materials or the modification of ACP is necessaryto improve the CDI performance. We modify the surface of commercially-available activated carbon (AC) through the TiO2 coating andsulfonation. TiO2 coating on the AC surface was achieved by a sol-gel method and followed by the sulfonation using Tiron. The resulting powder was evaluated as a capacitive deionization (CDI) electrode and found to have improved CDI performance.
(1) Korean J. of Chem. Eng. 35 (1) (2018) 272–282. (2) Electrochim. Acta, 270 (2018) 543-551. (3) J. Electrochem. Soc. 159 (2012) E198-E203