RESUMEN
Platinum nanoparticle has been supported on the tubular type titanium oxide using incipient wetness method employing H2PtCl6 as a precursor, where the loading was controlled to 4 wt%. The result of transmission electron micrographs of the sample showed the formation of Pt nanoparticles inside the tubule. The distribution of the particle size was found to be bimodal at ca. 1-2 nm and 5-6 nm, respectively. The former size was limited due to the inner diameter of the nanotubule. The particle size obtained from the hydrogen chemisorption, 1.24 H/Pt ratio was nearly 1 nm assuming spherical particle geometry, which was consistent with the formation of the Pt particle of 1-2 nm. The result suggested that there was no pore blockage for hydrogen since hydrogen can diffuse inside the channel through adsorption-diffusion-desorption on the Pt nanoparticle where the one dimensional channel was blocked with the particle itself.
RESUMEN
CO2 adsorption measurement at 273 K was employed to see if the porous material has either micropore or mesopore dominantly. The adsorption isotherm of CO2 on microporous solid such as zeolite A and Y was the typical Langmuir type while on SBA-15, silica gel and polymer, the adsorption isotherm was proportional to the applied pressure, following the Henry's law. Such distinctive difference between the adsorption isotherms provided the reasonable basis to discriminate the pore characteristics otherwise it was difficult to obtain it. Also, it was possible to get the surface property of polymer due to the pretreatment using CO2 adsorption measurement at 273 K while the N2 adsorption isotherm measurement at 77 K did not give the meaningful data.
RESUMEN
As a potential adsorbent for humidity control, the mesoporous silica, SBA-15, with various pore sizes that was synthesized hydrothermally at different temperatures was examined by measuring the rate of water adsorption under ambient condition, 2.53 kPa H2O and 30 degrees C. The adsorption saturation quantity and the diffusion coefficient of water were changed consistently with the micropore fraction in SBA-15 obtained from the t-plot method. The diffusion of water into the SBA-15 was very similar to that on either zeolite A or Y because of the presence of complimentary pore.
RESUMEN
Magnesium ion exchanged zeolite A was subject to the measurement of the temperature programmed desorption of NH3 to explore the possibility of the potential hydrogen carrier. The result suggested that the Mg supported NaA zeolite released a significant amount of ammonia corresponding to 1.4 Hwt% hydrogen at around 373 K. Under the same condition after the NH3 adsorption at ambient temperature, the MgCl2 sample released 1.0 Hwt% hydrogen at around 340 K. The present work suggests that the Mg supported zeolite can also be utilized as hydrogen carrier.