• Bulletin of the Korean Chemical Society
• /
• 제30권6호
• /
• pp.1349-1352
• /
• 2009

We report the results of the surface chemistry of deuterized ethanol exposed Zircaloy-4 (Zry-4) surfaces with various amount of $C_2D_5$OD exposures at 190 K. This system was examined with Auger electron spectroscopy (AES) and temperature programmed desorption (TPD) techniques. In TPD study, $D_2$ was evolved at two different desorption temperature regions accompanying with broad desorption background. The lower temperature feature at around 520 K showed first-order desorption kinetics. The high temperature desorption peak at around 650 K shifted to lower desorption temperature as the exposure of $C_2D_5$OD increased. The Zr(MNV) Auger peak shifted about 2.5 eV from 147 eV to lower electron energy followed by 300 L of $C_2D_5$OD dosing. This implies metallic zirconium was oxidized by deuterized ethanol adsorption. After stepwise annealing of the oxidized Zry-4 sample up to 843 K, the shifted Zr(MNV) peak was gradually shifted back to metallic zirconium peak position. After the sample was heated to 843 K, the oxygen content near the Zry-4 surface was recovered to clean surface level. The concentration of carbon, however, was not recovered by annealing the sample.

• 공업화학
• /
• 제5권1호
• /
• pp.1-15
• /
• 1994

승온열탈착기술(temperature-programmed desorption, TPD)은 촉매의 특성을 연구하는데 매우 유용한 실험방법이다. 일반적으로 상압하에서 수행되는 것이 대부분인데, 근래에 진공조건에서 분말상의 촉매에 대한 TPD실험을 통하여 매우 중요한 결과들이 많이 발표되고 있다. 본 논문에서는 진공하에서의 TPD실험결과의 해석 및 실험법이 간략하게 소개된다.

• 한국재료학회지
• /
• 제29권3호
• /
• pp.143-149
• /
• 2019

To develop flexible adsorbents for compact volatile organic compound (VOC) air purifiers, flexible as-spun zeolite fibers are prepared by an electrospinning method, and then zeolite particles are exposed as active sites for VOC (toluene) adsorption on the surface of the fibers by a thermal surface partial etching process. The breakthrough curves for the adsorption and temperature programmed desorption (TPD) curves of toluene over the flexible zeolite fibers is investigated as a function of the thermal etching temperature by gas chromatography (GC), and the adsorption/desorption characteristics improves with an increase in the thermal surface etching temperature. The effect of acidity on the flexible zeolite fibers for the removal of toluene is investigated as a function of the $SiO_2/Al_2O_3$ ratios of zeolites. The acidity of the flexible zeolite fibers with different $SiO_2/Al_2O_3$ ratios is measured by ammonia-temperature-programmed desorption ($NH_3-TPD$), and the adsorption/desorption characteristics are investigated by GC. The results of the toluene adsorption/desorption experiments confirm that a higher $SiO_2/Al_2O_3$ ratio of the flexible zeolite fibers creates a better toluene adsorption/desorption performance.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.216-216
• /
• 2012

The interaction of hydrogen with ZnO single crystal surfaces, ZnO (0001), ZnO (000-1), and ZnO (10-10) has been investigated using temperature programmed desorption (TPD) and X-ray photoelectron Spectroscopy (XPS) techniques. When the ZnO single crystal surfaces are exposed to atomic hydrogen at 200 K, all three surfaces show hydrogen desorption at 450 K. ZnO (0001) surface shows hydrogen desorption feature at ~260 K as the hydrogen exposure is increased. The ZnO (10-10) surface shows low-temperature desorption feature first and the high-temperature desorption feature appears as the hydrogen exposure increases. The ZnO (000-1) surface does not show any lower temperature hydrogen desorption. We will report the adsorption configuration of hydrogen atoms on ZnO single crystal surfaces with different surfaces structures.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.268-268
• /
• 2012

Adsorption and desorption of toluene from bare and $TiO_2$-coated silica with a mean pore size of 15 nm was studied using breakthrough curves and temperature programmed desorption. Thicknesses of $TiO_2$ films prepared by atomic layer deposition on silica were < 2 nm, and ~ 5 nm, respectively. For toluene adsorption, both dry and humid conditions were used. $TiO_2$-thin film significantly improved toluene adsorption capacity of silica under dry condition, whereas desorption of toluene from the surface as a consequence of displacement by water vapor was more pronounced for $TiO_2$-coated samples with respect to the result of bare ones. In the TPD experiments, silica with a thinner $TiO_2$ film (thickness < 2 nm) showed the highest reactivity for toluene oxidation to $CO_2$ in the absence and presence of water. We show that the toluene adsorption and oxidation reactivity of silica can be controlled by varying thickness of $TiO_2$ thin films.

• Bulletin of the Korean Chemical Society
• /
• 제32권5호
• /
• pp.1559-1563
• /
• 2011

Thermal hydrogenation of phenylacetylene (PA, $C_8H_6$) to styrene ($C_8H_8$) on pre-$C_xH_y$- and C-covered Cu(111) single crystal substrates has been studied using temperature-programmed desorption (TPD) mass spectrometry. Chemisorbed PA with an acetylene group has been proved to be associated with hydrogen of pre-adsorbed $C_xH_y$ to form styrene (104 amu) on Cu surface. For the parent (PA) mass (102 amu) TPD profile, the TPD peaks at 360 K and 410 K are assigned to chemisorbed vertically aligned PA and flat-lying cross-bridged PA, respectively (J. Phys. Chem. C 2007, 111, 5101). The relative $I_{360K}/I_{410K}$ TPD ratio dramatically increases with increasing pre-adsorbed $C_xH_y$ before dosing PA, while the ratio does not increase for pre-C-covered surface. For PA on pre-$C_xH_y$-covered Cu(111) surface, styrene desorption is enhanced relative to the parent PA desorption, while styrene formation is dramatically quenched on pre-C-covered (lack of adsorbed hydrogen nearby) surface. It appears that only cross-bridged PA associates with adsorbed hydrogen to form styrene that promptly desorbs at 410 K, while vertically aligned PA is less likely to participate in forming styrene.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.249-249
• /
• 2012

The interaction of hydrogen with ZnO single crystal surfaces, ZnO(0001) and ZnO(000-1), has been investigated using a temperature programmed desorption (TPD) technique. Both surfaces do not interact with molecular hydrogen. When the ZnO(0001) is exposed to atomic hydrogen at 370 K, hydrogen is adsorbed in the surface and desorption takes place at around 460 K and 700 K. In ZnO(000-1), the desorption peaks are observed at around 440 K and 540 K. In both surfaces, as the atomic hydrogen exposure is further increased, the intensity of the low-temperature peak reaches maximum but the intensity of the high-temperature peak keeps increasing. In ZnO(000-1), the existence of hydrogen bonding to the surface O atoms and the bulk hydrogen has been confirmed by using X-ray photoelectron spectroscopy (XPS). When the Zn(0001) surface is exposed to atomic hydrogen at around 200 K, a new $H_2$ desorption peak has been observed at around 250 K. The intensity of the desorption feature at 250 K is much greater than that of the desorption feature at 460 K. This low-temperature desorption feature indicates hydrogen is bonded to surface Zn atoms. We will report the effect of the ZnO structure on the adsorption and bulk diffusion of hydrogen.

• Bulletin of the Korean Chemical Society
• /
• 제10권5호
• /
• pp.467-468
• /
• 1989

• 한국진공학회지
• /
• 제15권1호
• /
• pp.73-80
• /
• 2006

Si(100)에 주입된 불활성 기체 이온들의 열적 방출 특성을 열탈착(temperature-programmed desorption; TPD) 질량분석법으로 고찰하였다. 약 400K의 표면 온도 조건에서 1keV 비온빔에 시료를 노출시켜 주었을 때, He은 $500\~1100 K$의 넓은 온도 범위에서 Si(100)결정 밖으로 분출되어 나온 반면, Ne, Ar, 및 Kr은 각각 810, 860, 875 K 근처에서 매우 좁은 온도 범위에서 TPD 피크를 나타내며 급격하게 방출되었다. He+ 이온으로 처리된 Si(100)은 표면 원자 구조의 손상이 상대적으로 최소한으로 일어났지만, $Ne^+,\;Ar^+,\;Kr^+$ 등의 이온들로 처리된 경우는 질량이 클수록 표면이 원자 스케일로 더 심하게 손상되었음이 수소 흡탈착 분석 결과로 밝혀졌다. 이온빔에 의한 결정 내부의 결함 생성과 관련하여 이러한 실험적 결과가 시사하는 점들을 논의하였다

• 공업화학
• /
• 제20권6호
• /
• pp.658-662
• /
• 2009

본 연구에서는 탄소나노튜브를 KOH를 이용하여 활성화 한 후 이를 아민으로 표면처리한 탄소나노튜브의 이산화탄소 흡착거동에 관하여 고찰하였다. 아민 처리한 탄소나노튜브의 물리화학적 특성은 X-ray photoelectron spectroscopy (XPS), $N_2$ adsorption isotherm, thermogravimetric analysis (TGA), 그리고 temperature programmed desorption (TPD)을 이용하여 분석하였다. 실험 결과, 활성화된 탄소나노튜브 표면의 아미노 관능기는 산성가스인 이산화탄소를 선택적으로 흡착하기 위한 염기성 자리로서 작용하였다. 상온에서의 이산화탄소 흡착량은 미처리된 탄소나노튜브가 가장 크게 나타났으나 온도가 증가할수록 급격한 감소를 나타내었으며 PEHA 처리한 경우 완만한 흡착거동을 보였다. 이는 탄소표면의 아미노 관능기와 이산화탄소 사이의 상호작용 때문이라 판단된다.