• 공업화학
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• 제34권6호
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• pp.674-678
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• 2023

고정층 상압 유통식 반응기를 사용하여 Pt(1)-Fe(30)/MCM-41와 Fe(30)/MCM-41의 촉매상에서 메탄의 분해 반응을 수행하여 수소의 수율을 구하여 Pt의 효과를 조사하였다. XRD 분석으로 반응 전 Pt(1)-Fe(30)/MCM-41 촉매에서 Fe₂O₃와 Pt의 결정상이 나타났다. SEM, EDS 분석과 매핑 이미지로부터 촉매 표면상에 Fe, Pt, Si, O의 나노 입자들이 균일하게 분포함을 알 수 있었다. XPS 분석으로 Pt⁰, Pt²⁺, Pt⁴⁺, Ft⁰, Fe²⁺, Fe³⁺ 등의 이온과 O^2-, O^-의 산소종이 존재함을 알 수 있었고, Fe(30)/MCM-41 촉매에 Pt를 1 wt% 첨가하면 촉매 표면상에서 Fe2p의 원자 백분율이 13.39%에서 16.14%로 증가하고 Pt4f는 1.51%이었다. 수소의 수율은 Fe(30)/MCM-41보다 3.2배 높았다. Pt로부터 Fe로 H₂의 스필오버(spillover) 효과로 Fe 입자의 환원을 증가시키고, Fe, Pt와 MCM-41의 적당한 상호작용으로 미세한 나노입자를 촉매 표면상에 균일하게 분산을 증가시켜 수소수율을 향상시켰다.

• 한국표면공학회지
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• 제38권2호
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• pp.65-68
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• 2005

The effect of crystal orientation and microstructure on the mechanical properties of $TaN_x$ was investigated. $TaN_x$ films were grown on $SiO_2$ substrates by ultrahigh vacuum unbalanced magnetron sputter deposition in mixed $Ar/N_2$ discharges at 20 mTorr (2.67 Pa) and at $350^{\circ}C$. Unlike the Ti-N system, in which TiN is the terminal phase, a large number of N-rich phases in the Ta-N system could lead to layers which had nano-sized lamella structure of coherent cubic and hexagonal phases, with a correct choice of nitrogen fraction in the sputtering mixture and ion irradiation energy during growth. The preferred orientations and the micro-structure of $TaN_x$ layers were controlled by varing incident ion energy $E_i\;(=30eV\~50eV)$ and nitrogen fractions $f_{N2}\;(=0.1\~0.15)$. $TaN_x$ layers were grown on (0002)-Ti underlayer as a crystallographic template in order to relieve the stress on the films. The structure of the $TaN_x$ film transformed from Bl-NaCl $\delta-TaN_x$ to lamellar structured Bl-NaCl $\delta-TaN_x$ + hexagonal $\varepsilon-TaN_x$ or Bl-NaCl $\delta-TaN_x$ + hexagonal $\gamma-TaN_x$ with increasing the ion energy at the same nitrogen fraction $f_{N2}$. The hardness of the films also increased by the structural change. At the nitrogen fraction of $0.1\~0.125$, the structure of the $TaN_x$ films was changed from $\delta-TaN_x\;+\;\varepsilon-TaN_x\;to\;\delta-TaN_x\;+\;\gamma-TaN_x$ with increasing the ion energy. However, at the nitrogen fraction of 0.15 the film structure did not change from $\delta-TaN_x\;+\;\varepsilon-TaN_x$ over the whole range of the applied ion energy. The hardness increased significantly from 21.1 GPa to 45.5 GPa with increasing the ion energy.