In this study, the catalytic activity of γ-Al2O3 was investigated for the decomposition of NF3. Reactions for NF3 decomposition were carried out in the range of reaction temperature of 330∼730 ℃ and GHSV of 3,000∼15,000 mL/g-cat?h in a fixed-bed catalytic reactor system. Thermal decomposition of NF3 was also performed in order to compare with the catalytic decomposition of NF3. The conversion of NF3 by the catalytic decomposition at 400 ℃ was four times higher than that of the thermal decomposition. It was confirmed that the reaction behavior of NF3 over γ-Al2O3 exhibited two reaction pathways in the presence of steam. Fluorine in NF3 over γ-Al2O3 was chemically absorbed to AlF3 by the gas-solid reaction in the absence of steam. The catalytic decomposition of NF3 occurred by hydrolysis with steam. It was also confirmed by FT-IR analysis that NF3 was completely decomposed to NOx and HF above 500 ℃.

본 연구에서는 NF3의 분해를 위한 γ-Al2O3의 촉매활성을 조사하였다. NF3 분해반응은 고정층 촉매반응기에서 330∼730 ℃ 범위의 반응온도와 3,000∼15,000 mL/g-cat·h의 공간속도 조건에서 수행되었고, NF3의 열분해 반응이 촉매분해반응와 비교를 위하여 함께 수행되었다. 400 ℃의 촉매분해 반응에서 NF3의 전화율은 열분해 반응보다 4배 정도 높았으며, γ-Al2O3상에서 NF3의 반응거동은 스팀의 존재에 따라 두 가지 반응경로를 나타내는 것으로 확인되었다. 스팀이 존재하지 않은 조건에서는 기체-고체 반응에 의해서 NF3에 함유된 불소성분은 AlF3로 전이되고, 스팀이 존재하는 조건에서는 가수분해에 의한 촉매적 분해반응이 일어난다. 또한 NF3는 500 ℃ 이상에서 NOx와 HF로 완전히 분해되는 것으로 FT-IR분석에서 확인되었다.