Catalytic decomposition of NF3 by thermal decomposition and hydrolysis of γ-Al2O3

Abstract

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 °C 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 °C 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 °C.