Highly active mesoporous Co–Al2O3 sorbents for the efficient destructive sorption of NF3

Nitrogen trifluoride (NF3) is widely used as an etching gas and cleaning agent in the microelectronics industry. However, it is a novel and powerful greenhouse gas. The destructive sorption of NF3 over metal oxides is an efficient route to control its emission. Here, several sorbents of homogeneous Co–Al2O3 oxides were prepared via changing the molar ratios of HNO3 to Al(OPri)3 in the raw materials, whose impact on the structure of sorbents and the reactivity for NF3 destructive sorption was investigated. It is found that the destructive reactivity of sorbents is strongly affected by their surface area and pore volume. Impressively, the optimal Co–Al2O3-2.45 sorbent with the largest surface area and pore volume presents the longest time of NF3 complete destruction, which is clearly more active than most of the results in the literature. Furthermore, the F migration over the solid interfaces between Al2O3 and Co oxides in Co–Al2O3 sorbents enhances the efficient destruction of NF3. These findings well explain the better reactivity of Co–Al2O3 complex oxides than bare Al2O3, and are beneficial to develop more efficient sorbents for NF3 destruction.