Accelerated Catalytic Ozonation in a Mesoporous Carbon-Supported Atomic Fe–N<sub>4</sub> Sites Nanoreactor: Confinement Effect and Resistance to Poisoning
Wei Qu, Manhui Luo, Zhuoyun Tang, Tao P. Zhong, Huinan Zhao, Lingling Hu, Dehua Xia, Shuanghong Tian, Dong Shu, Chun He
Abstract
The design of a micro-/nanoreactor is of great significance for catalytic ozonation, which can achieve effective mass transfer and expose powerful reaction species. Herein, the mesoporous carbon with atomic Fe–N 4 sites embedded in the ordered carbon nanochannels (Fe–N 4 /CMK-3) was synthesized by the hard-template method. Fe–N 4 /CMK-3 can be employed as nanoreactors with preferred electronic and geometric catalytic microenvironments for the internal catalytic ozonation of CH 3 SH. During the CH 3 SH oxidation process, the mass transfer coefficient of the Fe–N 4 /CMK-3 confined system with sufficient O 3 transfer featured a level of at least 1.87 × 10 –5, which is 34.6 times that of the Fe–N 4 /C–Si unconfined system. Detailed experimental studies and theoretical calculations demonstrated that the anchored atomic Fe–N 4 sites and nanoconfinement effects regulated the local electronic structure of the catalyst and promoted the activation of O 3 molecules to produce atomic oxygen species (AOS) and reactive oxygen species (ROS), eventually achieving efficient oxidation of CH 3 SH into CO 2 /SO 4 2– . Benefiting from the high diffusion rate and the augmentation of AOS/ROS, Fe–N 4 /CMK-3 exhibited an excellent poisoning tolerance, along with high catalytic durability. This contribution provides the proof-of-concept strategy for accelerating catalytic ozonation of sulfur-containing volatile organic compounds (VOCs) by combining confined catalysis and atomic catalysts and can be extended to the purification of other gaseous pollutants.