Accelerated Catalytic Ozonation in a Mesoporous Carbon-Supported Atomic Fe-N4 Sites Nanoreactor: Confinement Effect and Resistance to Poisoning

The nanoconfinement effect significantlyaccelerates thecatalytic ozonation for sulfur-containing VOC elimination in Fe-N-4/CMK-3 nanoreactors due to the unique nanochannel microenvironmentin electronic and geometric aspects. The design of a micro-/nanoreactor is of great significanceforcatalytic ozonation, which can achieve effective mass transfer andexpose powerful reaction species. Herein, the mesoporous carbon withatomic Fe-N-4 sites embedded in the ordered carbonnanochannels (Fe-N-4/CMK-3) was synthesized by thehard-template method. Fe-N-4/CMK-3 can be employedas nanoreactors with preferred electronic and geometric catalyticmicroenvironments for the internal catalytic ozonation of CH3SH. During the CH3SH oxidation process, the mass transfercoefficient of the Fe-N-4/CMK-3 confined system withsufficient O-3 transfer featured a level of at least 1.87x 10(-5), which is 34.6 times that of the Fe-N-4/C-Si unconfined system. Detailed experimental studiesand theoretical calculations demonstrated that the anchored atomicFe-N-4 sites and nanoconfinement effects regulatedthe local electronic structure of the catalyst and promoted the activationof O-3 molecules to produce atomic oxygen species (AOS)and reactive oxygen species (ROS), eventually achieving efficientoxidation of CH3SH into CO2/SO4 (2-). Benefiting from the high diffusion rate and theaugmentation of AOS/ROS, Fe-N-4/CMK-3 exhibited anexcellent poisoning tolerance, along with high catalytic durability.This contribution provides the proof-of-concept strategy for acceleratingcatalytic ozonation of sulfur-containing volatile organic compounds(VOCs) by combining confined catalysis and atomic catalysts and canbe extended to the purification of other gaseous pollutants.

Automated summary

The nanoconfinement effect in Fe-N-4/CMK-3 nanoreactors greatly accelerates the catalytic ozonation for sulfur-containing VOC elimination due to the unique nanochannel microenvironment. The design of a micro-/nanoreactor is essential for catalytic ozonation to achieve effective mass transfer and expose powerful reaction species.