Enhanced Performance and Conversion Pathway for Catalytic Ozonation of Methyl Mercaptan on Single-Atom Ag Deposited Three-Dimensional Ordered Mesoporous MnO.

In this study, Ag deposited three-dimensional MnO porous hollow microspheres (Ag/MnO PHMSs) with high dispersion of the atom level Ag species are first prepared by a novel method of redox precipitation. Due to the highly efficient utilization of downsized Ag nanoparticles, the optimal 0.3% Ag/MnO PHMSs can completely degrade 70 ppm CHSH within 600 s, much higher than that of MnO PHMSs (79%). Additionally, the catalyst retains long-term stability and can be regenerated to its initial activity through regeneration with ethanol and HCl. The results of characterization of Ag/MnO PHMSs and catalytic performance tests clearly demonstrate that the proper amount of Ag incorporation not only facilitates the chemi-adsorption but also induces more formation of vacancy oxygen (O) and lattice oxygen (O) in MnO as well as Ag species as activation sites to collectively favor the catalytic ozonation of CHSH. Ag/MnO PHMSs can efficiently transform CHSH into CHSAg/CHS-SCH and then oxidize them into SO and CO as evidenced by in situ diffuse reflectance infrared Fourier transform spectroscopy. Meanwhile, electron paramagnetic resonance and scavenger tests indicate that •OH and O are the primary reactive species rather than surface atomic oxygen species contributing to CHSH removal over Ag/MnO PHMSs. This work presents an efficient catalyst of single atom Ag incorporated MnO PHMSs to control air pollution.