Disentangling activity-stability trade-off in the catalytic degradation of malodorous sulfur-containing VOCs driven by active sites' self-dynamic evolution.

The catalytic degradation of malodorous sulfur-containing volatile organic compounds (S-VOCs), especially methanethiol (CHSH), faces an enormous challenge in striking a balance between activity and stability. Herein, we develop the time-tandem and spatial-extended strategy for synthesizing t-MoO/meso-SiO nano-reactor-type catalysts and reveal the migration and transformation behaviors of both carbon and sulfur species at the mesoscopic scale to break the catalytic CHSH activity and stability trade-off. The dynamic evolution of active centers from initial oxygen sites and acid sites to sulfur vacancies in MoS during the reaction process as well as the formation of a new dimethyl disulfide (CHSSCH) reaction pathway are identified as the main reason for the catalysts' superior activity and sulfur resistance. H-TPR, XPS, Raman spectroscopy and other characterizations suggested that the final deactivation is transformed from the conventional sulfide and sulfate poisoning mechanism to MoS active phase destroying mechanism. Extending the micropore to mesopore also contributes to the high sulfur-resistance stability due to the greater ability to accommodate deposited elemental sulfur. Furthermore, t-MoO/meso-SiO catalysts have confirmed the excellent performance in the catalytic degradation of dual-component thiols and CHSH with water vapor present in the realistic environment, also substantiating its wide application potential in the catalytic degradation of S-VOCs.