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The oxygen vacancy in MnO2 is normally proved as the reactive site for the catalytic ozonation, and acquiring a highly reactive crystal facet with abundant oxygen vacancy by facet engineering is advisable for boosting the catalytic activity. In this study, three facet-engineered α-MnO2 was prepared and successfully utilized for catalytic ozonation toward an odorous CH3SH. The as-synthesized 310-MnO2 exhibited superior activity in catalytic ozonation of CH3SH than that of 110-MnO2 and 100-MnO2, which could achieve 100% removal efficiency for 70 ppm of CH3SH within 20 min. The results of XPS, Raman, H2-TPR, and DFT calculation all prove that the (310) facets possess a higher surface energy than other facets can feature the construction of oxygen vacancies, thus facilitating the adsorption and activate O3 into intermediate peroxide species (O2–/O2 2–) and reactive oxygen species (•O2 –/1O2) for eliminating adjacent CH3SH. In situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) revealed that the CH3SH molecular was chemisorbed on S atom to form CH3S–, which was further converted into intermediate CH3SO3 – and finally oxidized into SO4 2– and CO3 2–/CO2 during the process. Attributed to the deep oxidation of CH3SH on 310-MnO2 via efficient cycling of active oxygen vacancies, the lifetime of 310-MnO2 can be extended to 2.5 h with limited loss of activity, while 110-MnO2 and 100-MnO2 were inactivated within 1 h. This study deepens the comprehension of facet-engineering in MnO2 and presents an efficient and portable catalyst to control odorous pollution.

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Water-soluble organic compounds (WSOC) and methanol-soluble organic compounds (MSOC) in smoke particles emitted from residential coal combustion were characterized by ultrahigh-resolution mass spectrometry. The results showed that the molecular compositions of WSOC and MSOC are different. S-containing compounds (CHOS and CHONS) are found to be the dominant components (65–87%) of the WSOC, whereas CHO and CHON compounds make a great contribution (79–96%) to the MSOC samples. It is worth noting that greater abundance of S-containing compounds was found in smoke produced from coal combustion compared to biomass burning and atmospheric samples. The molecular compositions of WSOC and MSOC also varied significantly depending on the maturity of the coal. The WSOC and MSOC derived from the combustion of low-maturity coal contained a higher proportion of oxidized functional groups but with a lower degree of aromaticity than the compounds derived from the combustion of high-maturity coal. Our findings suggest that organic molecules with a high modified aromaticity index, low O/C ratio, and low polarity showed stronger light absorption. This study also suggests that CHO and CHON compounds significantly contributed to the light absorption of WSOC and MSOC and that the contribution of CHON may be stronger.