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.

In this study, Ag deposited three-dimensional MnO 2 porous hollow microspheres (Ag/MnO 2 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 2 PHMSs can completely degrade 70 ppm CH 3 SH within 600 s, much higher than that of MnO 2 PHMSs (79%). Additionally, the catalyst retains longterm stability and can be regenerated to its initial activity through regeneration with ethanol and HCl. The results of characterization of Ag/MnO 2 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 v ) and lattice oxygen (O L ) in MnO 2 as well as Ag species as activation sites to collectively favor the catalytic ozonation of CH 3 SH. Ag/MnO 2 PHMSs can efficiently transform CH 3 SH into CH 3 SAg/CH 3 S-SCH 3 and then oxidize them into SO 4 2− and CO 2 as evidenced by in situ diffuse reflectance infrared Fourier transform spectroscopy. Meanwhile, electron paramagnetic resonance and scavenger tests indicate that •OH and 1 O 2 are the primary reactive species rather than surface atomic oxygen species contributing to CH 3 SH removal over Ag/MnO 2 PHMSs. This work presents an efficient catalyst of single atom Ag incorporated MnO 2 PHMSs to control air pollution.

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A self-stabilized Z-scheme porous g-CN/I-containing BiOI ultrathin nanosheets (g-CN/I-BiOI) heterojunction photocatalyst with I/I redox mediator was successfully synthesized by a facile solvothermal method coupling with light illumination. The structure and optical properties of g-CN/I-BiOI composites were systematically characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, N adsorption/desorption, UV-vis diffuse reflectance spectrum, and photoluminescence. The g-CN/I-BiOI composites, with a heterojunction between porous g-CN and BiOI ultrathin nanosheets, were first applied for the photocatalytic elimination of ppm-leveled CHSH under light-emitting diode visible light illumination. The g-CN/I-BiOI heterojunction with 10% g-CN showed a dramatically enhanced photocatalytic activity in the removal of CHSH compared with pure BiOI and g-CN due to its effective interfacial charge transfer and separation. The adsorption and photocatalytic oxidation of CHSH over g-CN/I-BiOI were deeply explored by in situ diffuse reflectance infrared Fourier transform spectroscopy, and the intermediates and conversion pathways were elucidated and compared. Furthermore, on the basis of reactive species trapping, electron spin resonance and Mott-Schottky experiments, it was revealed that the responsible reactive species for catalytic CHSH composition were h, O, and O; thus, the g-CN/I-BiOI heterojunction followed an indirect all-solid state Z-scheme charge-transfer mode with self-stabilized I/I pairs as redox mediator, which could accelerate the separation of photogenerated charge and enhance the redox reaction power of charged carriers simultaneously.

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Catalytic ozonation of methyl mercaptan (CH3SH) can effectively control this unbearable odorous sulfur-containing volatile organic compound (S-VOC). The construction of an electronic metal–support interaction (EMSI) coordination structure to maximize the number of active sites and increase the intrinsic activity of active sites is an effective means to improve catalytic performance. In this work, the abundant Si–OH groups on PSBA-15 (SBA-15 before calcination) were used to anchor Mn to form a Si–O–Mn-based EMSI coordination structure. Detailed characterizations and theoretical simulations reveal that the strong EMSI effect significantly adjusts and stabilizes the electronic structure of Mn 3d states, resulting in an electron-rich center on the Si–O–Mn bond to promote the specific adsorption/activation of ozone (O3) and an electron-poor center on the (Si–O−)­Mn–O bond to adsorb a large amount of CH3SH accompanied by its own oxidative degradation. In situ Raman and in situ Fourier transform infrared (FTIR) analyses identify that catalytic ozonation over 3.0Mn-PSBA generates atomic oxygen species (AOS/*O) and reactive oxygen species (ROS/•O2 –) to achieve efficient decomposition of CH3SH into CO2/SO4 2–. Furthermore, the electrons obtained from CH3SH in electron-poor centers are transferred to maintain the redox cycle of Mn2+/3+ → Mn4+ → Mn2+/3+ through the internal bond bridge, thus accomplishing the efficient and stable degradation of CH3SH prolonged to 180 min. Therefore, the rational design of catalysts with abundant active sites and optimized inherent activity via the EMSI effect can provide significant potential to improve catalytic performance and eliminate odorous gases.

Constructing catalysts with electronic metal–support interaction (EMSI) is promising for catalytic reactions. Herein, graphene-supported positively charged (Pt2+/Pt4+) atomically dispersed Pt catalysts (AD-Pt-G) with Pt x C3 (x = 1, 2, and 4)-based EMSI coordination structures are achieved for boosting the catalytic ozonation for odorous CH3SH removal. A CH3SH removal efficiency of 91.5% can be obtained during catalytic ozonation using optimum 0.5AD-Pt-G within 12 h under a gas hourly space velocity of 60,000 mL h–1 g–1, whereas that of pure graphene is 40.4%. Proton transfer reaction time-of-flight mass spectrometry, in situ diffuse reflectance infrared Fourier transform spectroscopy/Raman, and electron spin resonance verify that the Pt x C3 coordination structure with atomic Pt2+ sites on AD-Pt-G can activate O2 to generate peroxide species (*O2) for partial oxidation of CH3SH during the adsorption period and trigger O3 into surface atomic oxygen (*Oad), *O2, and superoxide radicals (·O2 –) to accomplish a stable, high-efficiency, and deeper oxidation of CH3SH during the catalytic ozonation stage. Moreover, the results of XPS and DFT calculation imply the occurrence of Pt2+ → Pt4+ → Pt2+ recirculation on Pt x C3 for AD-Pt-G to maintain the continuous catalytic ozonation for 12 h, i.e., Pt2+ species devote electrons in 5d-orbitals to activate O3, while Pt4+ species can be reduced back to Pt2+ via capturing electrons from CH3SH. This study can provide novel insights into the development of atomically dispersed Pt catalysts with a strong EMSI effect to realize excellent catalytic ozonation for air purification.