A core-shell structured crystalline@amorphous MnO2 with enhanced plasma catalytic degradation performance for Volatile Organic Sulfur Compounds and degradation mechanism exploration

Abstract

A crystalline@amorphous MnO₂ (HT@RT) plasma catalyst was successfully constructed in this study to address the problem of odor pollution, especially from volatile organic sulfur compounds (VOSCs) with low olfactory thresholds. Complete conversion of dimethyl sulfide (DMS) at 140 J/L was achieved, and the ozone concentration in the exhaust gas was maintained below 5 ppm. Deeper mineralization of DMS was achieved in the HT@RT sample than in the individual HT and RT samples. A comprehensive analysis of multiple characterization techniques revealed that the HT@RT sample exhibited excellent DMS adsorption capacity, appropriate electric field responsiveness, high oxygen vacancy content, and abundant reactive oxygen species, which play key roles in the degradation of DMS. In addition, the DMS degradation process was investigated using in situ plasma diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Combined with the results of gas chromatography-mass spectrometry, degradation pathways for DMS were proposed. The HT@RT sample combined the advantages of both amorphous and crystalline materials, significantly enhancing the activity and stability of the catalyst. Therefore, the crystalline@amorphous structured catalysts constructed in this study not only offer new insights for improving the performance of plasma catalysis but also provide an effective solution for eliminating odorous gases.