biostudies-literatureKong COpen Foundation of Engineering Research Center of Construction Technology of Precast Concrete of Zhejiang ProvinceNational Natural Science Foundation of ChinaJiangsu Provincial Department of Education8640-8650https://www.ebi.ac.uk/biostudies/studies/S-EPMC8928516biostudies-literatureUnknown7(10)Plasma-assisted catalysis has been demonstrated to be an innovative technology for eliminating diesel particulate matter (DPM) efficiently at low temperature (≤200 °C). Moreover, past studies have demonstrated that CaSO₄, which exists in small concentrations (<2%) in DPM and is toxic in thermal catalytic oxidation processes, actually enhances DPM oxidation during plasma-assisted catalytic processes. However, the role CaSO₄ plays in this promotion of DPM oxidation still remains unclear. The present study addresses this issue by investigating the underlying mechanisms of DPM oxidation during plasma-assisted catalytic processes using graphitic carbon as a surrogate DPM material in conjunction with CaSO₄- and Au-impregnated γ-Al₂O₃ catalysts. The results of mass spectrometry and in situ diffuse reflectance infrared Fourier transform spectroscopy, which employs an in situ cell with a small dielectric barrier discharge space over the catalyst bed, demonstrate that CaSO₄ can save and release O atoms contributing to graphite oxidation via the -S=O units of CaSO₄ through a reversible surface reaction (-S=O + O → -S(-O)₂). The results are employed to propose a formal mechanism of graphite oxidation catalyzed by CaSO₄ and Au. These findings both improve our understanding of the plasma-assisted catalytic oxidation mechanisms of DPM and support the development of efficient plasma-assisted catalysts.ACS omegaPromotion Mechanism of CaSO₄ and Au in the Plasma-Assisted Catalytic Oxidation of Diesel Particulate Matter.PMC8928516ZZP1902SJCX20_093412075037Li GWu ZLi JZhu JYao SKong CfalsePromotion Mechanism of CaSO₄ and Au in the Plasma-Assisted Catalytic Oxidation of Diesel Particulate Matter.Plasma-assisted catalysis has been demonstrated to be an innovative technology for eliminating diesel particulate matter (DPM) efficiently at low temperature (≤200 °C). Moreover, past studies have demonstrated that CaSO₄, which exists in small concentrations (<2%) in DPM and is toxic in thermal catalytic oxidation processes, actually enhances DPM oxidation during plasma-assisted catalytic processes. However, the role CaSO₄ plays in this promotion of DPM oxidation still remains unclear. The present study addresses this issue by investigating the underlying mechanisms of DPM oxidation during plasma-assisted catalytic processes using graphitic carbon as a surrogate DPM material in conjunction with CaSO₄- and Au-impregnated γ-Al₂O₃ catalysts. The results of mass spectrometry and in situ diffuse reflectance infrared Fourier transform spectroscopy, which employs an in situ cell with a small dielectric barrier discharge space over the catalyst bed, demonstrate that CaSO₄ can save and release O atoms contributing to graphite oxidation via the -S=O units of CaSO₄ through a reversible surface reaction (-S=O + O → -S(-O)₂). The results are employed to propose a formal mechanism of graphite oxidation catalyzed by CaSO₄ and Au. These findings both improve our understanding of the plasma-assisted catalytic oxidation mechanisms of DPM and support the development of efficient plasma-assisted catalysts.2022-01-01T00:00:00Z2022 Mar2025-04-18T20:23:31.96Z2025-04-07T08:21:46.667ZS-EPMC89285163530944510.1021/acsomega.1c06659