Methanol Oxidation Catalytic Performance Enhancement via Constructing Pd-MgAl2O4 Interface and its Reaction Mechanism Investigation

• Published in: Catalysis letters 2023-06, Vol.153 (6), p.1786-1796
• Main Authors: Zhao, Wei, Zhang, Hongyi, Zhang, Lei, Gong, Jianchao, Chen, Tianen, Ren, Liming, Ji, Yaxiong, Meng, Fanbin
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysis; Catalysts; Chemisorption; Chemistry; Chemistry and Materials Science; Diffuse reflectance spectroscopy; Exhaust gases; Fourier transforms; High resolution electron microscopy; Industrial Chemistry/Chemical Engineering; Methanol; Organometallic Chemistry; Oxidation; Oxygen; Palladium; Physical Chemistry; Reaction mechanisms; Strong interactions (field theory); Surface reactions
• ISSN: 1011-372X; 1572-879X
• DOI: 10.1007/s10562-022-04107-y

The methanol oxidation reaction is a promising route to eliminating trace amount of methanol in exhaust gases which aroused serious environmental concern. In this work, a novel Pd/MgAl 2 O 4 catalyst was prepared to construct the metal-support interface and employed in the methanol oxidation reaction. The reaction results show that the Pd/MgAl 2 O 4 catalyst could achieve 100% methanol oxidation at 198 ℃ over the Pd/MgO and Pd/Al 2 O 3 catalysts. The high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), CO-chemisorption, H 2 temperature programmed reduction (H 2 -TPR), and CO diffuse reflectance infrared Fourier transformed spectroscopy (CO-DRIFTS) show that the Pd was uniformly distributed over the MgAl 2 O 4 support due to strong interaction between Pd and MgAl 2 O 4 . The mechanism studies show that the abundant Pd-MgAl 2 O 4 interfaces significantly contributed to the reaction enhancement. The Pd-MgAl 2 O 4 interfaces could greatly enhance the oxidation reaction at a lower temperature with the assistance of oxygen vacancies compared with traditional oxide catalysts, which was confirmed by methanol temperature program surface reaction (MeOH-TPSR) experiments. In-situ DRIFTS is carried out to elucidate the reaction mechanism and establish the structure − activity relationship: the methanol could be effectively absorbed on the MgAl 2 O 4 support with oxygen vacancies to form bidentate formate, then the Pd species assisted the intermediates converting to CO 2 product. The Pd/MgAl 2 O 4 catalyst and its enhancement mechanism investigation provided a potential strategy in the VOCs removal catalysis development. Graphical Abstract