Insight into the catalytic performance and reaction routes for toluene total oxidation over facilely prepared Mn-Cu bimetallic oxide catalysts

• Published in: Applied surface science 2021-06, Vol.550, p.149179, Article 149179
• Main Authors: Li, Jian-Rong, Zhang, Wan-Peng, Li, Chang, Xiao, Hang, He, Chi
• Format: Article
• Language: English
• Subjects: Catalytic oxidation; Hydrothermal-redox; Mn-Cu bimetallic oxides; PTR-MS; Toluene
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.149179

[Display omitted] •Mn-Cu bimetallic catalysts were facilely prepared by one-step hydrothermal-redox method.•Hydrothermal-redox was superior to other preparation methods for Mn-Cu catalysts.•MnCu spinel type catalyst exhibited excellent low-temperature catalytic performance.•PTR-MS results revealed the reaction routes of toluene oxidation over MnCu catalyst. Developing facile preparation method to obtain the satisfied low-temperature catalytic performance of transitional metal oxide-based materials is still a challenge in deep degradation of VOCs. Here, a series of Mn-Cu bimetallic oxide catalysts were prepared by one-step hydrothermal-redox method for catalytic total oxidation of toluene. The CH3COOH concentration, Cu/Mn molar ratio and calcination temperature greatly affected the crystal structure, micromorphology and catalytic performance. Amongst, MnCu spinel structured catalyst exhibited excellent low-temperature catalytic activity, superior durability and water resistance in toluene total oxidation owing to its abundant surface adsorbed oxygen species, higher amount of Cu+ and Mn3+ and excellent low-temperature reducibility. The reaction rate of MnCu was 7.0 times higher than that of MnCu0.5 at 210 °C. The cyclic redox process with enough oxygen vacancy played a vital role in toluene oxidation. The deep oxidation of benzene was the key step in the toluene oxidation. Proton transfer reaction-mass spectrometry (PTR-MS) results revealed the reaction intermediates including benzaldehyde, benzene and phenol, which further decomposed to acetone, ethanol, acetic acid, ketone and acetaldehyde by ring opening before total mineralization. Therefore, PTR-MS provided a facile method to investigate the reaction mechanism of toluene oxidation.