Catalytic Performance and Reaction Mechanisms of Ethyl Acetate Oxidation over the Au–Pd/TiO[sub.2] Catalysts

• Published in: Catalysts Vol. 13; no. 4
• Main Authors: Bao, Minming, Liu, Yuxi, Deng, Jiguang, Jing, Lin, Hou, Zhiquan, Wang, Zhiwei, Wei, Lu, Yu, Xiaohui, Dai, Hongxing
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.03.2023
• Subjects: Acetates; Air quality management; Benzene; Catalysts; Esters; Oxidation-reduction reaction; China
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal13040643

The development of efficient and stable catalysts is of great importance for the elimination of volatile organic pollutants (VOCs). In this work, AuPdx nanoparticles (NPs) were loaded on TiO[sub.2] through the electrostatic adsorption approach to generate the yAuPdx/TiO[sub.2] (i.e., 0.35AuPd[sub.0.46]/TiO[sub.2], 0.34AuPd[sub.2.09]/TiO[sub.2], and 0.37AuPd[sub.2.72]/TiO[sub.2]; x and y are Pd/Au molar ratio and AuPdx loading, respectively; x = 0.46-2.72; and y = 0.34-0.37 wt%) catalysts, and their catalytic activities for the oxidation of ethyl acetate were determined. The results showed that the 0.37AuPd[sub.2.72]/TiO[sub.2] sample exhibited the best activity (T[sub.50%] = 217 °C and T[sub.90%] = 239 °C at SV = 40,000 mL/(g h), E[sub.a] = 37 kJ/mol, specific reaction rate at 220 °C = 113.8 µmol/(g[sub.Pd] s), and turnover frequency (TOF[sub.Noble metal]) at 220 °C = 109.7 × 10[sup.−3] s[sup.−1]). The high catalytic performance of the 0.37AuPd[sub.2.72]/TiO[sub.2] sample was attributed to the good dispersion of AuPd[sub.2.72] NPs, the strong redox ability, the large ethyl acetate adsorption capacity, and the strong interaction between AuPdx and TiO[sub.2]. Acetaldehyde, ethanol, and acetic acid are the main intermediates in the oxidation of ethyl acetate, and the loading of AuPdx NPs effectively reduces the formation of the toxic by-product acetaldehyde. The oxidation of ethyl acetate over the 0.34AuPd[sub.2.09]/TiO[sub.2] sample might occur via the pathway of ethyl acetate → ethanol → acetic acid → acetate → CO[sub.2] and H[sub.2]O. We believe that the obtained results may provide a useful idea for the design of bimetallic catalysts under industrial conditions and for understanding the VOCs oxidation mechanisms.