High-performance benzyl alcohol oxidation catalyst: Au-Pd alloy with ZrO2 as promoter

• Published in: Applied surface science 2021-01, Vol.537, p.148059, Article 148059
• Main Authors: Wu, Pingping, Song, Lei, Wang, Yue, Liu, Xuehua, He, Zhengke, Bai, Peng, Yan, Zifeng
• Format: Article
• Language: English
• Subjects: Benzyl alcohol partial oxidation; Lewis acid sites; Oxygen transfer; Selectivity
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2020.148059

Enhanced catalytic performance was obtained on ZrO2 promoted Au-Pd catalysts for benzyl alcohol oxidation. The introduction of ZrO2 produced more active sites for O2 activation and more surface Lewis acid sites for preventing benzaldehyde from over-oxidation. [Display omitted] •The introduction of ZrO2 (5 wt%) produced more surface Lewis acid sites.•Lewis acid sites interacted with benzaldehyde, inhibiting over-oxidation and achieving high benzaldehyde selectivity.•The addition of small amount of ZrO2 led to the formation of more active sites for O2 activation.•ZrO2 serves as an oxygen transfer medium to improve the O transfer during the reaction. Achieving the balance between the catalytic activity and product selectivity still remains a challenge in partial oxidation processes, because the products are prone to be over-oxidized. Lewis acids (such as AlCl3) have previously been identified to interact with CO groups, which can prevent the ketone products from further transformation. In this work, ZrO2 promoted Au-Pd/γ-Al2O3 catalyst was designed to enhance the benzaldehyde selectivity by generating more surface Lewis acid site on ZrO2-modified alumina. Results show that the introduction of ZrO2 (5%) resulted in the formation of more surface Lewis acid sites, which improved the benzaldehyde selectivity through the strengthened interaction between the Lewis acid sites and CO groups in benzaldehyde. Besides, the addition of small amount of ZrO2 enhanced the noble metal dispersion and led to the formation of more active sites to improve the oxygen transfer during the reaction.