Role of acidity in catalytic cracking of n-decane over supported Pt-based catalysts

• Published in: Applied surface science 2020-03, Vol.507, p.145113, Article 145113
• Main Authors: Zhang, Jun, Chen, Ting, Jiao, Yi, Wang, Linlin, Wang, Jianli, Chen, Yaoqiang, Zhu, Quan, Li, Xiangyuan
• Format: Article
• Language: English
• Subjects: Acidity; Catalytic cracking; Coking behavior; n-Decane; Oxide catalyst
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.145113

[Display omitted] •Acidity of catalyst can be adjusted by combination of different acidic-basic oxide.•Catalytic activity is closely related to amount and distribution of acid sites.•30 wt% SiO2-modified Al2O3 owns proper amount and distribution of acid sites.•Pt/SiO2-Al2O3 catalyst exhibited the highest heat sink of 3.920 MJ/kg.•Coverage of active sites is one of the main factors to catalyst deactivation. Different acidic-basic oxides, Al2O3, SiO2, MgO, MgO-SiO2, MgO-Al2O3 and SiO2-Al2O3, were employed as supports of Pt-based catalysts for n-decane cracking, aiming to investigate the effect of acidity on cracking activity and coking behaviors. The as-prepared catalysts were characterized by the techniques of N2 absorption-desorption, X-ray diffraction (XRD), CO chemisorption, temperature programmed desorption of ammonia (NH3-TPD) and Fourier transform infrared spectroscopy (FTIR) of adsorbed pyridine. The results showed that acidic support catalysts are more suitable for catalytic cracking reaction of n-decane than alkaline support catalyst. Particularly, Pt/SiO2-Al2O3 catalyst exhibited the optimal catalytic activity, leading to heat sink of 3.920 MJ/kg and n-decane conversion of 85.5% at 750 °C. Meanwhile, excellent cracking activity over Pt/SiO2-Al2O3 catalyst is due to large ratio of strong to total acid sites and large amount of Lewis acid sites. Additionally, stability and regeneration experiments of Pt/SiO2-Al2O3 showed that coverage of active sites due to coke deposition is main factor to catalyst deactivation, and carburization of Pt metals will lead to the reduction of catalytic activity.