Hydroisomerization of n-hexadecane over a Pd–Ni2P/SAPO-31 bifunctional catalyst: synergistic effects of bimetallic active sites. Issue 3 (12th January 2018)

• Record Type: Journal Article
• Authors: Zhang, Yang; Wang, Wei; Jiang, Xin; Su, Xiaofang; Kikhtyanin, O. V.; Wu, Wei
• Is Part Of: Catalysis science & technology. Volume 8:Issue 3(2018)
• Page Start: 817
• Page End: 828
• Publication Date: 2018-01-12
• Subjects: Catalysis -- Periodicals; 541.395
• DOI: 10.1039/c7cy02106b
• Languages: English
• ISSNs: 2044-4753

Abstract

Abstract : The Pd-Ni2P/SAPO-31 catalyst shows excellent performance in n -hexadecane hydroisomerization due to the synergistic effects of Pd–Ni2P and improved metal/acid balance. Abstract : A series of bifunctional catalysts are prepared by loading Pd, Ni2 P and bimetallic Pd–Ni2 P on di- n -butylamine(DBA)-templated SAPO-31 molecular sieves through either impregnation or impregnation combined with temperature-programmed reduction methods. All bifunctional catalysts are characterized using XRD, N2 adsorption, 27 Al and 31 P MAS NMR, SEM, TEM, IR spectroscopy of adsorbed pyridine, XPS, H2 chemisorption, ICP, and TG–DTG measurements. The catalytic performance over all prepared bifunctional catalysts is compared for n -hexadecane hydroisomerization. The obtained results demonstrate that the 0.05Pd–4Ni2 P/S31 catalyst produces a higher iso-C16 yield of 72.7% with n -C16 conversion of 83.1% compared with the other two catalysts. This result is attributed to two reasons: i) the bimetallic Pd–Ni2 P component possesses stronger (de)hydrogenation functionality than Ni2 P does, and ii) the bimetallic bifunctional catalyst has a better balance between metal and acid functionality than the monometallic catalysts do. Moreover, the 0.05Pd–4Ni2 P/S31 catalyst also shows the best catalytic stability among all catalysts, since the n -C16 conversion and iso-C16 selectivity are still above 80% and 90%, respectively, even after 100 h of long-term testing. Therefore, the present study has provided a novel idea for the design of bimetallic bifunctional catalysts for long-chain n -alkane hydroisomerization.