Boosting catalytic performance via electron transfer effect for hydroisomerization on a low-Pt-content PtCeOX/zeolite catalyst

摘要

Noble metal-acid bifunctional catalysts are widely used in important chemical processes such as hydroisomerization, reforming, and dehydrogenation to produce clean energy and high value-added chemicals. To boost the catalytic performance by preciously modulating the property of metal function along with reducing the noble metal loadings remains a great challenge. We herein report a highly efficient PtCeOx/ZSM-22 catalyst with low Pt amount (0.3 wt Pt) for n-paraffin hydroisomerization. The catalyst offers a high isomer selectivity (96) at an n-dodecane conversion of 91, which is superior to the conventional Pt/ZSM-22 catalyst with high Pt loadings. The combination of HAADF-STEM, CO-FT-IR, Raman, XAFS, and in situ XPS results reveals the structural feature of Pt anchored on ceria for the catalyst, and the electron transfer effect between Pt~(δ+) and CeOX. Benefiting from the electron transfer effect, the branched carbocations are rapidly formed in the reaction and high-selectively converted to target i-alkanes instead of cracking products.