Influence of preparative method on Al2O3-doped Pt/WO3-ZrO2 catalyst for n-heptane isomerization

Abstract

Alumina-doped Pt/WO3/ZrO2 catalysts were prepared using either a constant or variable pH method. The obtained catalyst samples were characterized using N2 adsorption, X-ray diffraction, ultraviolet-visible diffuse reflectance, CO chemisorption, X-ray photoelectron spectroscopy, 27 Al magic-angle spinning nuclear magnetic resonance, and infrared spectroscopy of adsorbed pyridine. Compared to the catalyst prepared using the variable pH method, the catalyst prepared using the constant pH method had a higher surface area and Pt dispersion. More Brönsted acid sites were generated in the presence of H2 on the latter catalyst, and this was responsible for its higher catalytic activity in n-heptane hydroisomerization. When the reaction temperature was 200 °C and the weight hourly space velocity of n-heptane was 0.9 h-1 , the Pt/WO3/Al2O3-ZrO2 catalyst prepared using the constant pH method gave 70.0% conversion of n-heptane, which was significantly greater than the conversion obtained using the corresponding catalyst prepared using the variable pH method (43.5%).

Performance of RP-3 kerosene cracking over Pt/WO3–ZrO2 catalyst

“…It is worth noting that WO 3 -ZrO 2 composite oxides can not only keep the special properties of the WO 3 and ZrO 2 but also can overcome the shortcomings of single WO 3 and ZrO 2 . For this reason, WO 3 -ZrO 2 composite oxides have attracted great attention in recent years and have already been applied in various fields, such as benzene alkylation with 1-hexane [19], the adsorption of hydrogen [20], the esterification reaction [21], the high temperature selective catalytic reduction applications [22], synthesis of acetyl salicylic acid [23], thiolation of dimethyl sulfide to methanethiol [24], and the isomerization reaction of straight chain paraffin [25]. Nevertheless, the use of WO 3 -ZrO 2 composite oxides as support for the kerosene pyrolysis has been seldom addressed.…”

Dimensional Effect on Self-Sustaining Catalytic Combustion of n-Heptane in Micro/Meso Tubes

“…18 The conversion and selectivity of isomerization can reach over 70 and 98%, respectively, on the Pt/WAZ catalyst at 200 °C and n(H 2 )/n(heptane) = 27:1. 19 During the n-heptane isomerization on Pt/HZSM-5, cracking selectivity increases with the temperature and reaches up to 40% at 350 °C. 20 The catalytic reactions at 500 °C under N 2 over fresh ZSM-5 with V 2 O 5 /Al 2 O 3 generate butylene, propane, propylene, and butane as the main products of n-heptane cracking.…”

“…The apparent activation energy of isomerization is much lower than that of cracking at 150–250 °C. , The results of n -heptane reforming over Pt/Al–HMS showed the selectivity of isoheptane, and hydrocracking decreased as the reaction temperature increased . The conversion and selectivity of isomerization can reach over 70 and 98%, respectively, on the Pt/WAZ catalyst at 200 °C and n (H 2 )/ n (heptane) = 27:1 . During the n -heptane isomerization on Pt/HZSM-5, cracking selectivity increases with the temperature and reaches up to 40% at 350 °C .…”

Bulk and surface characterization and isomerization activity of Pt/WO4 2−/ZrO2 catalysts of different preparations

“…Tungstated zirconia based catalysts for the isomerization of heavier paraffins are of particular interest [6,[14][15][16][17][18][19][20]. They exhibit catalytic activity slightly lower than that of sulfated zirconia based catalysts, but have greater isomerization selectivity [2,3,21].…”