“…The dispersion of the metal atom groups and metal cluster sizes on the 1% Pt/SBA-15 catalysts can be seen in Figure 6 , which are also shown in Table 1 . The metal clusters are better distributed in the TEM image, which is in agreement with the literature [ 44 ], resulting in a larger surface area on which the reactions can occur. Figure 6 TEM images of (A) SBA-15 and (b) 1% Pt-SBA-15.…”
Section: Resultssupporting
confidence: 90%
“…Throughout the reaction process for isomerization over catalysts with dual functions, zeolite Brønsted acid sites contributed to the process of transforming alkenes in the intermediate state into structural isomers throughout the isomerization process on bifunctional catalysts. Both hydrocracking and dehydrogenation are possible without the presence of these acidic sites, just as they occur on SBA-15 [ 44 ]. Because the 1% Pt/SBA-15 catalyst pores are considerably larger, they have little selectivity for products of isomerization and are therefore are not product selective.…”
“…The dispersion of the metal atom groups and metal cluster sizes on the 1% Pt/SBA-15 catalysts can be seen in Figure 6 , which are also shown in Table 1 . The metal clusters are better distributed in the TEM image, which is in agreement with the literature [ 44 ], resulting in a larger surface area on which the reactions can occur. Figure 6 TEM images of (A) SBA-15 and (b) 1% Pt-SBA-15.…”
Section: Resultssupporting
confidence: 90%
“…Throughout the reaction process for isomerization over catalysts with dual functions, zeolite Brønsted acid sites contributed to the process of transforming alkenes in the intermediate state into structural isomers throughout the isomerization process on bifunctional catalysts. Both hydrocracking and dehydrogenation are possible without the presence of these acidic sites, just as they occur on SBA-15 [ 44 ]. Because the 1% Pt/SBA-15 catalyst pores are considerably larger, they have little selectivity for products of isomerization and are therefore are not product selective.…”
“…Another issue that should be taken into account is the presence of secondary mesopores within the zeolite phase in AlSBA-15-zeolite composite. As was presented earlier in our work [75] the method of preparation of AlSBA-zeolite supports developed by us has the advantage of creating mesopores not only in the AlSBA-15 phase but also in the zeolite phase. It appears that the formation of some kind micropore-mesopore continuity in Pt/SBA-BEA composite may explain their high hydroisomerization efficiency.…”
Section: Effect Of the Type Of Zeolite Incorporated To Pt/alsba-15-zeolitementioning
Hierarchical AlSBA-15–zeolite materials were utilized as a supports for preparing hydroisomerization catalysts. Detailed consideration was given to: (i) the effect of the zeolite type introduced into AlSBA-15–zeolite composites (where zeolite is β, mordenite or ZSM-5) as well as (ii) the promotion effect of Pd addition. The composites showed higher activity in isomerization as compared to Pt/AlSBA-15. The enhanced isomerization efficiency were explained by the appropriate metallic and acidic function as well as suitable transport properties. The modification of the hydrogenating function by Pd incorporation increases the hydroisomerization efficiency of Pt-Pd/AlSBA-15–β catalyst. Over bimetallic Pt-Pd/AlSBA-15–β, the high yields of isomers (68 wt%) with respect to 50 wt% for a control catalyst. The most promising Pt-Pd/AlSBA-15–β catalyst allows to improve research octane number from 0 to the 74 value.
“…Hydroisomerization is a technique to convert linear n-alkanes to their isomers, and it is a crucial component of the petroleum processing industry (Jin et al 2009;Qin et al 2011;Chi et al 2013;Wen et al 2017;Güleç et al 2019;Jaroszewska et al 2019). The hydroisomerization of n-alkanes can improve the quality of oil, such as decreasing the diesel pour point, enhancing the lubricant cold flow property and increasing the octane number of gasoline (Gomes et al 2017;Belinskaya et al 2019).…”
To enhance the gasoline octane number, low-octane linear n-alkanes should be converted into their high-octane di-branched isomers via n-alkane hydroisomerization. Therefore, hierarchical SAPO-11-based catalysts are prepared by adding different contents of sodium dodecylbenzene sulfonate (SDBS), and they are applied in n-nonane hydroisomerization. When n(SDBS)/n(SiO2) is less than or equal to 0.125, the synthesized hierarchical molecular sieves are all pure SAPO-11, and as the SDBS content increases, the submicron particle size decreases, and the external surface area (ESA) increases. Additionally, these hierarchical SAPO-11 have smaller submicron particles and higher ESA values than conventional SAPO-11. When n(SDBS)/n(SiO2) is greater than 0.125, with increasing SDBS content (n(SDBS)/n(SiO2) = 0.25), the synthesized SAPO-11 contains amorphous materials, which leads to a decline in the ESA; with the further increase in SDBS content (n(SDBS)/n(SiO2) = 0.5), the products are all amorphous materials. These results indicate that in the case of n(SDBS)/n(SiO2) = 0.125, the synthesized SAPO-11 molecular sieve (S–S3) has the most external Brønsted acid centers and the highest ESA of these SAPO-11, and these advantages favor generation of the di-branched isomers in hydrocarbon hydroisomerization. Among these Pt/SAPO-11 catalysts, Pt/S–S3 displays the highest selectivity to entire isomers (83.4%), the highest selectivity to di-branched isomers (28.1%) and the minimum hydrocracking selectivity (15.7%) in n-nonane hydroisomerization.
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