Suppression of platinum sintering on Pt–M/ZSM-22 (M = Ce, La, and Re) catalyst for<i>n</i>-dodecane isomerization

Ning, Qian; Zhang, Huaike; He, Yurong; Chen, Zhiqiang; Liu, Suyao; Ren, Jie

doi:10.1039/c9nj03194d

Cited by 18 publications

(13 citation statements)

References 59 publications

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“…Ni mainly existed as Ni 0 , which availed sufficient metal sites for the hydrogenation reaction to alleviate the coking of the catalyst during the reaction . A small amount of Ni 2+ might exist because the unique electron transfer produced Ni and afforded positively charged electrons to the surface as Ni 2+ , when Ni interacted with CeO 2 . , …”

Section: Resultsmentioning

confidence: 99%

“…Thus, they are being gradually replaced by transition and rare-earth metals, such as Ni, Mo, Cu, W, La, and Ce. − Wang et al believed that the catalyst life could be significantly increased by loading Ni–Mo or Ni–La on HMOR. Ning et al . indicated that the introduction of Ce could effectively inhibit the aggregation of Pt during the isomerization of n -dodecane.…”

Section: Introductionmentioning

confidence: 99%

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Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Cao

Wang

et al. 2021

ACS Omega

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The catalytic performance of the selective isomerization of oethyltoluene (O-ET) is crucial to increasing the m-ethyltoluene (M-ET) and pethyltoluene (P-ET) yields. During the isomerization of O-ET, traditional (commercial) mordenites (HM) are generally limited by a high reaction temperature (235 °C), as well as a low yield of the isomerization product (49.0%). In this study, micro-mesoporous mordenites were obtained by treating commercial mordenites with NaOH, NaOH−HNO 3 , and NaOH−mixed acid (HNO 3 −oxalic). Thereafter, their structure, porosity, and acidity were investigated via X-ray diffraction, transmission electron microscopy, inductively coupled plasma, N 2 sorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy of pyridine, temperature-programmed desorption of ammonia, and nuclear magnetic resonance. Among the various treated samples, the accessibility of the acidic sites and the B/L value of the alkali− mixed HNO 3 −oxalic one were enhanced, achieving the highest yield (53.6%) and lowest reaction temperature (165 °C), thus significantly reducing the energy consumption of the reaction process. Furthermore, Ni and Ce were successfully loaded via the incipient wetness impregnation of the micro-mesoporous mordenite to significantly prolong the catalytic life. This study affords a new strategy for obtaining high M-ET and P-ET yields from the isomerization of O-ET in mixed C 9 aromatics on an industrial scale.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Cao

Wang

et al. 2021

ACS Omega

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“…The XPS spectra of the prepared catalysts are shown in Figure 7 . The Al 2p peaks (centred at 73.9 eV) are located in the range of 79–67 eV, which were separated from these spectra [ 39 , 40 ]. The obtained Pt 4f 7/2 spectra were deconvoluted into two peaks centred at 70.1 and 71.0 eV, and the Pt 4f 5/2 spectra were deconvoluted into two peaks centred at 73.4 and 74.3 eV as shown in Table 3 .…”

Section: Resultsmentioning

confidence: 99%

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

et al. 2020

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Herein, Pt/HZSM-5 zeolite catalysts with different crystallite sizes ranging from nanosheet (~2 nm) to bulk crystals (~1.5 μm) have been prepared for the hydrodeoxygenation of guaiacol, and their effects on the reaction pathway and product selectivity were explored. HZSM-5 zeolites prepared by seeding (Pt/Z-40: ~40 nm) or templating (Pt/NS-2: ~2 nm) fabricated intra-crystalline mesopores and thus enhanced the reaction rate by promoting the diffusion of various molecules, especially the bulky ones such as guaiacol and 2-methoxycyclohexanol, leading to a higher cyclohexane selectivity of up to 80 wt % (both for Pt/Z-40 and Pt/NS-2) compared to 70 wt % for bulky HZSM-5 (Pt/CZ: ~1.5 μm) at 250 °C and 120 min. Furthermore, decreased crystallite sizes more effectively promoted the dispersion of Pt particles than bulky HZSM-5 (Pt/Z-400: ~400 nm and Pt/CZ). The relatively low distance between Pt and acidic sites on the Pt/Z-40 catalyst enhanced the metal/support interaction and induced the reaction between the guaiacol molecules adsorbed on the acidic sites and the metal-activated hydrogen species, which was found more favorable for deoxygenation than for hydrogenation of oxygen-containing molecules. In addition, Pt/NS-2 catalyst with a highly exposed surface facilitated more diverse reaction pathways such as alkyl transfer and isomerization.

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“…Zeolites, especially those with acidic properties, find wide applications as catalysts and supports for metal catalysts. Examples are faujasites containing platinum, used for processes such as alkane hydrocracking and hydroisomerization, − and zeolite Beta and chabazite containing iron and copper, used for vehicle exhaust abatement. − The metals in these catalysts are typically highly dispersed to maximize their accessibility to reactants. The most highly dispersedatomically dispersedmetals are drawing wide attention because they maximize the number of metal atoms engaged in catalysis and have properties different from those of metals present in nanoparticles, the commonly applied form of supported metals …”

Section: Introductionmentioning

confidence: 99%

Isostructural Atomically Dispersed Rhodium Catalysts Supported on SAPO-37 and on HY Zeolite

Perez-Aguilar

Chen

Hughes³

et al. 2020

J. Am. Chem. Soc.

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Zeolites are widely applied supports for metal catalysts, but molecular sieves with comparable structuressilicoaluminophosphates (SAPOs)have drawn much less attention and been overlooked as supports for atomically dispersed metals. Now, we report SAPO-37 as a support for atomically dispersed rhodium in rhodium diethylene complexes, made by the reaction of Rh(η2-C2H4)2(acetylacetonate) with the support and anchored by two Rh–O bonds at framework tetrahedral sites, as shown by infrared and extended X-ray absorption fine structure spectra. The ethylene ligands were readily replaced with CO, giving sharp νCO bands indicating highly uniform supported species. A comparison of the spectra with those of comparable rhodium complexes on zeolite HY shows that the SAPO- and zeolite-supported complexes are isostructural, providing an unmatched opportunity for determining support effects in catalysis. The two catalysts had similar initial room-temperature activities per Rh atom for ethylene conversion in the presence of H2, but the SAPO-supported catalyst was selective for ethylene hydrogenation and the zeolite-supported catalyst selective for ethylene dimerization; correspondingly, the catalyst on the SAPO was more stable than that on the zeolite during operation in a flow reactor.

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Suppression of platinum sintering on Pt–M/ZSM-22 (M = Ce, La, and Re) catalyst forn-dodecane isomerization

Abstract: Ce-modified Pt/ZSM-22 catalyst with slightly increased acidity and electron-deficient Pt exhibits improved isomer selectivity and sintering resistance of Pt in n-dodecane isomerization.

Cited by 18 publications

References 59 publications

Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Enhancing the Catalytic Properties of Mordenites via an Alkali–Acid Treatment and by Loading Nickel–Cerium during o-Ethyltoluene Isomerization

Effects of Crystallite Sizes of Pt/HZSM-5 Zeolite Catalysts on the Hydrodeoxygenation of Guaiacol

Isostructural Atomically Dispersed Rhodium Catalysts Supported on SAPO-37 and on HY Zeolite

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