Highly dispersed uniformly sized Pt nanoparticles on mesoporous Al-SBA-15 by solid state impregnation

Medina-Mendoza, A.K.; Cortés-Jácome, M.A.; Toledo-Antonio, J.A.; Ángeles–Chávez, C.; López-Salinas, E.; Cuauhtémoc-López, I.; Barrera, María C.; Escobar, José; Navarrete, Juan T. López; Hernández, I.

doi:10.1016/j.apcatb.2011.04.031

Cited by 20 publications

(23 citation statements)

References 92 publications

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“…The support properties prove important for the dispersion of Pt sites, such as the surface properties, porous structures, or surface defect types . Pt loading is also a critical factor, including Pt precursor,, loaded amount, and loading method ,. Strengthening the Pt‐support interactions helps improving Pt dispersion as well .…”

Section: Figurementioning

confidence: 99%

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

Zhu

et al. 2016

ChemCatChem

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Pseudo-single atom Pt catalysts have achieved an excellent selectivity to branched paraffins and cycloalkanesi nn-hexaner eforming here. Highly dispersed platinum in single-atom and small clusters made up of severals eparated atoms wasp roduced under the inducemento fSno rZ ra sp romoting components. The Sn or Zr oxides were topologically transformed from layered double hydroxides as precursors, and thus homogeneouslyd ispersed owing to the confinemento ft he brucitelike lattices. The lattice confinementa lso caused the promoter sites charge-transferred, affording electron-rich (Sn) or electron-defected (Zr) sites on the surface, therebyf acilitating the inducement to Pt sites. This strategy provides an effective and feasible alternative for the facile preparation of highly dispersed metal catalysts. In n-hexane reforming, as electivity of up to 95 %t ob ranched paraffins and cycloalkanesw as obtained with the pseudo-single-atomPtcatalysts.The catalytic reforming of straight-chain paraffin to branched paraffin and/orc ycloalkanesi samajor petroleum refining process for the production of high-octaneg asoline. The hydrogenolysis byproducts, however,n eed to be avoided for the atomeconomy.[1] The aromatic compounds are also undesired, as environmental regulations limit the carcinogenic components in gasoline.[2] The reformingp rocess is industrially accomplished by use of supported platinum catalysts.[3] It is critical to enhance the dispersiono fP ta toms for sake of product selectivity.[1b, 4] Large Pt ensemblesh ave been found to be active for the hydrogenolysis to form C1-C5 [5] by the factor of a3Dstruc-ture, the so-called B5 sites.[5b] The 6-fold coordinated step-like sites favor the dehydrocyclization to produce aromatic compounds.[6] To improve Pt dispersion, many efforts have been made during the past decades. The support properties [7] prove important for the dispersiono fP ts ites, such as the surface properties, [7a] porouss tructures, [7b] or surfaced efectt ypes.[7c] Pt loading is also ac ritical factor, [8] including Pt precursor, [8a,b] loaded amount, [8b] and loading method. [8b,c] Strengthening the Pt-support interactions helps improving Pt dispersion as well. [9] The formation of an ew interaction (e.g. Pt-(ONa) x -SiO 2 )b ya ddition of sodium ion [9a] or an enhanced Pt-support interaction by addition of rare earth ions (e.g. Tm)[9b] has improved the dispersion of Pt to cluster size. Addition of Re, Sn, or Ge as promoter is especially efficacious because, in addition to altering the electron density of Pt, [10] the promoter component separates Pt atomsf rom large aggregates by forming Pt x Ma lloys [11] or Pt-promoter oxidesislands. [12] Recently,( pseudo)-single-atom noblem etal catalysts have attracted significant attention owing to their remarkable catalytic properties. [13][14][15][16][17][18] Ac atalystw ith Pt atoms completely exposed to MgO surface has been obtained through am ass-selected soft-landing technique, in which each Pt atom counts for CO oxidation.[13] Isolated A...

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Section: Figurementioning

confidence: 99%

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

Zhu

et al. 2016

ChemCatChem

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“…20 By controlling the pH value of the impregnation solution, the hydroxyl groups that bonding on oxide surface become protonated or deprotonated, thus become positively charged below a characteristic pH value or negatively charged above the characteristic pH value. It was reported that Pt-based catalysts prepared by strong electrostatic adsorption (SEA) method exhibited higher dispersion of Pt than those prepared by IM method.…”

Section: Introductionmentioning

confidence: 99%

A well fabricated PtSn/SiO₂ catalyst with enhanced synergy between Pt and Sn for acetic acid hydrogenation to ethanol

Zhang

Wang

et al. 2016

RSC Adv.

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This work reported a well-fabricated PtSn/SiO 2 catalyst prepared by a modified two-step sol-gel (MTSG) method. The adoption of strong electrostatic adsorption (SEA) and sol-gel (SG) method could give both a significantly high Pt dispersion and a large amount of Lewis acid sites. The homogenous distribution of Sn species could not only provide more opportunity for the Pt precursor to disperse on the support by forming Pt-(O-Sn^) y 2Ày analogous species, but also enhance the synergy between Pt and Sn species.Consequently, an excellent activity was achieved in the hydrogenation of acetic acid (AcOH) with a conversion of 100% and ethanol (EtOH) selectivity of 93%. Investigations on the effect of Sn/Pt molar ratio showed that the dispersion of Pt decreases obviously with the increasing Sn/Pt ratio due to the geometric or electronic effects caused by SnO x species. A balancing effect between Pt active sites and Lewis acid sites was found to be responsible for the superior catalytic performance in AcOH hydrogenation. Moreover, a parallel reaction path model was proposed for the hydrogenation of AcOH over PtSn/SiO 2 catalyst, in which ethanol and ethyl acetate (AcOEt) are formed competitively through the adsorbed ethoxy intermediate. † Electronic supplementary information (ESI) available: Fig. S1 shows the N 2 adsorption-desorption isotherms and pore size distribution of reduced catalysts. Fig. S2 displays the HAADF-STEM and EDX elemental-mapping images of the reduced PtSn1.6/SiO 2 -MTSG catalyst. Fig. S3 shows the TEM images of reduced PtSnx/SiO 2 -MTSG catalysts. Fig. S4 represents the deconvolution of the t about FTIR spectra of chemisorbed pyridine on reduced catalysts. Fig. S5 displays the hydrogenation performance of AcOH over PtSn1.6/SiO 2 -MTSG catalyst as a function of WHSV (AcOH) . Table S1 shows the tted results of H 2 -TPR experiments of catalysts. Table S2 displays the integral quantity of Lewis acid sites of reduced catalysts. Table S3 illustrates the hydrogenation performance of AcOH over PtSn1.6/SiO 2 -MTSG catalysts. See

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“…As is well known, a micelle of CTAB can form in aqueous solution as a result of the ordered uniform aggregation of its organic group. Acetylacetone (acac) ligand of Ni(acac) 2 can interact with the organic group of CTAB, and hence, the Ni(acac) 2 can enter the hydrophobic core of surfactant micelles. In other words, Ni species are encompassed by CTAB and grafted into micelles.…”

Section: Resultsmentioning

confidence: 99%

Facile in situ Encapsulation of Highly Dispersed Ni@MCM‐41 for the Trans‐Decalin Production from Hydrogenation of Naphthalene at Low Temperature

et al. 2019

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Ni@MCM‐41 catalyst that has uniformly distributed, highly dispersed Ni nanoparticles (about 2.3 nm) was designed and successfully synthesized by in situ encapsulation of Ni in the channels of MCM‐41. This catalyst exhibits excellent thermal stability and hydrogenation activity. Water insoluble nickel acetylacetonate (Ni(acac)2) was first dissolved aqueous solution of cetyltrimethyl ammonium bromide (CTAB) and encapsulated in micelles of CTAB. Sodium silicate was used as a silicon source to rapidly hydrolyze and then wrap on the micelle surface to synthesize the MCM‐41 zeolite. The MCM‐41 zeolite encapsulating Ni(acac)2 was synthesized within a short time (4 h) at 120 °C. Compared with conventional supported catalysts, thus 3 wt.% Ni@MCM‐41 has ultra‐small uniformly distributed Ni nanoparticles and exhibits improved activity for the hydrogenation of naphthalene to decalin at very low reaction temperatures. The TOF and the apparent activation energy of Ni@MCM‐41 and the conventional catalysts (Ni/MCM‐41 and Pt/MCM‐41) were evaluated and compared. And the catalysis mechanism was analyzed. Furthermore, this Ni@MCM‐41 catalyst offers an additional advantage of selectivity in decalin isomerization; 92 % trans‐decalin selectivity was achieved at a wide temperature range.

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Highly dispersed uniformly sized Pt nanoparticles on mesoporous Al-SBA-15 by solid state impregnation

Cited by 20 publications

References 92 publications

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

A well fabricated PtSn/SiO₂ catalyst with enhanced synergy between Pt and Sn for acetic acid hydrogenation to ethanol

Facile in situ Encapsulation of Highly Dispersed Ni@MCM‐41 for the Trans‐Decalin Production from Hydrogenation of Naphthalene at Low Temperature

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Highly dispersed uniformly sized Pt nanoparticles on mesoporous Al-SBA-15 by solid state impregnation

Cited by 20 publications

References 92 publications

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

Pseudo‐single‐atom Platinum Induced by the Promoter Confined in Brucite‐like Lattice for Catalytic Reforming

A well fabricated PtSn/SiO2 catalyst with enhanced synergy between Pt and Sn for acetic acid hydrogenation to ethanol

Facile in situ Encapsulation of Highly Dispersed Ni@MCM‐41 for the Trans‐Decalin Production from Hydrogenation of Naphthalene at Low Temperature

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Product

Resources

About

A well fabricated PtSn/SiO₂ catalyst with enhanced synergy between Pt and Sn for acetic acid hydrogenation to ethanol