Effect of Titania Grafting on Behavior of NiMo HDS Catalysts Supported on Nanostructured Silica Materials

2012 ◽  
Vol 1371 ◽  
Author(s):  
A. Mendoza-Nieto ◽  
I. Puente-Lee ◽  
C. Salcedo-Luna ◽  
T. Klimova
Keyword(s):  
Total Pore Volume ◽  
Bet Surface Area ◽  
Silica Supports ◽  
Metal Support Interaction ◽  
Silica Materials ◽  
Hds Catalysts ◽  
Metal Support ◽  
Nimo Catalysts ◽  
Nanostructured Silica ◽  
Mcm 41

ABSTRACTIn the present work, a comparison study of the NiMo hydrodesulfurization (HDS) catalysts supported on different nanostructured supports of MCM-41 and SBA-15-types and the same ones modified by TiO2 grafting was undertaken. The aim of this study was to inquire on the effect of the characteristics of the primary silica supports on the activity and selectivity of the NiMo catalysts modified with titania in deep HDS. Supports and catalysts were characterized by nitrogen physisorption, small-angle and powder XRD, TPR, UV-vis DRS, and HRTEM, and tested in the simultaneous HDS of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). It was found that titania grafting on all silica supports resulted in a slight decrease of BET surface area and total pore volume. However, the characteristic p6mm hexagonal pore arrangement of the used nanostructured silica materials was not affected. Powder X-ray diffraction pointed out a good dispersion of Mo and Ni oxide species in all prepared catalysts. TPR characterization of the NiMo catalysts revealed some increase in the metal-support interaction after titania grafting on the silica surface. Further DRS characterization indicated that the best dispersion of Mo oxide species was obtained on the TiSBA-15 support. Titania addition to the silica supports also produced an increase in the dispersion of the sulfided NiMo phase, which was more marked for SBA-15 support than for the MCM-41 (HRTEM). The most active NiMo/Ti-SBA-15 catalyst resulted to be significantly more active (∼40 %) than the conventional NiMo/γ-Al2O3 catalyst in HDS of 4,6-DMDBT.

Tuning the metal–support interaction in supported K-promoted NiMo catalysts for enhanced selectivity and productivity towards higher alcohols in CO hydrogenation

2017 ◽  
Vol 7 (18) ◽  
pp. 4206-4215 ◽  
Author(s):  
Jiaxi Yong ◽  
Xuebin Luan ◽  
Xiaoping Dai ◽  
Xin Zhang ◽  
Hongyan Qiao ◽  
...  
Keyword(s):  
Co Hydrogenation ◽  
Higher Alcohols ◽  
Support Interaction ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Nimo Catalysts ◽  
Enhanced Selectivity

Ni–KMoS/MMO catalysts were obtained using encapsulated Mo-based precursors to tune metal–support interaction, and enhanced selectivity and productivity towards higher alcohols.

scholarly journals Synthesis of Hydrophobic Mesoporous Material MFS and Its Adsorption Properties of Water Vapor

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Guotao Zhao ◽  
Zhenxiao Zhao ◽  
Junliang Wu ◽  
Daiqi Ye
Keyword(s):  
Water Vapor ◽  
Surface Area ◽  
Mesoporous Material ◽  
High Surface ◽  
Synthesis Method ◽  
Gravimetric Method ◽  
Total Pore Volume ◽  
Adsorption Properties ◽  
Bet Surface Area ◽  
Mcm 41

Fluorine-containing hydrophobic mesoporous material (MFS) with high surface area is successfully synthesized with hydrothermal synthesis method by using a perfluorinated surfactant SURFLON S-386 template. The adsorption properties of water vapor on the synthesized MFS are also investigated by using gravimetric method. Results show that SEM image of the MFS depicted roundish morphology with the average crystal size of 1-2 μm. The BET surface area and total pore volume of the MFS are 865.4 m2 g−1and 0.74 cm3 g−1with a narrow pore size distribution at 4.9 nm. The amount of water vapor on the MFS is about 0.41 mmol g−1at 303 K, which is only 52.6% and 55.4% of MCM-41 and SBA-15 under the similar conditions, separately. The isosteric adsorption heat of water on the MFS is gradually about 27.0–19.8 kJ mol−1, which decreases as the absorbed water vapor amount increases. The value is much smaller than that on MCM-41 and SBA-15. Therefore, the MFS shows more hydrophobic surface properties than the MCM-41 and SBA-15. It may be a kind of good candidate for adsorption of large molecule and catalyst carrier with high moisture resistance.

scholarly journals Simple Synthesis and Characterization of Hexagonal and Ordered Al–MCM–41 from Natural Perlite

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 264 ◽  
Author(s):  
Hongyun Chen ◽  
Siyao Fu ◽  
Liangjie Fu ◽  
Huaming Yang ◽  
Deliang Chen
Keyword(s):  
Mesoporous Silica ◽  
Bet Surface Area ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Structures ◽  
Ordered Mesoporous ◽  
Silica Materials ◽  
Mesoporous Silica Materials ◽  
Mcm 41

Silica reagents are expensive and toxic for use in the synthesis of mesoporous silica materials. It is imperative to take an interest in green silicon sources. In this paper, we report the synthesis of hexagonal and ordered aluminum-containing mesoporous silica materials (Al–MCM–41) from natural perlite mineral without addition of silica or aluminum reagents. A pretreatment process involving acid leaching, alkali leaching, and strongly acidic cation exchange resins treatment was critical to obtain silicon and aluminum sources from natural perlite mineral. The Al–MCM–41 material was synthesized via a hydrothermal reaction with hexadecyl trimethyl ammonium bromide (CTAB) as the template and subsequent calcination. The resulting mesophase had a hexagonal and ordered mesoporous structure, confirmed by small-angle X-ray diffraction (SAXRD) and transmission electron microscopy (TEM). Al–MCM–41 material had a high Brunauer–Emmet–Teller (BET) surface area of 1024 m2/g, pore volume of 0.72 cm3/g and an average pore diameter of 2.8 nm with a pore size distribution centered at 2.5 nm. The thermal behavior of the as-synthesized samples during calcination was investigated by thermogravimetry (TG) and differential thermogravimetry (DTG) analysis. The Al–MCM–41 material showed a negative surface charge in aqueous solution with the pH value ranging from 2 to 13. The variations of chemical structures from natural perlite to Al–MCM–41 were traced by wide-angle X-ray diffraction (WAXRD) and Fourier-transform infrared spectroscopy (FTIR). A proposed mechanism for the synthesis of hexagonal and ordered mesoporous silica materials from natural perlite is discussed.

scholarly journals Hydrodesulfurization of 4,6-Dimethyldibenzothiophene and the Diesel Oil Fraction on NiMo Catalysts Supported over Proton-Exchanged AlMCM-41 and TiMCM-41 Extrudates

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1086
Author(s):  
Karolina Jaroszewska ◽  
Marek Lewandowski ◽  
Kinga Góra-Marek ◽  
Jolanta Grzechowiak ◽  
Gérald Djéga-Mariadassou
Keyword(s):  
Catalytic Efficiency ◽  
Active Phase ◽  
Order Rate Constant ◽  
Diesel Oil ◽  
High Dispersion ◽  
Catalytic Systems ◽  
Oil Fraction ◽  
Metal Support Interaction ◽  
Nimo Catalysts ◽  
Mcm 41

NiMo catalysts supported on mesoporous MCM-41 type materials shaped with binder were tested for activity in the hydrodesulfurization of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and the diesel fuel fraction (0.92 wt% of sulfur). The aim of the investigation was to evaluate the effect of ion exchange with protons of Al- or Ti-substituted MCM-41 mesoporous supports. The subjected catalytic systems were NiMo/HAlMCM-41 and NiMo/HTiMCM-41, and for comparison purposes NiMo/AlMCM-41 and NiMo/TiMCM-41. The samples were characterized by N2 sorption (at 77 K), XRD, TEM, XPS, SEM and Py–IR. It was found that the functionalization of AlMCM-41 and TiMCM-41 with protons increased the conversion of 4,6-DMDBT and the pseudo-first-order rate constant. Correspondingly, 4,6-DMDBT HDS reactions over the NiMo/HTiMCM-41 catalyst proceeded to a similar extent via hydrogenation and direct desulfurization, whereas over the NiMo/HAlMCM-41 they proceeded mainly via direct desulfurization. Furthermore, the ion-exchanged catalysts displayed two-fold higher efficiency in direct desulfurization than their non-modified counterparts. The NiMo/HTiMCM-41 catalyst exhibited the highest catalytic efficiency in the HDS of 4,6-DMDBT and the diesel oil fraction. The high activity of the NiMo/HTiMCM-41 catalyst is mainly attributed to its appropriate acidity, as well as the metal–support interaction providing both the high dispersion of the active phase and the desirable multilayered stacking morphology of the active phase slabs.

Preparation and Characterization of Advanced PtRu/Ti0.7Mo0.7O2 Catalysts for Direct Methanol Fuel Cells

2018 ◽  
Vol 876 ◽  
pp. 57-63 ◽  
Author(s):  
Van Thi Thanh Ho ◽  
Long Giang Bach ◽  
Dai Viet Nguyen Vo
Keyword(s):  
High Performance ◽  
Direct Methanol Fuel Cells ◽  
Average Particle Size ◽  
Structural Features ◽  
Bet Surface Area ◽  
Average Particle ◽  
Carbon Corrosion ◽  
Alloy Particles ◽  
Metal Support Interaction ◽  
Metal Support

We report the new strategy by investigating the novel Ti0.7Mo0.3O2material can just as easily be used as a conductive support for PtRu for DMFCs to prevent not only the carbon corrosion but also improved activity of catalyst due to some functional advantages of novel Ti0.7Mo0.3O2support. The Ti0.7Mo0.3O2nanoparticle have good crystallinity with well-defined fringes corresponding to the 3.45 Å spacing value of the {101} plane of anatase TiO2, which were good according to the XRD pattern. The BET surface area measurements showed that the Ti0.7Mo0.3O2possessed 125 m2g-1Fig. 3 shows the TEM measurement of Ti0.7Mo0.3O2nanoparticle and Pt/Ti0.7Mo0.3O2, it can be observed that spherical PtRu alloy particles with an average particle size of 2-4 nm were uniformly anchored on the surface of Ti0.7Mo0.3O2support. More importantly, we found that there has a strong metal support interaction (SMSI) between the PtRu noble metal and the Ti0.7Mo0.3O2support material - resulting in facile electron donation from the Ti0.7Mo0.3O2support to PtRu metal with an ultimate drastic decrease in the d-band vacancy of Pt. Thus, the unique structural features of the Ti0.7Mo0.3O2support and the PtRu/Ti0.7Mo0.3O2catalyst appear to provide a suitable combination favoring that promise for the high performance of methanol oxidation, CO-tolerance in DMFCs.

scholarly journals Experimental and computational study on roles of WOx promoting strong metal support promoter interaction in Pt catalysts during glycerol hydrogenolysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tinnakorn Saelee ◽  
Poonnapa Limsoonthakul ◽  
Phakaorn Aphichoksiri ◽  
Meena Rittiruam ◽  
Mongkol Lerdpongsiripaisarn ◽  
...  
Keyword(s):  
Density Of States ◽  
Design Guidelines ◽  
Total Density ◽  
High Electron ◽  
Metal Support Interaction ◽  
Metal Support ◽  
Glycerol Hydrogenolysis ◽  
The Stability ◽  
Total Density Of States ◽  
Promoter Interaction

AbstractBiodiesel is of high interest due to increased demand for energy with the concern regarding more sustainable production processes. However, an inevitable by-product is glycerol. Hence, the conversion of this by-product to higher-value chemicals, especially 1,3-propanediol (1,3-PDO) via glycerol hydrogenolysis reaction, is one of the most effective pathways towards a profitable process. In general, this process is catalyzed by a highly active Pt-based catalyst supported on γ-Al2O3. However, its low 1,3-PDO selectivity and stability due to surface deactivation of such catalysts remained. This led to the surface modification by WOx to improve both the selectivity by means of the increased Brønsted acidity and the stability in terms of Pt leaching-resistance. Hence, we applied experimental and density functional theory (DFT)-based techniques to study the fundamentals of how WOx modified the catalytic performance in the Pt/γ-Al2O3 catalyst and provided design guidelines. The effects of WOx promoter on improved activity were due to the shifting of the total density of states towards the antibonding region evident by the total density of states (TDOS) profile. On the improved 1,3-PDO selectivity, the main reason was the increasing number of Brønsted acid sites due to the added WOx promoter. Interestingly, the stability improvement was due to the strong metal-support interaction (SMSI) that occurred in the catalyst, like typical high leaching-resistant catalysts. Also, the observed strong metal-support-promoter interaction (SMSPI) is an additional effect preventing leaching. The SMSPI stemmed from additional bonding between the WOx species and the Pt active site, which significantly strengthened Pt adsorption to support and a high electron transfer from both Pt and Al2O3 to WOx promoter. This suggested that the promising promoter for our reaction performed in the liquid phase would improve the stability if SMSI occurred, where the special case of the WOx promoter would even highly improve the stability through SMSPI. Nevertheless, various promoters that can promote SMSPI need investigations.

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