Protonic Acid Sites Research Articles

Effect of the carbon surface chemistry on the metal speciation in Ru/C catalysts. Impact on the transformation of levulinic acid to γ-valerolactone

A set of Ru/C catalysts prepared using a commercial active carbon and a series of carbon materials derived from it (treatment in N2 flow, at 300, 600 or 900 °C that selectively removes surface oxygen complexes), of similar textural properties and different surface chemistry, were used, without reduction treatment, in the aqueous phase transformation of levulinic acid (LA) to γ-valerolactone (GVL) at 70 °C. The prepared Ru/C catalysts were active, being activity and selectivity strongly dependent on the support surface chemistry. It was confirmed that the supported Ru species became reduced under reaction conditions, and this process was more efficient in catalysts prepared with the heat treated supports, due to the different interactions created between Ru species and the support surface. In a cleaner carbon surface, the anchorage of the Ru species on carbon oxygen groups was limited, and they were more prone to be reduced and to move, forming more defined metallic structures. The carbon surface chemistry determined the Ru speciation (reduced and oxidized species), and the proportion of reduced Ru drived the H spill over process, which was related to the creation of protonic acid sites, proposed to be key point to explain the trend in selectivity to GVL.

Highly Active Cathode Achieved by Constructing Surface Proton Acid Sites through Electronic Regulation of Heteroatoms

Highly Active Cathode Achieved by Constructing Surface Proton Acid Sites through Electronic Regulation of Heteroatoms

PtNi-W/C with Atomically Dispersed Tungsten Sites Toward Boosted ORR in Proton Exchange Membrane Fuel Cell Devices

HighlightsA hybrid electrocatalyst consisting of PtNi-W alloy nanocrystals loaded on carbon surface with atomically dispersed W sites was realized.Single-atomic W formed protonic acid sites and established an extended proton transport network at the catalyst surface.Peak power density is enhanced by 64.4% compared to that with the commercial Pt/C catalyst in fuel cell as cathode at ultra-low loading of 0.05 mgPt cm−2.

Mechanistic studies of lower temperature isomerization of n-heptane over fibrous silica molybdenum catalyst

Platinum (Pt) inclusion on fibrous silica molybdenum (FSMO) and MoO3/KCC-1 catalysts has been prepared and utilized for the lower temperature (200–350 °C) catalytic isomerization of n-heptane. The impact of Pt inclusion towards the structure, morphology, and acid distribution of catalysts was characterized by XRD, FTIR, N2-physisorption, Py-IR, and H2-IR. Compared with MoO3/KCC-1, FSMO demonstrated superior MoO3 dispersion and amount of Lewis acid site associated with the in-situ synthesis technique. Although Pt inclusion slightly lessened acid sites due to inevitable partial coverage by the Pt cluster, the considerably higher amount of Lewis acid sites compared to Brønsted and conjugated sufficiently for generating protonic acid sites for enriching the isomerization activity. In contrast to Pt/MoO3/KCC-1 and undoped catalysts, Pt/FSMO achieved a superior conversion of 70.9% with 63.6% isomer yield at a low temperature of 250 °C. The 28-h stability tests demonstrated that Pt/FSMO recorded stable isomerization activity, with a superior isomer yield (∼48–52%) and inferior cracking yield (<3.0%) than Pt/MoO3/KCC-1.

Hydroisomerization of n-hexane over metal oxides-loaded fibrous silica catalyst for cleaner fuel production

Fibrous silica (KCC-1) was impregnated with cobalt (Co), iron (Fe), and zinc (Zn) oxides which are denoted as Co/KCC-1, Fe/KCC-1 and Zn/KCC-1 for hydroisomerization of n-hexane. The characterization analysis revealed that the introduction of Co, Fe, and Zn into KCC-1 significantly altered the physicochemical properties of KCC-1 including reduced surface area, pore volume as well as crystallinity. Pyridine adsorbed IR showed that higher amount of the Lewis acid sites (LAS) and Brønsted acid sites (BAS) when introduced the Co, Fe, and Zn into KCC-1. Interestingly, a new band at 1610 cm−1 of Zn/KCC-1, corresponds to the presence of LAS by the formation of binuclear species of Zn in the form of [ZnOZn]2+. The formation of [ZnOZn]2+ was further confirmed by the presence of a band at 350 nm and higher intensity of the binding energy at 1022.8 eV from UV-DRS and XPS analysis, respectively. From temperature-programmed reduction analysis, these binuclear species were formed at a higher temperature, which has a stronger interaction with the KCC-1. The proposed formation of [ZnOZn]2+ was also discussed in this work. Based on the n-hexane hydroisomerization, the Zn/KCC-1 possessed the most excellent catalytic performance amongst the catalysts owing to the existence of the binuclear species of [ZnOZn]2+, which acts as a new acidic center in the stabilization of generated protonic acid sites by trapping of electrons, resulting in increased isomers yield of n-hexane as well as no cracking products. Zn/KCC-1 showed the lowest activation energy compared to other catalysts within 423–673 K.

New insight into the mechanism of isomerization of C5–C7 alkanes over MoO3/FST

Molybdenum trioxide doped on fibrous silica-titania (MoO3/FST) has been synthesized and evaluated in the catalytic isomerization of C5–C7 for the first time. The structure characterization, functional group, and acid distribution of MoO3/FST were assessed via XRD, N2-physisorption, FTIR, and Py-IR analysis. The IR spectra revealed that MoO3/FST was occupied by a moderate-to-strong Brønsted and Lewis acid sites distribution. By adding MoO3, intense metal-support interactions were formed, lessening Brønsted acid sites' intensity in contrast to the increasing Lewis acid sites' intensity. The isomerization test demonstrated that maximum conversions of 50.0, 80.0, and 84.0% were acquired at 300 °C corresponding to n-C5, n-C6, and n-C7, respectively. As the isomerization temperature rose from 150 to 350 °C, the yield of n-C5 to n-C7 isomers increased to ∼70.0%. The high activity of MoO3/FST was ascribed to the effective interaction between MoO3 with perturbed silanol groups, which led to enrichment in protonic acid site formation via H2 spillover. This finding proves that the isomerization catalysts should possess great Lewis acid and Bronsted acid sites to enrich the protonic acid side, resulting in high performance in isomerization.

Molecular Routes of Dynamic Autocatalysis for Methanol-to-Hydrocarbons Reaction

The industrially important methanol-to-hydrocarbons (MTH) reaction is driven and sustained by autocatalysis in a dynamic and complex manner. Hitherto, the entire molecular routes and chemical nature of the autocatalytic network have not been well understood. Herein, with a multitechnique approach and multiscale analysis, we have obtained a full theoretical picture of the domino cascade of autocatalytic reaction network taking place on HZSM-5 zeolite. The autocatalytic reaction is demonstrated to be plausibly initiated by reacting dimethyl ether (DME) with the surface methoxy species (SMS) to generate the initial olefins, as evidenced by combining the kinetic analysis, in situ DRIFT spectroscopy, 2D 13C-13C MAS NMR, electronic states, and projected density of state (PDOS) analysis. This process is operando tracked and visualized at the picosecond time scale by advanced ab initio molecular dynamics (AIMD) simulations. The initial olefins ignite autocatalysis by building the first autocatalytic cycle-olefins-based cycle-followed by the speciation of methylcyclopentenyl (MCP) and aromatic cyclic active species. In doing so, the active sites accomplish the dynamic evolution from proton acid sites to supramolecular active centers that are experimentally identified with an ever-evolving and fluid feature. The olefins-guided and cyclic-species-guided catalytic cycles are interdependently linked to forge a previously unidentified hypercycle, being composed of one "selfish" autocatalytic cycle (i.e., olefins-based cycle with lighter olefins as autocatalysts for catalyzing the formation of olefins) and three cross-catalysis cycles (with olefinic, MCP, and aromatic species as autocatalysts for catalyzing each other's formation). The unraveled dynamic autocatalytic cycles/network would facilitate the catalyst design and process control for MTH technology.

On the Role of Protonic Acid Sites in Cu Loaded FAU31 Zeolite as a Catalyst for the Catalytic Transformation of Furfural to Furan.

The aim of the present paper is to study the speciation and the role of different active site types (copper species and Brønsted acid sites) in the direct synthesis of furan from furfural catalyzed by copper-exchanged FAU31 zeolite. Four series of samples were prepared by using different conditions of post-synthesis treatment, which exhibit none, one or two types of active sites. The catalysts were characterized by XRD, low-temperature sorption of nitrogen, SEM, H2-TPR, NMR and by means of IR spectroscopy with ammonia and CO sorption as probe molecules to assess the types of active sites. All catalyst underwent catalytic tests. The performed experiments allowed to propose the relation between the kind of active centers (Cu or Brønsted acid sites) and the type of detected products (2-metylfuran and furan) obtained in the studied reaction. It was found that the production of 2-methylfuran (in trace amounts) is determined by the presence of the redox-type centers, while the protonic acid sites are mainly responsible for the furan production and catalytic activity in the whole temperature range. All studied catalysts revealed very high susceptibility to coking due to polymerization of furfural.

Mechanisms of aromatization of dilute ethylene on HZSM-5 and on Zn/HZSM-5 catalysts

Catalysts with a Zn/H+ molar ratio ranging from 0 (H-ZSM5) to 1.8 (Zn/H-ZSM5), were prepared by wet impregnation from three commercial zeolites with Si/Al ratio of 15, 40 and 75. The texture, acidity and reactivity of the bifunctional catalysts were characterized by: N2, IR followed by adsorption of pyridine and NH3-TPD, and tested at 500 °C with low partial pressure of ethylene (PC2H4 = 0.005 MPa) and a high GHSV (ca 13,300 h−1).The intrinsic activity of protonic acid sites in ethylene transformation depends on their density or rather on the concentration of next nearest neighbours pairs of Al atoms. Brønsted acid pair sites converts ethylene into aromatics while isolated protonic site are almost inactive. Two apparent primary products were distinguished: iso-butene and propene, resulting from the oligomerization-cracking catalytic pool, followed at high conversion by the concomitant formation of alkanes and aromatics through hydrogen transfer.The deposition of Zn was achieved by wet impregnation of the nitrate precursor. The thermal decomposition of the ZnOH+ cation by calcination is a function of the fraction of Al atoms in the nearest neighbours. Three main species of Zn could be identified: i) oxo-binuclear Zn2+ cations (O−-Zn2+-O-Zn2+-O−), ii) mononuclear Zn2+ cations (O−-Zn2+-O− and iii) ZnO particles located on the external surface. These species were quantified from the residual Brønsted acid sites probed by pyridine. A correlation has been established: one neutralized protonic site generates one Zn Lewis acid sites which coordinates two pyridine molecules. The ethylene conversion is proportional to the concentration of oxo-binuclear Zn cations and mononuclear Zn cations only correlate with hydrogenation and hydrogenolysis of olefins, while bulk ZnO is inactive.A metallacyclic mechanism of ethylene aromatization involving cyclo-butyl-zinc species has been proposed accordingly.

N-Hexane hydroisomerization over Zr-modified bicontinuous lamellar silica mordenite supported Pt as highly selective catalyst: Molecular hydrogen generated protonic acid sites and optimization

Zr-modified bicontinuous lamellar silica mordenite supported Pt catalysts were synthesized using the zirconyl chloride oxahydrate as the precursor for Zr species by the incipient wetness impregnation method. The influence of zirconium loading on the properties of Zr-modified HM@KCC-1 catalysts for n-hexane isomerization were studied. The results of XRD and lattice structure from IR study indicated that increasing zirconium loading did not change the properties of catalysts. The IR study with pre-adsorbed 2,6-dimethylpyridine as a probe molecule affirmed that increasing zirconium loading could increase the Lewis acid sites. The generation of protonic acid sites which were active in n-hexane hydroisomerization was mainly from molecular hydrogen through a hydrogen spill-over mechanism as established by in situ-IR study. The results for the catalytic testing indicated that PtZr/HM@KCC-1 catalyst was highly selective in n-hexane hydroisomerization due to abundant permanent Lewis acid sites for its promotive effect in the generation of protonic acid sites. However, the incorporation of excessive zirconium amount up to 10 wt percent loading led to a decline in the amount of protonic acid sites generated, thus reduced the hydroisomerization performance in the process. The optimum conditions for hydroisomerization of n-hexane over Pt5Zr/HM@KCC-1 were reaction temperature of 293 °C, treatment temperature of 474 °C and F/W of 502 mL/g.min with the predicted value for isomer yield of 83.9%.

Hydroconversion of n-hexane over Pt-supported on fibrous silica mordenite catalysts: effect of transition metals on acidity and activity

The effect of incorporation of either Zr, Co, Mo or Zn on Pt/HFSM was investigated for the hydroconversion of n-hexane in a pulsed micro-reactor at a temperature range 423-623 K. The acidity of all the studied catalysts were investigated using pyridine adsorption and Fourier Transform Infrared Spectroscopy. The FTIR-pyridine study showed that the catalysts possessed different concentration and strength of both Lewis and Brønsted acid sites. It was revealed that the moderate acid sites distribution on PtZr/HFSM and PtZn/HFSM facilitated the isomerization of the intermediate hexene while the strong acid sites were selective towards cracking reaction. The trend for the bimetallic catalysts studied in n-hexane hydroisomerization is in the order: PtZr/HFSM>PtZn/HFSM>PtMo/HFSM>PtCo/HFSM. The highest activity for hydrocracking and hydrogenolysis were exhibited by PtMo/HFSM and PtCo/HFSM respectively. The PtZr/HFSM exhibited the highest hydroisomerization activity due to the moderate acidity and abundant Lewis acid sites capable of generating protonic acid sites by the hydrogen-spill over phenomena.

Influence of Nitrate and Phosphate on Silica Fibrous Beta Zeolite Framework for Enhanced Cyclic and Noncyclic Alkane Isomerization.

Phosphate and nitrate were loaded on silica BEA (P/HSi@BEA and N/HSi@BEA), which is fibrously protonated by the impregnation method for n-hexane and cyclohexane isomerization. The characterization analysis specified the removal of tetrahedral aluminum atoms in the framework, which was triggered by the existence of phosphate and nitrate groups in the catalyst. The exchanged role of Si(OH)Al to P-OH as active acidic sites in the P/HSi@BEA catalyst reduced its acidic strength, which was confirmed by the FTIR results. Lewis acidic sites of P/HSi@BEA performance are a significant part in the generation of high protonic acid sites, as proven by the in situ ESR study. However, FTIR evacuation and 27Al NMR revealed that the reduction in the amount of extraframework Al (EFAl) is due to its interaction with the nitrate group on the outside of the catalyst surface. The N/HSi@BEA catalyst exhibited high acidic strength because of the existence of more Si(OH)Al, which was initiated during the nitrate-incorporation process. Of significance is that the catalytic performance of n-hexane isomerization in the presence of hydrogen reached 50.3% product isomer yield at 250 °C, which might be ascribed to the presence of P-OH active sites that are responsible for accepting electrons, forming active protonic acid sites. NO3-EFAl interaction induced the formation of Brønsted acid sites, and higher mesopore volume favors the production of cyclohexane isomers up to 48.4% at 250 °C. This fundamental study exhibits that significant interactions given by such phosphate and nitrate groups with the unique silica fibrous BEA support could enhance isomerization, which contributes to the high quality of fuel.

Influence of zeolite crystal size on selective conversion of n-alkane: Controlling intermediates’ diffusion distances inside the micropores

In this work, the alkali-treatment with NaOH solution was used to reduce the crystal sizes of original zeolite Y. Acidic supports of two bifunctional catalysts consisted of γ-alumina binder and zeolite Y (original or alkali-treated) with different crystal size distributions. Most of metal platinum was selectively deposited on the γ-alumina component via the electrostatic adsorption method. Given the above, it can be deduced that (de)hydrogenation reaction occurred inside the zeolite micropores at a low probability, while active protonic acid sites catalyzing the skeletal conversions of alkene intermediates were exclusively located on zeolite Y. Therefore, the number of active protonic sites that intermediates potentially encountered between two metal sites can be regarded as being proportional to diffusion distances of intermediates within the zeolite micropore structures. Moreover, the above-mentioned diffusion distances were greatly associated with the zeolite crystal sizes. Isomerization reactions of n-decane (n-C10) on two bifunctional catalysts were investigated, and results indicated that the catalyst, with alkali-treated zeolite as the acidic component, performed better than the catalyst, for which original zeolite provided the acid function, in restraining the secondary reactions. This can be attributed to the shortened diffusion distances of intermediates inside the zeolite micropores, which was caused by reducing the zeolite crystal size.

Isomerization of linear C5–C7 over Pt loaded on protonated fibrous silica@Y zeolite (Pt/HSi@Y)

Abstract A novel fibrous silica Y zeolite (HSi@Y) loaded with Pt has been studied based on its ability to produce protonic acid sites originating from molecular hydrogen. The Pt/HSi@Y was prepared using seed assisted crystallization followed by protonation and Pt-loading. The product formed had a spherical morphology with bicontinuous lamellar with a diameter in the range of 500–700 nm. The catalytic activity of the Pt/HSi@Y has been assessed based on light linear alkane (C5–C7) isomerization in a micro-catalytic pulse reactor at 423–623 K. A pyridine IR study confirmed that the introduction of fibrous silica on Y zeolite increased the Lewis acid sites corresponding with the formation of extra-framework Al which led to the generation of more protonic acid sites. A hydrogen adsorbed IR study showed that the protonic acid sites which act as active sites in the isomerization were formed via dissociative-adsorption of molecular hydrogen releasing electrons to the nearby Lewis acid sites. Thus, it is suggested that the presence of Pt and HSi@Y with a high number of Lewis acid as well as weak Bronsted acid sites improved the activity and stability in C5, C6 and C7 isomerization via hydrogen spill-over mechanism.

Additional Lewis acid sites of protonated fibrous silica@BEA zeolite (HSi@BEA) improving the generation of protonic acid sites in the isomerization of C6 alkane and cycloalkanes

This paper describes a study of the nature of metal-free protonated fibrous silica BEA (HSi@BEA) and its ability to generate protonic acid sites originating from molecular hydrogen and from C6 alkanes and cycloalkanes. HSi@BEA was successfully synthesized by a microemulsion system and subsequently applied in n-hexane, cyclohexane and methylcyclopentane isomerization. The HSi@BEA consisted of microspheres with a bicontinuous concentric lamellar structure morphology. Its core was mainly composed of an aluminosilicate framework of BEA, while the lamellar structure consisted of silica. The particle size of HSi@BEA was in the range of 400 nm to 700 nm with pore diameters between 3.6 nm to 5.6 nm and 15 nm to 25 nm. 27 Al MAS NMR results showed that the additional silica lamellar structure of the HSi@BEA increased the extra-framework aluminum (AlOH) which acts as Lewis acidic sites in the catalyst. FTIR results revealed that these additional Lewis acid sites in the metal-free catalyst generated a high amount of protonic acid sites by playing a role as electron acceptors after the dissociation of H2 and C6 alkane and cycloalkanes. Significantly, the participation of more protonic acid sites enhanced the catalytic performance of the C6 alkanes and cycloalkanes, n-hexane, cyclohexane and methylcyclopentane, at a low reaction temperature of 423 K. The presence of a silica lamellar structure resulted in a two to threefold higher isomer yield of n-hexane, cyclohexane and methylcyclopentane compared to bare HBEA catalyst which mainly produces cracking products. In addition, a kinetics study showed that the activation energy could be lowered by two to three times at elevated temperatures in the range of 423 K to 623 K.

Platinum and Molybdenum Oxide Supported on Mesostructured Silica Nanoparticles for n-Pentane and Cyclohexane Isomerization

Alkane isomerization into its equivalent branched isomers has gained numerous attention as a reaction to obtain high quality fuel. In this study, platinum and molybdenum oxide supported on mesostructured silica nanoparticles (Pt/MoO3/MSN) was prepared via impregnation method and tested for n-pentane and cyclohexane isomerization. The catalyst was characterized by using X-ray diffraction (XRD), nitrogen (N2) physisorption, and pyridine Fourier-transform infrared (pyridine-FTIR) spectroscopy. The IR result revealed that the addition of Pt and MoO3 into MSN formed different strength of Lewis and Brönsted acid sites. It was observed that the catalyst possessed strong acid sites and several numbers of relatively weak Lewis and Brönsted acid sites. Pt/MoO3/MSN was catalytically active towards n-pentane and cyclohexane isomerization with conversion of 63 and 87%, respectively, at 300 °C. It was proposed that the addition of Pt might assist the generation of active protonic acid sites from molecular hydrogen via the mechanism of hydrogen spillover and hence improve isomerization reaction.

Fe(III)‐Exchanged Montmorillonite as Reusable Heterogeneous Protonic Acid Catalyst for Michael Addition of Indole in Water

AbstractFe3+‐exchanged montmorillonite (Fe3+‐mont) was found to be an effective and a reusable heterogeneous acid catalyst for the Michael addition of indole with methyl vinyl ketone at 333 K in H2O to afford 4‐(1H‐indol‐3‐yl)butan‐2‐one in high yields. Investigations on activity of the Fe3+‐mont catalyst for deprotection of acetal and Meerwein‐Ponndorf‐Verley (MPV) reduction of aldehyde suggest that protonic acid sites of the Fe3+‐mont catalyst are responsible for the present Michael addition of indole.

Effect of Cr2O3 loading on the properties and cracking activity of Pt/Cr2O3-ZrO2

The effects of Cr2O3 loading ranging from 1 to 12wt.% on the properties, structure and isopropylbenzene (IPB), 1,4-diisopropylbenzene (DIPB) and 1,3,5-triisopropylbenzene (TIPB) hydrocracking activities of Pt/Cr2O3-ZrO2 (Pt/CrZr) were studied. The properties of Pt/CrZr were characterized with XRD, BET, IR and UV–vis spectrometer. The acidity was determined by 2,6-lutidine adsorbed IR spectroscopy. The introduction of Cr2O3 on ZrO2 intensified continuously the tetragonal phase of ZrO2 and bulk crystalline Cr2O3, while the surface area and acidity passed through a maximum of Cr2O3 loading at 8wt.%. The IR study confirmed the presence of CrO stretching bands at 1035 and 1013cm−1 on Pt/CrZr. No dioxo species involving the stretching modes of OCrO existed. H2 and 2,6-lutidine showed different interactions with Pt/CrZr in which the band at 1013cm−1 is more extensively affected with 2,6-lutidine adsorption for all Pt/CrZr and the band at 1035cm−1 is more affected with H2 adsorption for Cr2O3 loading at≤8wt.%. While, at >8wt.% Cr2O3 loading, the H2 is more interacted with the band at 1013cm−1. These results suggested that the absorbance bands at 1013 and 1035cm−1 are assignable to the stretching of the CrO which is connected to the other Cr through O and CrO which is connected to cus Zr4+ through O, respectively. The catalyst with 8wt.% loading performed with a maximum activity in IPB, DIPB and TIPB hydrocracking at 523K which may be due to presence of CrO band at 1035cm−1 which extensively interacted with H2 to form protonic acid sites via a hydrogen spillover phenomenon. In fact, Cr2O3 loading at 8wt.% possessed strong permanent Lewis acid sites which play an important role in the stabilization of an electron during the formation of protonic acid sites.

The cooperative effect of Zn on Co/HZSM-5 catalyst for NO reduction with methane

The cooperation of Zn and Co in the Zn-Co/HZSM-5 catalyst was investigated. NO was selectively reduced by CH4 to N2 in the presence of excess O2, and the catalytic activity depended on both the activation of CH4 and the adsorption properties of NOx. It was found that the addition of Zn could effectually heighten the selectivity of methane to NOx. The results of H2-TPR, NH3-TPD and XPS proved that addition of Zn into Co/HZSM-5 could inhibit the formation of bulk Co3O4 on the outer surface of the catalyst. Reducing the bulk Co3O4 would restrain the combustion of methane and improve the selectivity of methane to NOx, which was very consistent with the experimental results. MS-TPD results showed that Zn contributed the form of NO2 and strengthened its adsorption on the Co/HZSM-5 catalyst. So the reaction mechanism is proposed to occur via two successive elementary steps. First NO is oxidized to NO2 on the dispersed CoOx sites or Co2+ active sites; then NO2 is adsorbed on Zn2+ sites, and further reacts with methane on proton acid sites. The key step is the adsorption of NO2. Zn directly participates in the reaction by adsorption of NO2.

EFFECT OF SUPPORT ON MOLYBDENUM OXIDE ACIDITY FOR N-HEPTANE ISOMERIZATION

Skeletal isomerization of alkanes into the corresponding branched isomers has attracted many attentions as a reaction to produce clean fuel with high octane quality. In this study, molybdenum oxide (MoO3) catalyst supported on mesostructured silica nanoparticles (MSN), HZSM-5 and MCM-41 activity were being tested towards n-heptane isomerization at 623 K. The catalyst acidity was characterized by using FTIR pre-adsorb pyridine. The results showed that MoO3-MSN possesses highest Lewis acid and lowest Brönsted acid concentrations. The catalytic testing towards n-heptane isomerization showed that MoO3-MSN exhibited the highest n-heptane conversion of 18.7 % at 623 K. It was suggested that the high Lewis acid in the MoO3-MSN may facilitate the formation of active protonic acid sites from molecular hydrogen through hydrogen spillover mechanism and hence improves the n-heptane conversion.