Amount Of Strong Acid Sites Research Articles

Unprecedented contributions of thinner ferrierite zeolite morphology for superior gas-phase dimethyl ether carbonylation activity

String-like thinner morphology of FER zeolite (SFER) having considerable amount of strong acidic sites was successively synthesized by using two different organic structure directing agents (OSDA) such as CTAB and piperidine, which showed larger number of active strong Brønsted acid sites with higher catalytic activity and stability for a gas-phase carbonylation of dimethyl ether (DME) to methyl acetate (MA). The effects of synthesis procedures and surface properties were verified by using surface acidic sites measurements and molecular dynamics (MD) analysis, where an appropriate molar ratio of CTAB to piperidine (∼0.5) showed the most stable DME adsorption natures with catalytic stability. The ultrathin-layers with string-like FER morphology were found to be excellent to enhance a gas-phase DME carbonylation activity with an increased stability of the FER structures, which was mainly attributed to the enhanced mass transfer rate in the string-like thinner FER micro and mesopore channels with larger strong Brønsted acid sites resulted in the suppressed depositions of coke precursors.

High-yield synthesis of alkyl levulinate from furfuryl alcohol and its upgrading to 2-methyl-1,3-dioxolane over AgPW

In order to relieve greenhouse effect, it is highly urgent to convert carbon-neutral biomass to value-added chemicals and liquid fuels by designing new process. 96.5% yield of biofuel alkyl levulinate was achieved in the alcoholysis of furfuryl alcohol with ethanol over highly active Ag+ exchanged H3PW12O40 (AgPW) catalyst at low temperature. In situ XRD, 31P MAS NMR, XPS and NH3-TPD results confirm that AgPW contains large amounts of strong acid sites and stable Keggin structure, resulting in the excellent performance. Subsequently, new process was developed to synthesize biofuel 2-methyl-1,3-dioxolanes (MDL) with ∼70% yields via a tandem furfuryl alcohol alcoholysis and acetalization reaction over AgPW. Additionally, MDL can be availably obtained from furfural, xylose and hemicellulose by an integrated multi-step process.

Effects of parameters in the preparation of Mo/MWW-type catalysts on the dehydroaromatization of shale gas

The direct non-oxidative aromatization of shale gas offers an unconventional production route for BTX (benzene, toluene, and xylene), potentially alleviating the heavy dependence of BTX supply on petroleum-based processes. Zeolite-supported transition metal catalysts have been successfully applied in the aromatization of light alkanes, where the zeolites provide the appropriate shape selectivity and acidity that are beneficial for the production of aromatics. In addition to HZSM-5, MCM-22 has also been recognized to be an effective support, owing to the characteristic topology of MWW structure. Here, we present a systematic investigation into the preparation and optimization of Mo/MWW-type catalysts, aiming to maximize their performance in shale gas aromatization. Mo/MCM-22 exhibited a superior initial BTX yield compared to Mo/ZSM-5 with a comparable Si/Al ratio, but was rapidly deactivated. A moderate value of Si/Al (∼ 11) was required for optimal catalytic performance, as an excessive amount of Al during the synthesis of MCM-22 led to insufficient amount of strong acid sites that are favorable for the reaction. The inclusion of Ga in MCM-22 greatly deteriorated the aromatization activity, owing to a significant degree of degalliation under reaction conditions. Contrary to ZSM-5, pelletization of MCM-22 also had a noticeable impact on catalytic performance, which was attributed to the nature of MWW topology. These results provide a comprehensive understanding of designing MWW-type zeolites for their application in shale gas aromatization.

Excellent operating temperature window and H2O/SO2 resistances of Fe-Ce catalyst modified by different sulfation strategies for NH3-SCR reaction.

Expecting to gain an excellent operating temperature window and superior catalytic activity of the catalyst in SCR reaction, the Fe-Ce bimetallic oxide catalyst was firstly prepared and sulfated with two different sulfation strategies by H2SO4. It is interestingly found that both the two sulfation strategies can significantly broaden the operating temperature window of the catalyst. In particular, the SFC and FCS both exhibit superior resistance to H2O + SO2, and the NOx conversion of the SFC even displays no changes in the coexistence of H2O and SO2. The characterization results show that different sulfation strategies can generate amorphous sulfate species rather than bulk sulfate species. Furthermore, more surface-adsorbed oxygen as well as higher contents of Ce3+ and Fe3+ can be obtained on the sulfated catalysts, especially for the SFC catalyst. Meanwhile, different sulfation strategies will progressively enhance the redox ability and amounts of strong acid sites, which will contribute to broadening the operating temperature window for the NH3-SCR reaction. Additionally, different sulfation methods do not change the reaction pathway of catalysts. However, the adsorption of ad-NH3 species and reactivity of ad-NOx species are significantly changed. These lead to the reaction pathway shifts to E-R direct over the SFC and the promotion of E-R and L-H mechanisms over the FCS catalyst.

Synergistic roles of surface acidity and Ni species in NiF2/AlF3 catalysts for pyrolysis of 1,1,1,2-tetrafluoroethane

A series of NiF2/AlF3 catalysts were prepared and tested for pyrolysis of 1,1,1,2-tetrafluoroethane. The effects of nickel precursors and reduction pretreatment on the catalytic performance were investigated. Compared to the NiAlF-N (with nitrate as the precursor) and NiAlF-A (with acetate as the precursor) catalysts, the NiAlF-C catalyst (with chloride as the precursor) with the lowest strong acidity gave the lowest initial reactivity (r0 = 158.7 μmol g−1 min−1 at 500°C) but the best stability. The surface Lewis acid sites are the crucial active sites for C-F bond break, but excessive strong acid sites result in serious carbon deposition on the catalysts and thus drastic deactivation. Besides, the Ni0 species are new active sites for C-H activation, which accounts for the higher activity of the pre-reduced catalyst (denoted as NiAlF(H)) than that of the NiAlF. The NiAlF(H)-C catalyst gave a conversion of 29.2% and a high selectivity of 99% at 500 °C, also remained stable for 10 h. Its good performance was attributed to combined roles of surface Ni0 species and low amount of strong acid sites.

Thiophene-functional hierarchical carbons for the removal of ionic and organic mercury in light hydrocarbon liquids: Synthesis, evaluation and adsorption mechanism

A simple synthesis of thiophene-functional zeolite-templated carbons (ZTCs) is proposed to remove ionic mercury (Hg2+) and organic mercury (Hgorg) from gasoline. Microporous zeolite (Beta) and mesoporous zeolite (MCM-41) were used to prepare porous carbon by impregnating with 2-thiophenemethanol (ThM) to explore the influence of template type on the quality of templated carbon. The amount of strong acidic sites in MCM-41 zeolite was more than Beta zeolite which promoted the catalytic polymerisation of the ThM in the pores structure of the zeolite and highly templated carbon was obtained. The impregnation concentration of ThM on the structure and functional groups of the samples was explored. It was found that increasing the concentration of ThM properly can promote the filling of zeolite pores by ThM and form more ordered templated carbons. In addition, the increased ThM promoted the formation of the S = O and C-O oxygen-containing functional groups. The optimal impregnation concentrations of ThM were 25% for B-Al (25%-B-Al-ZTC) and 75% for M−Al (75%-M−Al−ZTC). The 75%-M−Al−ZTC with sufficient S = O and C-O oxygen-containing functional groups showed excellent mercury adsorption capacity (617.49 μg/g) and a high intra-particle diffusion rate (294.10 h−1). The simultaneous adsorption of Hg2+ and Hgorg was also conducted and it was found that Hgorg had competitive adsorption for Hg2+ which led the total adsorption capacity to decrease. In addition, the 25%-B-Al-ZTC and 75%-M−Al−ZTC adsorbents had good regeneration ability and the adsorption capacity remained over 75% and 71% for Hg2+ and Hgorg after five desorption-sorption cycles, respectively. Thus, the new adsorbents with stable and efficient Hg removal performance have the potential for practical application by oil refineries.

Manganese oxide nanorod catalysts for low-temperature selective catalytic reduction of NO with NH3.

MnOx nanorod catalysts were successfully synthesized by two different preparation methods using porous SiO2 nanorods as the template and investigated for the low-temperature selective catalytic reduction (SCR) of NO with NH3. The catalysts were characterized by scanning electron microscopy, transmission electron microscopy, nitrogen adsorption, X-ray diffraction, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption. The results show that the obtained MnOx-P nanorod catalyst prepared by redox precipitation method exhibits higher NO removal activity than that prepared by the solvent evaporation method in the low temperature range of 100–180 °C, where about 98% NO conversion is achieved over MnOx(0.36)-P nanorods. The reason is mainly attributed to MnOx(0.36)-P nanorods possessing unique flower-like morphology and mesoporous structures with high pore volume, which facilitates the exposure of more active sites of MnOx and the adsorption of reactant gas molecules. Furthermore, there is a lower crystallinity of MnOx, higher percentage of Mn4+ species and a large amount of strong acid sites on the surface. These factors contribute to the excellent low-temperature SCR activity of MnOx(0.36)-P nanorods.

The Effect of Catalyst Calcination Temperature on Catalytic Decomposition of HFC-134a over γ-Al2O3

This paper explores the thermal and catalytic pyrolysis of HFC-134a over γ-Al2O3 calcined at temperatures of 550 °C (A550), 650 °C (A650), 750 °C (A750), and 850 °C (A850). The physicochemical properties of catalysts were studied through thermogravimetric analysis (TGA), Brunauer–Emmett–Teller equation for nitrogen physisorption analysis (BET), X-ray diffraction (XRD), and temperature-programmed desorption of ammonia (NH3-TPD). The non-catalytic pyrolysis of HFC-134a showed less than 15% decomposition of HFC-134a. Catalysts increased the decomposition as A650 revealed the highest decomposition efficiency by decomposing more than 95% HFC-134a for 8 h followed by A750, A850, and A550. The larger surface area and pore volume paired with a low amount of strong acidic sites were considered as the main contributors to the comparatively longer catalytic activity of A650.

Development of a New Ternary Al2O3-HAP-Pd Catalyst for Diethyl Ether and Ethylene Production Using the Preferential Dehydration of Ethanol.

This study aims to convert ethanol to higher value-added products, particularly diethyl ether and ethylene using the catalytic dehydration of ethanol. Hence, the gas-phase dehydration of ethanol over Al2O3-HAP catalysts as such and modified by addition of palladium (Pd) in a microreactor was evaluated. The commercial Al2O3–HAP catalyst was first prepared by the physical mixing method, and then, the optimal ratio of the Al2O3–HAP catalyst (2:8 by wt %) was impregnated with Pd to develop a new functional catalyst to alter surface acidity. Based on the results, the combination of Al2O3 and HAP catalysts generated significant quantities of weak acid sites which demonstrates an enhancement in catalytic activity. In addition, Pd modification in the optimal composition ratio of the Al2O3–HAP catalyst extremely increased the amount of weak acid sites as well as weak acid density due to the synergistic effect between the Pd and Al2O3–HAP catalyst that are supposed to suggest the active sites in the reaction. Among all catalysts, the Al20-HAP80-Pd catalyst displayed brilliant catalytic performance in the course of diethyl ether yield (ca. 51.0%) at a reaction temperature of 350 °C and ethylene yield (ca. 75.0%) at a reaction temperature of 400 °C having an outstanding stability under time-on-stream for 10 h. This is recognized to the combination of the effects of weak acid sites (Lewis acidity), small amount of strong acid sites, and structural characteristics of the catalytic materials used.

Tuning hierarchical ZSM-5 for green jet fuel production from soybean oil via control of Pt location and grafted TPABr content

Hierarchical ZSM-5 was prepared using tetrapropylammonium bromide (TPABr) grafted multiwalled carbon nanotubes loaded with Pt as a bifunctional template for hydroconversion of soybean oil to obtain bio-jet fuel. With the increase in the grafted-TPABr-Pt loading, the deoxygenation reaction enhanced and the amount of strong acid sites and Brønsted to Lewis acid site ratio significantly increased, leading to an increase in the C4–C8 and C9–C15 fractions. Moreover, the presence of Pt in the mesoporous channels inhibited the hydrocracking reaction and enabled suitable selectivities for the C9–C15 and aromatics, in contrast to the Pt in the micropores and on the surface.

Supercritical catalytic cracking of n-dodecane over air-oxidized activated charcoal

The direct conversion of n-dodecane to light alkenes with an efficient catalyst can enhance the combustion efficiency and cooling performance of endothermic heat sinks for the development of propellants suitable for supersonic vehicles. In this work, a pretreated activated charcoal showed excellent performance as a novel cracking catalyst superior to the conventional ZSM-5 zeolite catalyst. Activated charcoal was oxidized at 298, 473, and 673 K, leading to surface modification, and n-dodecane cracking experiments were carried out at 4 MPa and 723 K. The activated charcoal exhibited a higher light alkene selectivity and heat sink capacity compared with the conventional ZSM-5. The charcoal oxidized at 673 K showed the highest light alkene selectivity of 28% among the tested catalysts, exceeding that of the reference ZSM-5 by 18%. The oxidizing pretreatment of the charcoal at high temperatures was found to generate carboxylic functional groups acting as Brӧnsted acid sites based on characterization by X-ray photoelectron spectroscopy, FT-IR, and temperature-programmed desorption with NH3. The activated charcoal oxidized at 673 K had the largest amount of strong acid sites and Brӧnsted acid sites, which led to the highest conversion of n-dodecane and the selectivity of light alkene.

Modification of MWW Layer Structure to investigate the Effect of Acidity and Zn-type sites on Ethane Dehydroaromatization

MWW derivatives zeolite of MCM-22 with 3D layer structure, MCM-56 with partial disordered layer, MCM-36 with pillared layer and ITQ-2 with delaminated layer were prepared by hydrothermal synthesis and further modification to investigate the effect of acidic and interlayer structure on the catalytic performance of ethane dehydroaromatization and ethylene aromatization. With the retention of the MWW structure and confirmation of the intercalation or delamination efficiency, it was found that the increased exposed half-cup pocket and aluminum site on the external MWW layer structure can improve the xylene selectivity and catalytic stability. Although the amounts of total and strong acid site of H-form ITQ-2, MCM-36, MCM-56 are lower than those of MCM-22, the ratio of Lewis(L)/Brönsted(B) acid sites increases, which indicates that the exposed tri-coordinated framework aluminum in the half-cup pocket of external surface generated by exfoliation and pillaring can acted as the L acid sites. After loading Zn species, the strong acid amount and L acid sites amount are improved by the interaction between the loaded Zn species and MWW framework aluminum. The impregnated Zn species exist on the MWW zeolite with the state of ZnO and ZnAl2O4. The Zn species play roles of both ethane dehydrogenation and ethylene aromatization. The strong B acid sites play an important role for the oligomerization and aromatization of light olefins, while the excess amount of strong acid sites causes the increasing of cracking step which favors for light olefins production.

High dispersed Ru/SiO2-ZrO2 catalyst prepared by polyol reduction method and its catalytic applications in the hydrodeoxygenation of phenolic compounds and pyrolysis lignin-oil

Metal particle size and metal dispersion significantly influence the catalyst activity, and an efficient catalytic upgrade of bio-oil to high-quality liquid fuel is always difficult. Herein, a high dispersed Ru/SiO2-ZrO2 catalyst was prepared by polyol reduction method, which exhibited a high catalytic activity on hydrodeoxygenation (HDO) of the phenolic compounds and pyrolysis lignin-oil. As a model compound, guaiacol had a conversion of 99.9% and a cyclohexane selectivity of 96.7% at the temperature of 240 °C. This polyol Ru/SiO2-ZrO2 catalyst had a good recyclability in the guaiacol HDO. No significant decrease on the catalytic activity was presented after continuous 5 runs, and the conversion kept close to 100% and the selectivity of cyclohexane kept above 88%. Several common phenolic compounds also enabled to be turned into corresponding cycloalkanes efficiently. The high Ru dispersion and the large amount of strong acid sites in the polyol Ru/SiO2-ZrO2 are the main reasons for the good catalytic performances. The synergetic effects between high dispersed metal site and strong acid site lead to a promoted efficiency in the HDO process to form the cycloalkanes. This active catalyst was also applicable to the upgrade of pyrolysis lignin-oil. After reaction, the content of hydrocarbons in the lignin-oil increased from 16.2% to 86.1%, and guaiacols and other oxygenated compounds were almost disappeared. The upgraded lignin-oil has potential to be used as high-quality fuels directly.

Synthesis, Modification, and Characterization of CuO/ZnO/ZrO2 Mixed Metal Oxide Catalysts for CO2/H2 Conversion

CuO/ZnO/ZrO2 catalyst systems were synthesized in different ways and comprehensively characterized in order to study synthesis-to-property relations. A series of catalyst samples was prepared by coprecipitation, one-pot synthesis, and wet impregnation. The coprecipitation of multicomponent precipitates is usually a preliminary stage for preparation of mixed oxide catalysts. Cetyltrimethylammonium bromide (CTAB) was used in the surfactant-supported coprecipitation to improve the structural or textural characteristics of the catalytic samples. In the one-pot synthesis, all necessary components are simultaneously converted by evaporation from solutions into solids. During the wet impregnation, zirconium hydroxide is loaded with metal salts. After thermal treatment, all samples formed pure metal oxide forms, which was confirmed by XRD. The specific surface area of the investigated samples and their porous texture were determined by nitrogen adsorption. The reducibility of metal oxides and the kind of CuO phase was characterized by temperature-programmed reduction (TPR), and the surface acid properties by temperature-programmed ammonia desorption (TPAD). The CuO/ZnO/ZrO2 sample with the highest amount of strong acid sites is characterized by the formation of large CuO particles combined with the worst reducibility so that potentially catalytic active Cu/CuO pairs can be formed. One catalyst system was further characterized by in situ diffuse reflection Fourier transform infrared spectroscopy (DRIFTS) to identify surface intermediate species, which may occur during the conversion of CO2/H2 to methanol.

Effect of framework Al siting on catalytic performance in methanol to aromatics over ZSM-5 zeolites

ZSM-5 zeolites with different framework Al (AlF) siting were hydrothermally synthesized by adding mineralizer, urea, or by changing the silicon source. The morphology, textural properties, AlF siting, and acidity of different ZSM-5 zeolites were characterized using SEM, XRD, BET, XRF, MAS NMR, NH3-TPD, and Py-FTIR. Furthermore, methanol to aromatics (MTA) was used to investigate the catalytic performance of different catalysts. The results suggested that different ZSM-5 zeolites were highly crystalline with a uniform morphology, but there were large differences in AlF siting and acidity. The AlF in the ellipsoidal ZSM-5 sample was mainly distributed in straight or sinusoidal channels and displayed more acidic sites. AlF of bulk ZSM-5 was mainly located at the intersection of channels, and it showed the lowest amount of strong acid sites. The ellipsoidal ZSM-5 catalyst in which AlF was mainly located in straight or sinusoidal channels exhibited more acidic sites and higher stability and aromatic selectivity during the MTA reaction.

Free-H2 deoxygenation of Jatropha curcas oil into cleaner diesel-grade biofuel over coconut residue-derived activated carbon catalyst

Diesel-like hydrocarbons were produced by the catalytic deoxygenation (DO) of Jatropha curcas oil (JCO) over novel Agx/AC and Niy-Agx/AC catalysts under an H2-free atmosphere. The AC was synthesized from coconut fibre residues (CFR), where CFR is the by-product from coconut milk extraction and is particularly rich in soft fibres with high mineral content. The Niy-Agx/AC catalyst afforded higher DO activity via the decarboxylation/decarbonylation (deCOx) route than Agx/AC due to the properties of Ni, synergistic interaction of Ni and Ag species, adequate amount of strong acid sites and large number of weak acid sites, which cause extensive C-O cleavage and lead to rich formation of n-(C15+C17) hydrocarbons. The effect of Ag and Ni content were studied within the 5 to 15 wt% range. An optimum Ni and Ag metal content (5 wt%) for deCOx reaction was observed. Excess Ni is not preferable due to a tendency for cracking and Ag-rich containing catalyst weakly enforced triglycerides breaking. The Ni5-Ag5/AC govern exclusively decarbonylation reaction, which corroborates the presence of Ni2+ species and a high amount of strong acid sites. Ultimately, Ni5-Ag5/AC in the present study shows excellent chemical stability with consistent five reusability without drastic reduction of hydrocarbon yield (78–95%) and n-(C15+C17) selectivity (82–83%), which indicate favourable application in JCO DO.

Prins cyclisation of (–)-isopulegol with benzaldehyde over ZSM-5 based micro-mesoporous catalysts for production of pharmaceuticals

Several ZSM-5 derived micro-mesoporous catalysts were investigated in Prins cyclisation of (–)-isopulegol with benzaldehyde acting as a reactant and a solvent for production of heterocyclic oxygen containing 2H-chromene derivatives including the tetrahydropyran structure and exhibiting biological activity. The investigated catalysts were characterized by nitrogen adsorption, ammonia temperature programmed desorption, adsorption-desorption of pyridine and 2,6-di-tert- butylpyridine with Fourier transform infrared spectroscopic control. For the Prins reaction performed at 70 °C, the highest yield of the desired product, equal to 67% at complete conversion of (–)-isopulegol, was obtained over a micro-mesoporous catalyst containing an optimum amount of strong acid sites and mesopores, being 12 fold larger than the size of the desired product.

Recycling benzene and ethylbenzene from in-situ catalytic fast pyrolysis of plastic wastes

Recovering waste plastics by catalytic fast pyrolysis to selectively generate aromatic hydrocarbons is a promising approach to dispose of solid wastes. In the present work, catalytic conversion of polystyrene over ultra-stable Y zeolites (USY) was conducted to directionally produce benzene and ethylbenzene. Experimental results indicated that catalyst type considerably affected the distribution of aromatic hydrocarbons, and USY with high surface area (734 m2/g), large pore size (5.6 nm), and an abundant amount of strong acid sites (1.21 mmol/g) exhibited the most effective shape selectivity for ethylbenzene and benzene generation as the yield enhanced rate reached 401.8% and 61.1%, respectively. Plastic type also played a vital role in the formation of desirable aromatic hydrocarbons, and polystyrene was more beneficial to the production of ethylbenzene as a 54-fold increase was obtained compared to polycarbonate in the catalytic degradation process. Concerning reaction conditions to maximize the formation of benzene and ethylbenzene in the catalytic decomposition of polystyrene, the catalyst/feedstock mass ratio, Si/Al mole ratio in USY, and catalytic conversion temperature could be optimized at 1.5, 5.3, and 650 °C, respectively.

Catalytic performance of NiMo/Al2O3-USY in the hydrocracking of low-temperature coal tar

A series of NiMo/Al2O3-USY catalysts with different MoO3 contents were prepared through incipient wetness method and further modified with NH4F. The NiMo/Al2O3-USY catalysts were characterized by XRD, XPS, HR-TEM, NH3-TPD, H2-TPR and N2 adsorption and their catalytic performance in the hydrocracking of low-temperature coal tar (LTCT) was investigated in a 200 mL fixed-bed reactor. The results indicate that the appropriate MoO3 content is 15%; higher MoO3 content may lead to the agglomeration of active metals on the support, although it has little influence on the sulfidation degree of Mo species and the conversion of coal tar upon hydrocracking. In addition, the amount of strong acid sites and pore diameter decrease gradually with a further increase in the MoO3 content, which is disadvantageous for deep hydrocracking. The modification of USY zeolite with NH4F solution can enlarge the average pore diameter of resultant NiMo/Al2O3-USY catalysts and then improve the residue conversion of coal tar. However, the amount of strong acid sites decreases obviously when the concentration of NH4F solution exceeds 0.6 mol/L, which may lead to an increase of the sulfur content in the hydrocracking product. Over the NiMo/Al2O3-USY catalyst modified with 0.6 mol/L NH4F solution, the residue conversion of coal tar reaches 87.65%; the sulfur contents in the gasoline fraction (< 180°C) and diesel fraction (180–320°C) are 5.96 and 34.98 mg/kg, respectively.

The negative effect of P addition of La/HZSM-5 on the catalytic performance in methyl mercaptan abatement

The effect of P addition on the catalytic performance of La/HZSM-5 in methyl mercaptan abatement was investigated in the present work. It was shown that the addition of phosphorus could decrease the amounts of strong acid sites over the P-doped 13%La/HZSM-5 samples, but expected coke resistance ability was not obtained. To our surprise, P-doped 13%La/HZSM-5 samples exhibited decreased activity and stability for methyl mercaptan abatement. Moreover, the 13%La/HZSM-5 supported P catalysts were prepared and characterized by NH3-TPD, FT-IR, XRD and XPS, and it was found that the introduction of P species into La/HZSM-5 catalyst provokes a reaction with La2O3 and La2Ox(CO3)y species, which were reported to be active sites for methyl mercaptan conversion. As a result, P addition generated some inactive species such as AlPO4, Al(PO3)3, LaPO4 and La(PO3)3 species, causing the deactivation of the catalyst. These results conversely proved the necessary presence of active La2O3 and La2Ox(CO3)y species in the La/HZSM-5 catalyst for eliminating CH3SH.