NH3 Temperature-programmed Desorption Research Articles

Elucidating the Role of CO2 in the Soft Oxidative Dehydrogenation of Propane over Ceria-Based Catalysts

A mixed oxide support containing Ce, Zr, and Al was synthesized using a physical grinding method and applied in the oxidative dehydrogenation of propane using CO2 as the oxidant. The activity of the support was compared with that of fully formulated catalysts containing palladium. The Pd/CeZrAlOx material exhibited long-term stability and selectivity to propene (during continuous operation for 140 h), which is not normally associated with dehydrogenation catalysts. From temperature-programmed desorption of NH3 and CO2 it was found that the catalyst possessed both acidic and basic sites. In addition, temperature-programmed reduction showed that palladium promoted both the reduction and reoxidation of the support. When the role of CO2 was investigated in the absence of gas-phase oxidant, using a temporal analysis of products (TAP) reactor, it was found that CO2 dissociates over the reduced catalyst, leading to formation of CO and selective oxygen species. It is proposed that CO2 has the dual role of regener...

Synthesis, characterization and hydroisomerization activity of ZSM-22/23 intergrowth zeolite

ZSM-22/23 intergrowth zeolite was synthesized by hydrothermal method using N,N-dimethylformamide (DMF) and 1, 6-diaminohexane (DAH) as structure directing agents (SDAs). Interestingly, addition of ZSM-22 directing SDA in the range of 2.5–7.5 mol% in the gel of ZSM-23 has been found to have dominant templating effect and favored formation of intergrowth (ZSM-22/23) structure and is found to influence crystallization of intergrowth phase with 60% ZSM-22 (TON) character. The physicochemical properties of ZSM-22/23 intergrowth phase were characterized by X-ray diffraction (XRD), N2-physisorption, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), NH3-Temperature Programmed Desorption (NH3-TPD), and Nuclear Magnetic Resonance Spectroscopy (CPMAS NMR), respectively. The characterization result suggests the formation of intergrowth zeolite having needle shaped morphology and Si/Al ratio in the range of 60–120 with moderate acidity in the range of 50–120 μmol/g, and desired textural properties (surface area ∼200 m2/g and pore volume ∼ 0.15 cc/g). The performance of intergrowth for hydroisomerization of n-hexadecane was evaluated by preparing catalysts in extrudate form by supporting ∼0.32% Platinum (Pt) on catalyst body containing zeolite and alumina (50:50 wt%). The platinum content in Pt-ZSM-22/23 was determined by Inductively Coupled Plasma (ICP), The catalyst based on intergrowth phase bulk Si/Al ratio of 60 showed maximum isomer selectivity of 89% with ∼80% yield at 90% conversion was observed at 303 °C.

Tert-Butylation of Toluene with Tert-butanol Over Transition Metal Oxide-Modified Hbea Zeolite

A series of transition metal oxide-modified HBEA (M x0 y/HBEA) zeolite catalysts were prepared by the wetness impregnation method, and investigated for the alkylation of toluene with tert-butanol to synthesise 4- tert-butyltoluene (4-TBT). Their physico-chemical properties were characterised by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller and NH3 temperature-programmed desorption methods. M x0 y/HBEA zeolite showed higher para-selectivity than parent HBEA due to its improved structural and acidic properties. Though the toluene conversion of M x0 y/HBEA catalyst decreased, the 4-TBT selectivity increased significantly at 190 °C after 4 h. The narrowed pores after loading the M x0 y prompted an increase in selectivity for 4-TBT by increasing the shape selectivity. In addition, the decrease in strong acid sites increased selectivity for 4-TBT by suppressing further isomerisation of the 4-TBT formed on acid sites. Among all the modified HBEA zeolites, Fe203/HBEA exhibited the best catalytic activity and para-selectivity. The factors affecting the reaction over Fe203/HBEA have also been investigated extensively.

Hydrogenolysis of glycerol to 1,3-propanediol over Li2B4O7-modified tungsten–zirconium composite oxides supported platinum catalyst

A series of Pt–yLi2B4O7/WOx/ZrO2 (y = 0, 0.5, 1, 2 wt%) catalysts were prepared by varying the content of Li2B4O7 through the method of coimpregnation-calcination. The obtained catalysts were used for the selective hydrogenolysis of glycerol to 1,3-propanediol. Meanwhile, these catalysts were characterized by N2 adsorption and desorption (BET), CO chemisorption, X-ray diffraction (XRD), NH3-temperature programmed desorption (NH3-TPD), H2-temperature programmed reduction (H2-TPR), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The results showed that Pt–1Li2B4O7/WOx/ZrO2 achieved the highest activity with glycerol conversion of 90.7% at 150 °C and 4 MPa and exhibited excellent stability over 200 h. Pt/WOx/ZrO2 catalyst modified with Li2B4O7 was able to enhance catalytic activity and stability, since Li2B4O7 promoted the dispersion of Pt, increased the acid amount of the catalyst and strengthened the interaction between active components and support.

Zirconium-modified mesoporous silica as an efficient catalyst for the production of fuel additives from glycerol

Zirconium-modified mesoporous silica (ZrS) was synthesized as a new promising catalyst for the acetylation reaction of glycerol. In the presence of ZrS catalyst, the selectivity to desired products (TAG and DAG) reached 91%, with a complete conversion of glycerol. Moreover, 12-tungstophosphoric acid (H3PW12O40) was immobilized onto ZrS surface, and the effect of acid strength of catalysts on this reaction was investigated by NH3-temperature programmed desorption (NH3-TPD) technique. Synthesized materials were characterized by various analytical techniques: X-ray powder diffraction, scanning electron microscopy, N2 adsorption–desorption, and inductively coupled plasma spectroscopy.

Synthesis of highly selective and stable mesoporous Ni–Ce/SAPO-34 nanocatalyst for methanol-to-olefin reaction: Role of polar aprotic N,N-dimethylformamide solvent

A series of mesoporous nanocrystalline silicoaluminophosphate (SAPO) zeolites (SAPO-34) were synthesized via an ultrasonic and microwave-assisted hydrothermal method in the presence of [3-(trimethoxysilyl)propyl]octadecyldimethylammonium chloride and cetyltrimethylammonium bromide surfactants as soft templates. Nickel and cerium were then doped on SAPO-34 using incorporation and impregnation methods, and all the catalysts were applied to the methanol-to-olefin (MTO) reaction. The catalysts were characterized using X-ray diffraction, field-emission scanning electron microcopy, inductively coupled plasma–atomic emission spectroscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller analysis, NH3 temperature-programmed desorption analysis, and thermogravimetric analysis. For the impregnation method, the effect of using protic or aprotic solvents as impregnation media on the physico-chemical properties of the metal-based SAPO-34 was investigated. Water and N,N-dimethylformamide (DMF) were employed as the protic and aprotic solvents, respectively. The catalyst prepared using the aprotic DMF solvent exhibited higher dispersion and lower aggregation of metal species compared with that prepared using the protic water solvent. Furthermore, the sample synthesized using the incorporation method exhibited good catalytic performance; however, the Ni–Ce/SAPO-34 sample prepared using the impregnation method and aprotic DMF solvent exhibited superior catalytic performance in the MTO reaction.

Effect of iron doping on SO2 and H2O resistance of honeycomb cordierite-based Mn–Ce/Al2O3 catalyst for NO removal at low temperature

Honeycomb cordierite-based Mn–Ce/Al2O3 (Mn–Ce/Al2O3–C) and Fe–Mn–Ce/Al2O3 (Fe–Mn–Ce/Al2O3–C) catalysts were prepared by an impregnation method and investigated in low-temperature selective catalytic reduction (SCR) of NO with NH3 at 100 °C. The Fe–Mn–Ce/Al2O3–C catalyst exhibited not only higher catalytic activity, but also much better SO2 and H2O resistance in the presence of 30 ppm SO2 and/or 5 vol% H2O than Mn–Ce/Al2O3–C. After doping Fe, the NO conversion of Mn–Ce/Al2O3–C catalyst displayed an increasing trend from 79 to 84% in the absence of SO2 and H2O at 100 °C under a gas hour space velocity of 1667 h−1. The results of characterization indicated that addition of Fe was advantageous to increase BET surface area, pore volume and inhibit loss of surface Mn and Ce species. Additionally, it was helpful for generating higher concentration of Mn4+, more chemisorbed oxygen and more uniform dispersion of amorphous Mn and Ce in the surface of catalyst, which were beneficial to interact with reactants. Furthermore, in contrast to Mn–Ce/Al2O3–C, the SCR activity of Fe–Mn–Ce/Al2O3–C catalyst in the presence of H2O, SO2 and H2O and SO2 were 79, 75 and 64%, with the increase of 14, 18 and 19%, respectively. It is indicated that the addition of Fe could inhibit sulfate formation and thus enhance SO2 resistance. XPS results reveal that the doping of Fe into the ceria lattice led to some Ce4+ transferred into Ce3+ in order to maintain the electrical neutrality, thereby facilitating the reduction of Ce4+ → Ce3+ and the formation of oxygen vacancies. NH3 temperature-programmed desorption (TPD) results imply that the doping of Fe onto Mn–Ce/Al2O3–C can remarkably improve the distribution and concentration of acid sites. All the above factors contributed to the improvement of overall NH3 SCR performance of the Fe–Mn–Ce/Al2O3–C catalyst compared with that of the Mn–Ce/Al2O3–C catalyst.

Nature of Cu Active Centers in Cu-SSZ-13 and Their Responses to SO2 Exposure

The effect(s) of SO2 on the two types of active sites on Cu-SSZ-13 NH3–SCR catalysts, Z2Cu and ZCuOH, were investigated. Two Cu-SSZ-13 catalysts with Si:Al ratios of 6 and 30 were synthesized, and they provide very different distributions of these two active sites. Inductively coupled plasma optical emission spectroscopy (ICP-OES), H2 temperature-programmed reduction (H2-TPR), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were utilized to characterize catalyst samples and quantify the amounts of total Cu, Z2Cu and ZCuOH. In situ DRIFTS results show that Z2Cu and ZCuOH responses to low-temperature (<200 °C) SO2 poisoning were site-dependent. Results of SO2 and SO2 + NH3 temperature-programmed desorption (TPD) and DRIFTS experiments, supplemented with DFT calculations, revealed that the different observed responses correspond to different sulfur intermediates that form. On Z2Cu sites, SO2 only adsorbs when it is cofed with NH3 via formation of ammonium sulfate, with its fingerprin...

The influence of calcination temperatures on the acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol/acetaldehyde mixture

The influences of the calcination temperature on the catalysts’ acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol are investigated. The results show that the 2 wt% ZrO2/Nano-SiO2 calcined at 773 K shows the best performance with the selectivity of 93.18% and conversion of 58.52% when reacted at 593 K, a WHSV of 1.8 h−1 and 3.5:1 volume ratio ethanol-to-acetaldehyde in an atmosphericfixed-bedreactor. Prepared catalysts were characterized by N2 adsorption-desorption, XRD, temperature-programmed desorption of NH3 and CO2, FTIR spectroscopy of adsorbed pyridine and CO2. Based on the relationship between the catalyst activity and its properties, the fact can be presumed that the formation and strength of ZrOSi bond determines the acid-based properties of the catalyst. In addition, moderate-intensity weak acid-basic sites are more suitable for ethanol conversion to BD with the amount of acid and basic sites as close as possible.

Biomass-Derived N-doped Carbon Materials with Silica-Supported Ultrasmall ZnO Nanoparticles: Robust Catalysts for the Green Synthesis of Benzimidazoles.

Ultrasmall ZnO nanoparticles anchored on N-doped carbon materials with a silica support (ZnO/SiO2 -NC) were fabricated from chitosan and metal ions by using a one-pot self-assembly strategy and were successfully applied to the synthesis of 2-arylbenzimidazoles under mild conditions. These catalysts showed excellent stability and could be used six times without any loss of conversion and selectivity. The use of silica gel and the biomass chitosan as a source of hydrophilic N-doped carbon materials facilitated the uniform dispersion of the ZnO nanoparticles in methanol and therefore the contact of these nanoparticles with reactants, thus contributing to a high catalytic performance. TEM analysis showed that the ZnO nanoparticles were around 2.55 nm in diameter and uniformly distributed on the support surface. The binding behavior of ZnO and N-doped carbon materials affected the catalytic activity. Interestingly, temperature-programmed NH3 desorption indicated that the interactions between ZnO and N-doped carbon materials might induce the presence of more acidic sites in these catalysts, thus resulting in enhanced activity and hence promoting this transformation.

The deactivation of a ZnO doped ZrO2-SiO2 catalyst in the conversion of ethanol/acetaldehyde to 1,3-butadiene.

A deactivation study on the ethanol/acetaldehyde conversion to 1,3-butadiene over a ZnO promoted ZrO2–SiO2 catalyst prepared by a sol–gel method was performed. The samples were characterized by N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), NH3 temperature programmed desorption (NH3-TPD), X-ray powder diffraction characterization (XRD), thermogravimetric analyses (TGA), Fourier transform infrared resonance (FT-IR), 13C magic-angle spinning nuclear magnetic resonance (13C NMR) and X-ray photoelectron spectroscopy (XPS). The pore structure characteristics and surface acidity of Zn0.5–Zr–Si catalysts were largely decreased with time-on-stream and no crystal structure was formed in the used catalyst, indicating that the deactivation was caused by carbon deposition. Two main types of carbon deposition were formed, namely low-temperature carbon deposition with the oxidation temperature of around 400 °C and high-temperature carbon deposition with the oxidation temperature of 526 °C. The carbon species were mainly composed of graphitized carbon, amorphous carbon, carbon in C–O bonds and carbonyls. The deactivated catalyst could be regenerated by a simple oxidation process in air. Adding a certain amount of water into the feed had a positive effect on reducing the carbon deposition.

Synthesis, characterization and n-hexane hydroisomerization performances of Pt supported on alkali treated ZSM-22 and ZSM-48.

ZSM-48 and ZSM-22 zeolites with similar Si/Al molar ratio have been treated with alkali to modify the pore structures and acidity, and alkali treated ZSM-22 and ZSM-48 samples have been characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), N2 adsorption/desorption, Nuclear Magnetic Resonance (NMR), NH3-Temperature Programmed Desorption (NH3-TPD) and Pyridine-Fourier Transform Infrared Spectroscopy (Py-FTIR). Characterization results indicate that NaOH treatment could improve the mesoporous structure for both ZSM-22 and ZSM-48. NaOH treatment modifies the acidity of ZSM-22 and ZSM-48 diversely. The n-hexane hydroisomerization performances of Pt supported protonic form ZSM-22 and ZSM-48 (Pt/HZSM-22 and Pt/HZSM-48) bifunctional catalysts have been evaluated in a fixed bed reactor. Catalytic results indicate that catalytic activity and selectivity depend on both pore structure and acidity of zeolites. In comparison of Pt/HZSM-22 and Pt/HZSM-48, Pt/HZSM-22 shows better n-hexane hydroisomerization performance at relatively low temperature (<300 °C), meanwhile, at relatively high temperature (>300 °C) Pt/HZSM-48 exhibits better catalytic performance. Moreover, alkali treated Pt/HZSM-48 could produce more di-branched isomer compared with alkali treated Pt/HZSM-22.

Mn/beta and Mn/ZSM-5 for the low-temperature selective catalytic reduction of NO with ammonia: Effect of manganese precursors

Two series of Mn/beta and Mn/ZSM-5 catalysts were prepared to study the influence of how different Mn precursors, introduced to the respective parent zeolites by wet impregnation, affected the selective catalytic reduction (SCR) of NO by NH3 across a low reaction temperature window of 50–350 °C. In this study, the catalysts were characterized using N2 adsorption/desorption, X-ray diffraction, X-ray fluorescence, H2 temperature-programmed reduction, NH3 temperature-programmed desorption and X-ray photoelectron spectroscopy. As the manganese chloride precursor only partially decomposed this primarily resulted in the formation of MnCl2 in addition to the presence of low levels of crystalline Mn3O4, which resulted in poor catalytic performance. However, the manganese nitrate precursor formed crystalline MnO2 as the major phase in addition to a minor presence of unconverted Mn-nitrate. Furthermore, manganese acetate resulted principally in a mixture of amorphous Mn2O3 and MnO2, and crystalline Mn3O4. From all the catalysts screened, the test performance data showed Mn/beta-Ac to exhibit the highest NO conversion (97.5%) at 240 °C, which remained >90% across a temperature window of 220–350 °C. The excellent catalytic performance was ascribed to the enrichment of highly dispersed MnOx (Mn2O3 and MnO2) species that act as the active phase in the NH3-SCR process. Furthermore, together with a suitable amount of weakly acidic centers, higher concentration of surface manganese and a greater presence of surface labile oxygen groups, SCR performance was collectively enhanced at low temperature.

Facile and Low-cost Synthesis of Mesoporous Ti-Mo Bi-metal Oxide Catalysts for Biodiesel Production from Esterification of Free Fatty Acids in Jatropha curcas Crude Oil.

Mesoporous Ti-Mo bi-metal oxides with various titanium-molybdenum ratios were successfully fabricated via a facile approach by using stearic acid as a low-cost template agent. thermal gravity (TG) /differential scanning calorimetry (DSC) analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, nitrogen adsorption-desorption isotherm, NH3 temperature-programmed desorption (NH3-TPD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements indicated these materials possessing mesoporous structure, sufficient pore size and high acid intensity. The catalytic performance of prepared catalysts was evaluated by esterification of free fatty acids in Jatropha curcas crude oil (JCCO) with methanol. The effects of various parameters on FFA conversion were investigated. The esterification conversion of 87.8% was achieved under the condition of 180°C, 2 h, methanol to JCCO molar ratio of 20:1 and 3.0 wt.% catalyst (relative to the weight of JCCO). The mesoporous catalysts were found to exhibit high activities toward the simultaneous esterification and transesterification of JCCO. Furthermore, the catalyst could be recovered with a good reusability.

Ceria-modified hierarchical Hβ zeolite as a robust solid acid catalyst for alkenylation of p-xylene with phenylacetylene

A ceria-modified hierarchical Hβ zeolite was prepared by a desilication-dealumination procedure followed by ceria modification. The catalytic performance of the ceria-modified and unmodified hierarchical Hβ zeolite catalysts for alkenylation of p-xylene with phenylacetylene was investigated. Various characterization techniques, including X-ray diffraction, X-ray fluorescence, nitrogen adsorption-desorption, and NH3 temperature-programmed desorption, were used to examine the structure-performance relationships. Our results show that the optimized ceria-modified hierarchical Hβ zeolite catalyst demonstrated higher catalytic activity, selectivity, and stability for alkenylation of p-xylene with phenylacetylene than those of pristine Hβ zeolite. This performance was attributed to more acidic sites and improved accessibility to active sites through larger pores, together with a higher mesoporous surface area and volume resulting from the hierarchical pore architecture and ceria modification. Thus, our 5 wt% CeO2-Hβ-B0.2A0.2 catalyst shows great potential for producing alkenyl aromatics through solid acid catalyzed alkenylation.

CuFe and CuCo supported on pillared clay as catalysts for CO2 hydrogenation into value-added products in one-step

Value-added products synthesis by the one-step CO2 hydrogenation reaction has attracted much attention of researchers. In this paper, three catalysts: Cu/V-AlPILC,CuFe/V-AlPILC, and CuCo/V-Al PILC, prepared by impregnation method on Al-pillared clay support were studied. The effect of Fe and Co additives on the physicochemical properties of Cu-based catalysts was characterized by X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscope (SEM), N2 adsorption/desorption isotherms, temperature programmed reduction (TPR), Transmission Electron Microscope (TEM), X-ray photoelectron spectroscopy (XPS), N2O decomposition, CO2 and NH3 temperature-programmed desorption (CO2-TPD and NH3-TPD), and Fourier Transform Infrared Spectroscopy after gaseous pyridine adsorption (Py-FTIR) techniques. These catalysts were evaluated for CO2 hydrogenation into value-added products at temperatures ranging from 250 to 300 °C for 3 h and 40 bar pressure. Stability test was performed at 250 °C for 24 h and 40 bar pressure. The catalytic behavior revealed that a linear relationship does exist between the CO2 conversion with the metallic area. The DME and methanol synthesis showed a correlation with the basic and acid sites. The CuFe/V-Al PILC catalyst showed the highest selectivity for methanol and DME at 250 °C.

Highly efficient conversion of glucose into methyl levulinate catalyzed by tin-exchanged montmorillonite

Abstract Tin-exchanged montmorillonite catalysts were prepared by an ion exchange method and examined as solid acid catalysts. The synthesized catalysts were characterized by X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy, N2 adsorption–desorption analysis, powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, NH3 temperature-programmed desorption analysis, and pyridine adsorption Fourier transform infrared spectroscopy. Subsequently, the catalysts were examined for use in the conversion of glucose into methyl levulinate in methanol. A high yield of methyl levulinate of 59.7% was obtained upon conversion of 0.3 g glucose in 24 g methanol over 0.15 g catalyst at 220 °C under 2 MPa N2 for 6 h. The recyclability of the catalyst was also examined, and the conversions of glucose and methanol remained mostly unchanged under repeated usage of the catalyst in five catalytic runs; in contrast, the yield of methyl levulinate decreased slightly. The excellent catalytic performance of the tin-exchanged montmorillonite catalyst was attributed to a combination of the presence of a large amount of acidic sites and balanced amounts of Lewis and Bronsted acid sites on the catalyst.

Octahedral MnO2 Molecular Sieve-Decorated Meso-ZSM-5 Catalyst for Eco-Friendly Synthesis of Pyrazoles and Carbamates

Octahedral MnO2 molecular sieve (hereafter designated as OMS) was prepared in the presence of urea, and mesoporous ZSM-5 (designated as Meso-ZSM-5) was prepared using propyltriethoxysilane as additive under hydrothermal synthesis condition. OMS-decorated Meso-ZSM-5 was prepared by heating a grounded mixture of OMS and Meso-ZSM-5. Powder X-ray diffraction, N2-sorption, SEM, TEM, thermogravimetric analysis, FT-IR, diffuse reflectance UV–vis spectroscopy, and NH3 and CO2 temperature-programmed desorption techniques were used to characterize the material. The catalyst was demonstrated in a one-pot, one-step synthesis of pyrazoles via cyclization followed by dehydrogenation as the key reaction steps. Synthesis of carbamates by the reaction of cyclic and acyclic carbonates/di-tert-butyl dicarbonate with amines was another important application of this catalyst. Catalyst exhibited efficient recyclability. No leaching of active species took place even after five recycles. A strong interface between OMS and Meso-Z...

Synthesis of Ni/H-Zr-MCM-48 and their isomerization activity of n-heptane

H-Zr-MCM-48 was synthesized by ion exchange from Zr-MCM-48 which was synthesized by hydrothermal method and Ni/H-Zr-MCM-48 was synthesized by impregnation method. MCM-48, Zr-MCM-48 and Ni/H-Zr-MCM-48 were characterized by various physicochemical methods including X-ray diffraction (XRD), N2 adsorption–desorption, Fourier transform infrared spectroscopy techniques and NH3 temperature programmed desorption (NH3-TPD), etc for comparison. XRD, TEM and N2 adsorption–desorption results suggest that Zr-MCM-48 samples still maintained typical cubic mesoporous framework of MCM-48, with slight decrease of specific surface areas and mesopore orders. MCM-48, Zr-MCM-48 and Ni/H-Zr-MCM-48 were also investigated by n-heptane isomerization as a probe reaction. Compared with MCM-48, Zr-MCM-48 and H-Zr-MCM-18, Ni/H-Zr-MCM-48 catalyst exhibited significantly higher selectivity for the formation of isoparaffin, with lower coke deposition and excellent catalyst stability.

(Zn, Ni, Cu)-BTC Functionalized with Phosphotungstic Acid for Adsorptive Desulfurization in the Presence of Benzene and Ketone

A novel composite adsorbent, PTA@(Zn, Ni, Cu)-BTC, was prepared by (Zn, Ni, Cu)-BTC doped with different amounts of phosphotungstic acid (PTA) using an impregnation method. Apparatus like nitrogen adsorption–desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), inductively coupled plasma optical emission spectroscopy (ICP-OES), and NH3-temperature programmed desorption (NH3-TPD) are employed to characterize our obtained adsorbents. The adsorption properties of as-prepared adsorbents for the dibenzothiophene (DBT) were evaluated by means of fixed-bed breakthrough experiments. Unlike conventional MOFs (metal–organic frameworks), the PTA@(Zn, Ni, Cu)-BTC exhibited high DBT selectivity adsorption performs with a superior uptake capacity compared with those previously reported in the literatures. Additionally, PTA@(Zn, Ni, Cu)-BTC showed a remarkable stability in the presence of benzene and acetone, maintaining about 95% initial uptake capacity after eight...