CO2 Temperature-programmed Desorption Research Articles

CO2-assisted oxidative dehydrogenation of ethane to ethylene over the ZnO-ZrO2 catalyst

The ZnO-ZrO2 catalyst was prepared by the deposition-precipitation method using ZrO2 as the carrier obtained from calcining commercial zirconium hydroxide (Zr(OH)4). And the catalytic performance was evaluated at 873 K in CO2-assisted ethane oxidative dehydrogenation reaction (CO2-ODHE). The physical-chemical properties and morphology were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectra (XPS), CO2 temperature-programmed desorption (CO2-TPD). The results show that ZnO were doped into the surface lattice of ZrO2 on the 5%ZnO-ZrO2 catalyst, generating highly dispersed ZnO species and oxygen-deficient regions on catalyst surface. 5%ZnO-ZrO2 catalyst could selectively breaking C–H bond instead of C–C bond, delivering excellent catalytic performance. 210 μmol/(gcat·min) of C2H4 formation rate could compare favorably with the data reported on noble metal and transition metal carbides. Additionally, the possible mechanism is discussed.

BCN materials with adjustable active sites as heterogeneous acid–base catalysts for Knoevenagel condensation reaction

The Knoevenagel condensation reaction is one of the most effective methods for the formation of C–C bonds. However, developing efficient heterogeneous catalysts for the Knoevenagel condensation reaction is imperative. In this study, a series of boron carbon nitride (BCN) catalysts with adjustable active sites were designed via molecular self-assembly and calcination-temperature adjustment. The BCN materials synthesized at a calcination temperature of 750 °C (BCN-750) had the largest number of active sites and exhibited excellent activity, with a yield of 96% in the condensation reaction of benzaldehyde and malononitrile in only 4 min at room temperature. The excellent catalytic activity was attributed to the B and N species at the B–N–C sites, which functioned as acids and bases, respectively, to catalyze the Knoevenagel condensation reaction. This result was confirmed by temperature-programmed desorption of CO2 (CO2 TPD), temperature-programmed desorption of NH3 (NH3 TPD), X-ray photoelectron spectroscopy (XPS), and 11B solid-state magic-angle spinning nuclear magnetic resonance spectroscopy. In addition, aromatic and aliphatic aldehydes were successfully converted into their corresponding products. Analysis of the catalytic mechanism revealed that the deprotonation of malononitrile to form a carbanion was the rate-determining step.

Transfer hydrogenation of furfural to furfuryl alcohol under microwave irradiation using mixed oxides.

The reaction to obtain furan alcohols is one of the most important in the upgrading of furan derivates. An attractive route is the transfer hydrogenation of furfural using acidic-basic catalysts. In this work, mixed oxides derived from ternary hydrotalcites were employed to obtain furfuryl alcohol from furfural assisted by microwave irradiation. The reaction was studied using containing Co2+ and Ni2+ in their structure and was then optimized using distinct primary and secondary alcohols as hydrogen donor sources, as well as distinct temperatures and initial concentrations of furfural. The yields to furfuryl alcohol are strongly dependent on the type of Me2+ in layered oxides mainly due to higher basicity and also to the donor employed in the reaction. The mixed oxide containing Co2+ showed complete conversion of furfural and higher yields to furfuryl alcohol (> 95%) at short times of reaction (< 1 h).

Glycerol conversion in the presence of ethanol over CoFe2O4/SBA-15 mesoporous catalyst: Effect of the co-reagent on the catalytic performance

The synthesis and characterization of cobalt ferrite supported on mesoporous SBA-15 was presented to act as a catalyst in the glycerol conversion reaction in the presence of ethanol. Characterizations via X-ray diffraction (XRD) and FTIR spectroscopy confirmed the syntheses of SBA-15 and the CoFe2O4 phase dispersed on porous silica. Raman spectroscopy showed the ferrite with a degree of inversion (δ) of 0.4. The redox property was evaluated by TPR-H2 which exhibited reduction events above 400 °C, referring to the reduction of Co2+ and Fe3+ species. N2 physisorption analysis showed a surface area of 372 m2/g and a total pore volume of 0.65 cm3/g, indicating the presence of oxide on the surface and in the mesochannels of the support. Scanning electron microscopy (SEM) confirmed maintenance of support morphology after the impregnation process, while transmission electron microscopy (TEM) showed an average particle size of 6 nm for the supported cobalt ferrite. TEM images also confirmed that the typical mesoporosity of SBA-15 was maintained after spinel insertion. The acid-base properties of the catalyst indicated the presence of weak basic sites by CO2 temperature-programmed desorption (TPD-CO2) and the presence of Lewis acid sites by NO and Pyridine adsorption followed by FTIR analysis. The catalytic tests showed greater performance for the conversion glycerol in the presence of ethanol as co-reagent, considering that ethanol favors the interaction of glycerol with the solid surface and benefits the catalytic cycle. The reaction showed a conversion of only 20% in the absence of ethanol, while in the presence of the cosolvent a conversion greater than 80% was observed.

Preparation of Ce-MnOx Composite Oxides via Coprecipitation and Their Catalytic Performance for CO Oxidation.

Ce-MnOx composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60-140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation performance of CO was investigated using X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), H2 temperature programmed reduction (H2-TPR), CO-temperature programmed desorption (CO-TPD), and in situ infrared spectra. The experimental results reveal that under the same test conditions, the CO conversion rate of pure Mn3O4 reaches 95.4% at 170 °C. Additionally, at 140 °C, the Ce-MnOx series composite oxide catalyst converts CO at a rate of over 96%, outperforming single-phase Mn3O4 in terms of catalytic performance. With the decrement in Ce content, the performance of Ce-MnOx series composite oxide catalysts first increase and then decrease. The Ce MnOx catalyst behaves best when Ce:Mn = 1:1, with a CO conversion rate of 99.96% at 140 °C and 91.98% at 100 °C.

Promotion effects of alkali metals on iron molybdate catalysts for CO2 catalytic hydrogenation

CO2 hydrogenation is an attractive way to store and utilize carbon dioxide generated by industrial processes, as well as to produce valuable chemicals from renewable and abundant resources. Iron catalysts are commonly used for the hydrogenation of carbon oxides to hydrocarbons. Iron-molybdenum catalysts have found numerous applications in catalysis, but have been never evaluated in the CO2 hydrogenation. In this work, the structural properties of iron-molybdenum catalysts without and with a promoting alkali metal (Li, Na, K, Rb, or Cs) were characterized using X-ray diffraction, hydrogen temperature-programmed reduction, CO2 temperature-programmed desorption, in-situ 57Fe Mossbauer spectroscopy and operando X-ray adsorption spectroscopy. Their catalytic performance was evaluated in the CO2 hydrogenation. During the reaction conditions, the catalysts undergo the formation of an iron (II) molybdate structure, accompanied by a partial reduction of molybdenum and carbidization of iron. The rate of CO2 conversion and product selectivity strongly depend on the promoting alkali metals, and electronegativity was identified as an important factor affecting the catalytic performance. Higher CO2 conversion rates were observed with the promoters having higher electronegativity, while low electronegativity of alkali metals favors higher light olefin selectivity.

Steel Slag Decorated with Calcium Oxide and Cerium Oxide as a Solid Base for Effective Transesterification of Palm Oil

For further resource utilization of solid waste steel slag and the reduction in biodiesel production costs, this study used steel slag as a carrier to synthesize a CaO-CeO2/slag solid base catalyst for the effective transesterification of palm oil into fatty acid methyl esters (FAMEs). The synthesis involved a two-step impregnation of steel slag with nitrate of calcium and cerium and thermal activation at 800 °C for 180 min. Then, the catalysts’ textural, chemical, and CO2 temperature-programmed desorption properties were characterized. The catalytic activity depended highly on the ratio of Ca-Ce to steel slag mass; the CaO-CeO2/slag-0.8 catalyst showed outstanding performance. Characterization showed that the surface area and total basicity of the Ca-Ce/slag-0.8 catalyst were 3.66 m2/g and 1.289 mmol/g, respectively. The reactivity results showed that FAMEs obtained using 7 wt.% catalyst, 9:1 of methanol-to-palm-oil molar ratio, 180 min reaction duration, and 70 °C reaction temperature was optimum (i.e., 95.3% yield). In addition, the CaO-CeO2/slag-0.8 catalyst could be reused for at least three cycles, retaining 91.2% of FAMEs yield after n-hexane washing. Hence, the catalyst exhibits an excellent potential for cost-effective and environmentally friendly biodiesel production.

Plasma-catalytic synthesis of ammonia over Ru/BaTiO3-based bimetallic catalysts: Synergistic effect from dual-metal active sites

Plasma-catalytic synthesis of ammonia (NH3) was carried out using BaTiO3 supported Ru-M bimetallic catalysts (Ru-M/BaTiO3, M = Fe, Co and Ni) in a dielectric barrier discharge (DBD) reactor. The NH3 synthesis performance followed the order of Ru-Ni/BaTiO3 > Ru/BaTiO3 > Ru-Co/BaTiO3 > Ru-Fe/BaTiO3, with the highest NH3 concentration (3895 ppm) and energy yield (0.39 g kWh−1) achieved over Ru-Ni/BaTiO3 at 25 W and 10 W, respectively. To gain insights into the physio-chemical properties of the Ru-M/BaTiO3 catalysts, comprehensive catalyst characterizations were performed, including X-ray diffraction, N2 physisorption measurements, X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), and temperature-programmed desorption of CO2 and N2 (CO2 and N2-TPD). The results indicated that the loading of Ni enhanced the basicity and N2 adsorption capacity of the catalyst, as well as the density of oxygen vacancy (OV) on the BaTiO3 surface, which facilitated the adsorption and activation of N2 on catalyst surface. These effects led to the enhanced NH3 synthesis, as excited N2 could be adsorbed on Ru-Ni/BaTiO3 from plasma region and stepwise hydrogenated to form NHx species and ultimately NH3.

Non-thermal plasma catalytic dry reforming of methane over Ni-Co3O4 supported modified-titania catalysts: Effect of process conditions on syngas production

The dry reforming of methane has been studied over modified TiO2-supported 10%Ni-5%Co3O4 composite catalysts using a non-thermal plasma dielectric barrier discharge fixed-bed reactor. The 10%Ni-5%Co3O4/modified-TiO2 nanorods (NR) have been synthesized by hydrothermal method. Physicochemical characterizations of the composite catalysts have been conducted by X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), CO2 temperature-programmed desorption (CO2-TPD), high-resolution transmission electron microscopy (HRTEM) and N2 adsorption-desorption (BET) analysis. Incorporation of cubic-structured Co3O4 into Ni/TiO2 attributes to the enhancement of basicity, reducibility and metal-support interaction. Consequently, the catalytic activity of 10%Ni-5%Co3O4/TiO2 NR increases and confer CH4 and CO2 conversions at 86.4% and 84.9%, respectively. Meanwhile, the H2 and CO selectivity are reported as 50.1% and 49.0% respectively. Higher syngas ratio (H2/CO) from 0.84 to 1.01 and 26% increment in overall energy efficiency compared to plasma DRM alone have been observed. The superior plasma DRM performance is correlated to the greater basicity properties and the synergistic effect of non-thermal plasma with the 10%Ni-5%Co3O4/modified-TiO2 catalyst composite.

Hybrid Plasma-Catalytic CO2 Dissociation over Basic Metal Oxides Combined with CeO2

The problem of CO2 waste in the atmosphere is a major concern, and methods of CO2 utilization are being currently developed. In the present work, a plasma-catalytic process is applied for CO2 dissociation. A series of MgO and CeO2-containing catalysts were synthesized, and the samples were characterized by: a low-temperature N2 adsorption-desorption analysis, X-ray diffraction, X-ray photoelectron spectroscopy, temperature-programmed desorption of CO2, and X-ray fluorescence spectroscopy. It was stated that under dielectric barrier discharge conditions, the catalyst surface, composition, and phase content remain unchanged. The superior catalytic activity of the MgCe-Al sample is attributed to the combination of weak basic sites and oxygen vacancies on the catalyst surface.

Tailoring basic and acidic properties of MgAl hydrotalcite by fluoride anions: Effect on glycerol oligomerisation

In this work, two families of catalysts based on mixed metal oxides derived from MgAl hydrotalcites were synthesized with a Mg/Al molar ratio of 3. On the one hand, in the first family, the fluoride anion was incorporated in the interlayer space by using ammonium fluoride, exploiting the “memory effect” characteristic of hydrotalcites. In the second family, fluoride anions substituted oxides anions in the layer, incorporating directly them during the precipitation of hydroxides, by using cryolite as a precursor for both fluorine and aluminium. The hydrotalcites were transformed into mixed metal oxides by thermal treatment and tested in the glycerol etherification reaction at 230 ºC, in a batch reactor at atmospheric pressure. The hydrotalcites and the corresponding mixed metal oxides were characterized by different experimental techniques, such as X-ray diffraction (XRD), elemental analysis (CHF), N2 sorption at − 196 ºC, thermogravimetric analysis (ATD-TG), X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of CO2 and NH3 (CO2-TPD and NH3-DTP) and solid state nuclear magnetic resonace (ssNMR) of 19F. It was found that the mixed metal oxides prepared from hydrotalcites, where fluorine was incorporated in the synthesis step using cryolite, achieved the maximum conversion values and complete selectivity towards diglycerol. Diglycerols were the unique detected products and, in some cases, the formation of triglycerols was also detected.

Promoting effect exerted by WOx on Pt/ZrO2 catalysts during NOx reduction using H2 in the excess of O2

This work addresses the reduction of NOx by H2 under O2-rich conditions below 200 °C using Pt/W/ZrO2 catalysts with tungsten loadings from 0 to 14 wt%. Samples were thoroughly characterized by N2 physisorption, temperature-programmed desorption of CO, X-ray diffraction, laser Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) with CO as probe molecule. Catalytic investigations showed the highest efficiency for the sample with 5 wt% W providing NOx conversion of 94 % and N2O selectivity of 15 %. The effect of W promoter is mostly attributed to structural promotion by isolated WO6 entities stabilizing the ZrO2 surface and leading to a high number of active Pt sites. By contrast, negligible electronic interaction between the promoter and Pt sites appears. Moreover, DRIFTS studies suggest that, in addition to the predominate NOx reduction by H2 on Pt sites, a side reaction occurs including NHx species formed at the interface of Pt and WOx/ZrO2.

Ethanol Coupling Reactions over MgO-Al2O3 Mixed Oxide-Based Catalysts for Producing Biofuel Additives.

Catalytic conversion of ethanol to 1-butanol was studied over MgO-Al2O3 mixed oxide-based catalysts. Relationships between acid-base and catalytic properties and the effect of active metal on the hydrogen transfer reaction steps were investigated. The acid-base properties were studied by temperature-programmed desorption of CO2 and NH3 and by the FT-IR spectroscopic examination of adsorbed pyridine. Dispersion of the metal promoter (Pd, Pt, Ru, Ni) was determined by CO pulse chemisorption. The ethanol coupling reaction was studied using a flow-through microreactor system, He or H2 carrier gas, WHSV = 1 gEtOH·gcat.-1·h-1, at 21 bar, and 200-350 °C. Formation and transformation of surface species under catalytic conditions were studied by DRIFT spectroscopy. The highest butanol selectivity and yield was observed when the MgO-Al2O3 catalyst contained a relatively high amount of strong-base and medium-strong Lewis acid sites. The presence of metal improved the activity both in He and H2; however, the butanol selectivity significantly decreased at temperatures ≥ 300 °C due to acceleration of undesired side reactions. DRIFT spectroscopic results showed that the active metal promoted H-transfer from H2 over the narrow temperature range of 200-250 °C, where the equilibrium allowed significant concentrations of both dehydrogenated and hydrogenated products.

Origin of Higher CO Oxidation Activity of Pt/Rutile than That of Pt/Anatase

Herein, we show that the weak interaction of CO with Pt/TiO2 under the CO oxidation condition is the origin of higher CO oxidation activity of Pt/rutile than that of Pt/anatase. The results of CO temperature-programmed desorption (TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) indicate that the onset temperatures of CO desorption on freshly prepared Pt/rutile and Pt/anatase are the same. However, the CO-TPD curves of Pt/rutile after the reaction test show that the desorption temperature of CO shifts to a lower temperature, while that for Pt/anatase does not change. The in situ pulse reaction using DRIFTS reveals that CO on Pt/rutile reacted with oxygen faster than CO on Pt/anatase. IR spectra with peak deconvolution of adsorbed CO on Pt/rutile exhibit that CO adsorbed on the terrace sites of Pt clusters on rutile (2089 cm–1) reacts readily with O2. These results indicate that the higher low-temperature activity of Pt/rutile is related to its weaker interaction with CO compared with Pt/anatase under the reaction conditions. Our findings deepen the fundamental understanding of metal–support interaction and CO oxidation on Pt/TiO2 catalysts.

Effect of MgFe-LDH with Reduction Pretreatment on the Catalytic Performance in Syngas to Light Olefins

MgFe-layered double hydroxides (LDH) were widely used as catalysts for Fischer–Tropsch synthesis to produce light olefins, in which the state of Fe-species may affect the resulting catalytic active sites. Herein, the typical MgFe-LDH was hydrothermally synthesized and the obtained MgFe-LDH was pretreated with H2 at different temperatures to reveal the effects of the state of Fe-species on the catalytic performance in Fischer–Tropsch synthesis. MgFe-LDH materials were characterized by X-ray diffraction (XRD), N2 adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2 temperature-programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). It was found that a MgO-FeO solid solution would be formed with the increase of the reduction temperature, which made the electrons transfer from Mg atoms to Fe atoms and strengthened the adsorption of CO. The pre-reduced treatment toward Mg-Fe-LDH enabled the FeCx active sites to be easily formed in situ during the reaction process, leading to the high conversion of CO. CO2 temperature-programmed desorption (CO2-TPD) and H2 temperature-programmed desorption (H2-TPD) analysis confirmed that the surface basicity of the catalysts was increased and the hydrogenation capacity was weakened, the secondary hydrogenation of the olefins was inhibited, and therefore as were the enhancement of O/P in the product and the high selectivity of light olefins (42.7%).

Activated Carbon Produced from the Hydrothermal Treatment of Glucose with KOH Activation for Catalytic Absorption of CO2 in a BEA-AMP Bi-Solvent Blend.

The amine-based postcombustion CO2 capture (PCC) process involves absorption of CO2 into a solvent and then regenerating the solvent to produce CO2. In this study, the effect of an activated carbon (AC) catalyst, synthesized through hydrothermal treatment and furnace activation on CO2 absorption in a 4M BEA/AMP amine blend, was evaluated and compared with that of a KMgO/CNTs (1:4) catalyst. The physical and chemical properties of AC were investigated with a scanning electron microscope (SEM), CO2 temperature-programmed desorption (CO2-TPD), Brunauer-Emmett-Teller (BET), powder X-ray diffraction (XRD), and thermogravimetric analyzer (TGA) and compared with the KMgO/CNTs (1:4) catalyst. The results showed that when compared against noncatalytic CO2 absorption, AC enhanced the linear rate of CO2 absorption by 33.3%, while for KMgO/CNTs, it was reported as 25.5%. The relatively higher surface area, combined with the higher number and strength of basic sites of AC relative to the KMgO/CNTs (1:4) catalyst, provided effective basic reaction sites for CO2 absorption, thereby enhancing the rate of CO2 absorption into the amine. AC was also relatively easier to synthesize which would provide a good replacement for the CNT-based catalyst which has carcinogenic tendencies.

Mechanochemical Synthesized CaO/ZnCo2O4 Nanocomposites for Biodiesel Production

Biodiesel has been recognized as an environmentally friendly, renewable alternative to fossil fuels. In this work, CaO/ZnCo2O4 nanocomposites were successfully synthesized via simple mechanochemical reaction between ZnCo2O4 and CaO powders by varying the CaO loading from 5 to 20 wt.%. The synthesized materials were found to be highly efficient heterogeneous catalysts for transesterification of tributyrin with methanol to produce biodiesel. The nanocomposite, which contained 20 wt.% CaO and 80 wt.% ZnCo2O4 (CaO/ZnCo2O4-20), exhibited superior and stable transesterification activity (98% conversion) under optimized reaction conditions (1:12 TBT to methanol molar ratio, 5 wt.% catalyst and 180 min. reaction time). The experimental results revealed that the reaction mechanism on the CaO/ZnCo2O4 composite followed pseudo first-order kinetics. The physicochemical characteristics of the synthesized nanocomposites were measured using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), Fourier-transformed infrared spectroscopy (FTIR), X-ray photoelectron spectrometer (XPS), N2-physisorption, and CO2- temperature-programmed desorption (CO2-TPD) techniques. The results indicated the existence of coalescence between the CaO and ZnCo2O4 particles, Additionally, the CaO/ZnCo2O4-20 catalyst was found to possess the greater number of highly basic sites and high porosity, which are the key factors affecting catalytic performance in transesterification reactions.

Bimetallic Metal-Organic Framework Derived Nanocatalyst for CO2 Fixation through Benzimidazole Formation and Methanation of CO2

In this paper, a bimetallic Metal-Organic Framework (MOF) CoNiBTC was employed as a precursor for the fabrication of bimetallic nanoalloys CoNi@C evenly disseminated in carbon shells. These functional nanomaterials are characterized by powdered X-ray diffraction (PXRD), Fourier Transform Infra-Red spectroscopy (FTIR), surface area porosity analyzer, X-ray photoelectron spectroscopy (XPS), Field emission scanning electron microscopy (FESEM), Transmission electron microscopy (TEM), Hydrogen Temperature-Programmed Reduction (H2 TPR), CO2 Temperature-Programmed Desorption (CO2-TPD), and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This nanocatalyst was utilized in the synthesis of benzimidazole from o-phenylenediamine in the presence of CO2 and H2 in a good yield of 81%. The catalyst was also efficient in the manufacture of several substituted benzimidazoles with high yield. Due to the existence of a bimetallic nanoalloy of Co and Ni, this catalyst was also employed in the methanation of CO2 with high selectivity (99.7%).

Performance of Modified Alumina-Supported Ruthenium Catalysts in the Reforming of Methane with CO2

Ruthenium (1 wt%) catalysts supported on alumina doped with alkaline (Na and K) and alkaline earth metals (Ba, Ca, and Mg) of different concentrations (1, 5, and 10 wt%) were tested in the dry reforming of methane. All catalysts were prepared by the successive impregnation method. Supports were characterized by X-ray diffraction, BET surface area, temperature-programmed desorption of CO2, and 2-propanol dehydration. Additionally, catalysts were characterized by temperature-programmed reduction (TPR), temperature-programmed oxidation (TPO), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Stability tests to study coke deposition were performed using long-time dry reforming reactions. All the catalysts showed good catalytic activity, and activity falls were never detected. Ru metallic phase seemed to be resistant to coke formation even though its particles are sintered during a long-term reaction.

Core-Sheath Pt-CeO2/Mesoporous SiO2 Electrospun Nanofibers as Catalysts for the Reverse Water Gas Shift Reaction.

One-dimensional (1D) core-sheath nanofibers, platinum (Pt)-loaded ceria (CeO2) sheath on mesoporous silica (SiO2) core were fabricated, characterized, and used as catalysts for the reverse water gas shift reaction (RWGS). CeO2 nanofibers (NFs) were first prepared by electrospinning (ES), and then Pt nanoparticles were loaded on the CeO2 NFs using two different deposition methods: wet impregnation and solvothermal. A mesoporous SiO2 sheath layer was then deposited by sol-gel process. The phase composition, structural, and morphological properties of synthesized materials were investigated by scanning electron microscope (SEM), scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), nitrogen adsorption/desorption method, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis, and CO2 temperature programmed desorption (CO2-TPD). The results of these characterization techniques revealed that the core-sheath NFs with a core diameter between 100 and 300 nm and a sheath thickness of about 40-100 nm with a Pt loading of around 0.5 wt.% were successfully obtained. The impregnated catalyst, Pt-CeO2 NF@mesoporous SiO2, showed the best catalytic performance with a CO2 conversion of 8.9% at 350 °C, as compared to the sample prepared by the Solvothermal method. More than 99% selectivity of CO was achieved for all core-sheath NF-catalysts.