Incipient Wetness Impregnation Method Research Articles

Effect of preparation conditions of nanocrystalline Pd/MgO catalysts on their performance in selective hydrogenation of acetylene

In the present work, an alkoxide sol-gel method was applied to prepare Pd/MgO catalysts. The sol-gel procedure was followed by supercritical drying (aerogels) or conventional drying (xerogels) in a furnace. These materials were compared with the impregnated samples. The Pd loading was 1 wt% in all the cases. The as-prepared catalysts were characterized by a set of physicochemical methods. Both the type of the Pd precursor and the preparation route were found to affect the porous structure of the materials as well as the dispersion of the palladium particles and their localization over the MgO support. Both the xerogel and incipient wetness impregnation methods lead to a narrower pore size distribution in comparison to the aerogel technique. The most dispersed particles with an average size of ∼ 2.0–2.2 nm were observed for the samples prepared by xerogel and impregnation methods. In the case of aerogel-prepared samples, metallic palladium particles possess bimodal distribution with average diameters of 4.3 and 8.4 nm. The best catalytic performance in acetylene hydrogenation to ethylene (50 % acetylene conversion at 37 °C with selectivity ∼60 %) was observed for the Pd/MgO catalyst prepared via the aerogel route using [Pd(NH3)4](NO3)2. Compared to other samples, this material is characterized by relatively weak metal-support interactions and the availability of active sites for reactants, which ensures the kinetic mode of the hydrogenation reaction (Ea = 74.9 kJ/mol).

High-Performance Ir1/CeO2 Single-Atom Catalyst for the Oxidation of Toluene.

The elimination of toluene is an obligatory target with increasing VOC emission in recent years. This study successfully prepared a single-atom Ir catalyst (Ir1/CeO2) by a simple incipient wetness impregnation method, confirmed by in situ CO DRIFTS and AC-HAADF-STEM. Compared to the cluster Ir catalyst (Ir/CeO2-C), Ir1/CeO2 exhibited excellent catalytic performance, stability, and water resistance for the oxidation of toluene. By Raman, H2-TPR, O2-TPD, and XPS experiments, abundant oxygen defects and a unique Ir3+-Ov-Ce3+ structure were formed for the Ir1/CeO2 sample because it had a lower oxygen vacancy formation energy. Furthermore, the DFT results revealed that the Ir1/CeO2 sample had a lower ring-opening energy barrier and adsorption energy of the ring-opening products, which was the rate-determining step for the oxidation of toluene. This work provides instructive insights into the construction of Ir/CeO2 catalysts for the highly efficient removal of VOCs.

Boosting the selective hydrogenation of biphenyl to cyclohexylbenzene over bimetallic Ni-Ru/SiO2 catalyst via enhancing strong metal-support interaction

Tuning the metal-support interaction (MSI) between highly dispersed nanosized metal particles and the support plays a pivotal role in the activity and selectivity of polyaromatics selective hydrogenation. In this work, the supported bimetallic Ni-Ru/SiO2-SEA catalyst was prepared by a strong electrostatic adsorption (SEA) strategy, and applied for the selective hydrogenation of biphenyl (BP) to cyclohexylbenzene (CHB). Compared to the catalysts prepared by the conventional incipient wetness impregnation method and Ni/SiO2-SEA, the significant effects of MSI and hydrogen spillover on Ni-Ru/SiO2-SEA facilitated the highly exposed and uniformly dispersed electron-deficient Niδ+ (0 < δ < 2) species, which could enhance adsorption and activation of the electron-withdrawing phenyl group and H2, thereby promoting the efficient and selective conversion of BP to CHB. At the conditions of 160 ℃ and 2 MPa H2 pressure, BP conversion over Ni-Ru/SiO2-SEA reached nearly 100 % within 3 h, achieving a remarkable selectivity of 97.9 % towards CHB, along with a high turnover frequency of 2756.9 h−1 for the active metallic Ni sites. Importantly, according to the kinetic simulations, the hydrogenation rate constant of Ni-Ru/SiO2-SEA was the highest (2.76 × 10-2 mol·g−1·h−1) among the employed catalysts. Moreover, after six consecutive cycles, no obvious decline in hydrogenation efficiency was observed, confirming the remarkable activity and stability of Ni-Ru/SiO2-SEA. Furthermore, the activation of BP and desorption of CHB pathway on the Niδ+ species were elaborated through temperature-programmed desorption characterization, highlighting the prominent contribution of MSI in enhancing the selective hydrogenation of polyaromatics.

Inhibition of methane formation during the water gas shift reaction by Sn doping of Co-CeO2 catalysts

Co-Ce-Sn catalysts were developed for application in the water gas shift reaction (WGSR) at intermediate temperatures (350–400 °C). Ceria-based supports with tin loadings ranging from 2.5% to 30% mol (CeSn(X%)) were synthesized via co-precipitation. Using these supports, cobalt catalysts were developed using the incipient wetness impregnation method, yielding Co-Ce-Sn catalysts (15Co/CeSn(X%)). Physicochemical techniques were employed to characterize the supports and catalysts. XRD and Raman spectroscopy analyses confirmed the presence of solid solutions between CeO2-SnO2 oxides. Notably, a higher Sn loading increased specific surface area and decreased support basicity. H2-TPR and XPS analyses of the catalysts indicated a higher metal-support interaction in the presence of tin. Under all conditions evaluated, the 15Co/CeSn(5%) material was active and presented 100% selectivity towards H2. While the 15Co/CeO2 material presented methane formation. Both samples were stable over 15 hours in the WGSR at 350°C. These findings suggest that the tin loading enhances hydrogen selectivity compared to samples without tin, due to the inhibition of methane formation. Raman spectroscopy analysis of used samples revealed the presence of carbon deposits in the 15Co/CeO2 sample but not in the 15Co/CeSn(5%) sample, suggesting that tin would also have disfavored the carbon formation during the WGSR.

Date Palm Leaflet-Derived Carbon Microspheres Activated Using Phosphoric Acid for Efficient Lead (II) Adsorption

The removal of lead metals from wastewater was carried out with carbon microspheres (CMs) prepared from date palm leaflets using a hydrothermal carbonization process (HTC). The prepared CMs were subsequently activated with phosphoric acid using the incipient wetness impregnation method. The prepared sample had a low Brunauer–Emmet–Teller (BET) surface area of 2.21 m2·g−1, which increased substantially to 808 m2·g−1 after the activation process. Various characterization techniques, such as scanning electron microscopy, BET analysis, Fourier transform infrared, and elemental analysis (CHNS), were used to evaluate the morphological structure and physico-chemical properties of the CMs before and after activation. The increase in surface area is an indicator of the activation process, which enhances the absorption properties of the material. The results demonstrated that the activated CMs had a notable adsorption capacity, with a maximum adsorption capacity of 136 mg·g−1 for lead (II) ions. This finding suggests that the activated CMs are highly effective in removing lead pollutants from water. This research underscores the promise of utilizing activated carbon materials extracted from palm leaflets as an eco-friendly method with high potential for water purification, specifically in eliminating heavy metal pollutants, particularly lead (II), contributing to sustainability through biomass reuse.

Engineered Ru on HY zeolite catalyst for continuous and selective hydrodeoxygenation of lignin phenolics to cycloalkanes under moderate conditions

We report a continuous selective hydrodeoxygenation (HDO) process of guaiacol conversion to cycloalkanes under 180 °C/1 MPa, which results in improved HDO chemistry for lignin-based jet fuel production. The incipient wetness impregnation method was modified to prepare an HY zeolite-supported Ru catalyst with better metal dispersion and acid site uniformity, which overcomes the low conversion and selectivity of previous literature. The modified catalyst (Ru-HY-60-MI) was tested in a continuous fixed bed reactor, resulting in increased HDO conversion of guaiacol to cycloalkanes compared to the unmodified catalyst. Pressure, temperature, and weight hourly space velocity-dependent tests validate guaiacol HDO over Ru-HY-60-MI catalyzed ring hydrogenation of guaiacol to 2-methoxycyclohexanol, acid-catalyzed demethoxylation and dehydration to cyclohexene, and further hydrogenation of cyclohexene to cyclohexane. These experiments enable exploring a continuous HDO process, demonstrate effectiveness for other β-β and α-O-4 lignin representatives and real lignin bio-oil, and pave the way towards commercialization of lignin-based jet fuel.

Synthesis and evaluation of novel Cu-based adsorbent-containing catalysts for CO2 hydrogenation to methanol and value-added products

In this work, sequential incipient wetness impregnation method was used to synthesize Cu/Al2O3, Cu/Na2O/Al2O3 and Cu/CaO/Al2O3 catalysts in different compositions for CO2 conversion to value-added products. Synthesized catalysts were characterized using various analytical techniques and their performances for CO2 catalytic conversion were tested in a high-pressure packed bed reactor under reaction conditions of P = 60 bars, T = 300 °C, and H2/CO2 = 3. The obtained results revealed that the type of adsorbent had a significant impact on CO2 conversion, with CaO-containing catalyst being more efficient for methanol selectivity. Increased Cu content from 10 wt% to 30 wt% with fixed CaO content of 10 wt% resulted in a small increase in CO2 conversion where the highest CO2 conversion of 16.44% and the highest methanol selectivity (17.75%) were obtained for catalyst containing 20 wt% of copper. The best performing catalyst was further promoted using 0.5 wt% Rh promoter which improved both methanol selectivity and space time yield to 23.2% and 0.08 gMeOHgcat−1h−1, respectively. The comparative high performance of the Rh-promoted catalyst was attributed to smaller metal oxide particle size with uniform dispersion, presence of effective hydrogen spill over, moderate basic sites, surface defects and presence of induced copper species.

Efficient catalytic oxidative desulfurization of liquid fuels over tungsten oxide supported on metakaolin surface

AbstractA new high yield and inexpensive composite was fabricated by supporting tungsten oxide on metakaolin via the incipient wetness impregnation method to use in oxidative desulfurization reaction and produce ultra‐clean fuel. The prepared catalyst was characterized by various techniques like XRD, FTIR, FESEM, EDX and N2 adsorption–desorption isotherms, which indicated the catalyst was properly constructed. Initially, desulfurization was examined by loading different amounts of tungsten on the metakaolin surface. Based on the results, 15 % W/metakaolin showed high catalytic activity for the model and real fuels. Moreover, the influence of the main operating variables was studied through the Box–Behnken experimental design. The maximum sulfur removal reached to 99.3 % at a reaction temperature of 60 °C, oxidant to sulfur molar ratio12, catalyst dosage 0.04 g and oxidation time 40 min. Desulfurization from gasoline and gas oil with initial sulfur contents of 300 ppm and 7550 ppm was done under optimum conditions, which represented an efficiency of 60 % and 74 %, respectively. Performing the recycling tests proved the great durability of the catalyst after five runs. This research sheds light that the employed catalyst has excellent activity for industrial applications in the desulfurization process.

Tailoring Cu immobilized MCM-41-based mesostructured catalysts for selective hydrogenolysis of biomass-derived furfural

The CuO-supported MCM-41 catalysts were prepared using a simple incipient wet impregnation method. The catalysts were investigated for hydrogenation of furfural to furfuryl alcohol synthesis. Among all the catalysts, the 2.5% CuO/MCM-41 catalyst shows the best catalytic performance with 92.5% conversion and 89% selectivity of furfuryl alcohol at 210 °C. The catalyst also demonstrated a high turnover frequency (TOF) of 154.4 h−1. The 2.5% CuO/MCM-41 catalyst remained stable for up to 20 h during the time on stream.

The Green Preparation of Mesoporous WO3/SiO2 and Its Application in Oxidative Desulfurization

Recently, supported WO3-based catalysts have been widely used in oxidative desulfurization (ODS) due to their advantages of easy separation, high activity, and being environment-friendly. In this work, supported mesoporous WO3/SiO2 catalysts have been prepared using an incipient-wetness impregnation method with agricultural waste rice husks as both a silicon source and mesoporous template, and phosphotungstic acid as a tungsten source. The effects of different calcination temperatures and WO3 loadings on the ODS performance of samples are studied, and the appropriate calcination temperature and WO3 loading are 923 K and 15.0 wt.%, respectively. The relevant characterization results show that, compared with pure WO3, the specific surface area and mesopore volume of WO3/SiO2 samples are greatly increased. Due to (a) high WO3 loading, (b) high specific surface area, and (c) nanoscale WO3 grains uniformly dispersed on the surface of the mesoporous SiO2 carrier, active sites of WO3/SiO2 catalysts are greatly increased, and their catalytic activities are improved. After the sixth and eighth runs in the ODS of dibenzothiophene and 4,6-dimethyldibenzothiophene, respectively, the WO3/SiO2 catalyst still maintains high catalytic activity (&gt;99.0%) despite the presence of a partial loss of WO3. In addition, with the aid of the UV-Vis technique, the tungsten-peroxo species, the active intermediates in the ODS reaction catalyzed by the WO3/SiO2 catalyst, are captured. Finally, a possible mechanism for the ODS of bulky organic sulfides using the WO3/SiO2 catalyst is proposed.

The Effect of Precursor Concentration on the Crystallite Size of CeO2 to Enhance the Sulfur Resistance of Pt/CeO2 for Water Gas Shift

To develop customized sulfur–resistant catalysts for the water gas shift (WGS) reaction in the waste–to–hydrogen process, the effects of changing the nucleation conditions of the CeO2 support on catalytic performance were investigated. Supersaturation is a critical kinetic parameter for nuclei formation. The degree of supersaturation of the CeO2 precipitation solution was controlled by varying the cerium precursor concentration from 0.02 to 0.20 M. Next, 2 wt.% of Pt was impregnated on those various CeO2 supports by the incipient wetness impregnation method. The prepared samples were then evaluated in a WGS reaction using waste–derived synthesis gas containing 500 ppm H2S. The Pt catalyst supported by CeO2 prepared at the highest precursor concentration of 0.20 M exhibited the best sulfur resistance and catalytic activity regeneration. The sulfur tolerance of the catalyst demonstrated a close correlation with its oxygen storage capacity and easier reducibility. The formation of oxygen vacancies in CeO2 supports is promoted by the formation of small crystals due to a high degree of supersaturation.

Effect of Residence Time and Carrier Gas on the Dehydrogenation of n-Hexane over Alumina-supported Chromium Catalyst

CrOx/γ-Al2O3 catalyst was prepared by incipient wetness impregnation method, and the influence of residence time and carrier gas on the dehydrogenation of n-hexane were studied. It is found that n-hexane dehydrogenation over CrOx/γ-Al2O3 catalyst with H2 as carrier gas exhibits totally different catalytic behaviors with that of diluting n-hexane with N2. When diluting feed with N2, the selectivity to dehydrogenation product is promoted while the cracking reaction is exhibited with reducing residence time. However, the selectivity to dehydrogenation product is significantly decreased while the isomerization of n-hexane is promoted when using H2 as carrier gas. It is proposed that H2 undergoes dissociation on the dehydrogenation active site, and further facilitates the olefinic dehydrogenation products to form carbocation, which performing isomerization reaction on the acid site on the γ-Al2O3 surface. Therefore, the isomerization of n-hexane is promoted in cost of the selectivity to dehydrogenation product when using H2 as carrier gas.

Active nanointerfaces sites for low-temperature water-gas shift reaction over inverse configuration Nb–CeO2/Cu catalysts

A comparative investigation of inverse Nb–CeO2/Cu catalysts obtained via sol–gel, coprecipitation, hydrothermal, and incipient wetness impregnation methods was performed against a normal configuration for hydrogen production through a water–gas shift reaction. Exposed oxygen-deficient Nb–CeO2 (111) facet sites deposited on Cu (111) facets with enhanced densities of Ce3+, Cu+, and Ov species for high reducibility were confirmed using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. Nb–CeO2/Cu catalyst prepared by coprecipitation exhibited the highest activity of 68 % CO conversion, 100 % H2 selectivity at 360 °C, and gas hourly space velocity of 43,535 h−1. The lowest activation energy (39.67 kJ/mol) and high turnover frequency illustrate facilitated water dissociation and CO oxidation in close vicinity across nanointerfaces. For the Nb–CeO2/Cu catalyst prepared by the coprecipitation method, nanosized Nb–CeO2 stabilized over the porous Cu support was optimum for generating interfaces and facilitating catalytic performance. It is to underscore that the catalyst prepared by coprecipitation exhibited constant H2 production under realistic conditions for 102 h, demonstrating the robust structural features of the configuration Nb–CeO2/Cu.

Katalitička aktivnost uzoraka pseudobemita impregnisanih različitim koncentracijama kobalta u oksidativnoj degradaciji tartrazina u prisustvu Oksona

Pseudoboehmite was impregnated with cobalt using a incipient wetness impregnation method. Two different concentrations of cobalt were used for impregnation: 3 mas% and 6 mas% of Co2+ relative to the mass of pseudoboehmite. The obtained materials were calcined at 500 ºC. The synthesized catalysts were tested in the process of oxidative degradation of tartrazine dye in the presence of Oxon as a source of sulfate anion radicals. The influence of temperature on the dye degradation efficiency was investigated. It was observed that the degradation rate increases with the increasing of temperature. The experimentally obtained results were tested using the most common kinetic models and it was found that the reaction follows a pseudo-first order rate in all cases. It was also observed that with an increase in the cobalt content, the efficiency of the catalyst increases. In order to determine which reactive oxidative species is dominant in the investigated process, tertiary buthalnol and ethanol was added to the reaction system. According to the experimental results sulfate anion radicals were found to be the dominant reactive species.

Synergistic effect of K and Zn on Fe-based catalysts for efficient CO2 hydrogenation.

Excessive emission of CO2 into the atmosphere has severely impacted the global ecological environment. Converting CO2 into valuable chemicals and fuels is of great significance for sustainable development. However, low activity and undesirable selectivity often result from the inherent inertness of CO2. Herein, K- or/and Zn-modified Fe-based catalysts were prepared by an incipient-wetness impregnation method for CO2 hydrogenation via a cascade reaction. The results indicate that K species exist as K2O while Zn species exist as ZnFe2O4. In the CO2 hydrogenation pathway, K2O facilitates the adsorption of CO2 and restrains the adsorption of H2, accelerating the transformation of CO2 into C2-C4 olefins rather than paraffins while Zn species promote the dispersion of Fe species, leading to improved activity. Synergistically, a K- and Zn-modified Fe-based catalyst (2Zn-10K-Fe/Al) shows excellent catalytic CO2 hydrogenation activity, achieving a CO2 conversion of 77% which is 1.8 times that (42%) of the unmodified Fe-based catalyst (Fe/Al). Our catalyst also shows a significantly promoted selectivity to C2-C4 olefins of 17% in comparison with the Fe/Al catalyst (0%). It is envisioned that such a binary effect of elements might contribute to the low-cost and industrial production of Fe-based catalysts for selective CO2 conversion.

Effect of Ni/Al-MCM-41 Impregnation Method on Catalytic Deoxygenation of Reutealis Trisperma Oil

Deoxygenation of Reutealis trisperma oil into green diesel has been carried out using Ni/Al-MCM-41 catalyst. The Ni/Al-MCM-41 catalyst was prepared using the wetness impregnation and incipient wetness impregnation methods, hereinafter referred to as Ni/Al-MCM-41 (WI) and Ni/Al-MCM-41 (IWI). XRD and FTIR analysis shows a characteristic of amorphous phase for solid Al-MCM-41 catalyst. FTIR pyridine was used to assess the impact of the NiO impregnation technique on Lewis acid and Brønsted acidity. The acidity test showed that the Ni/Al-MCM-41 (WI) catalyst had the highest total acidity 0,227 mmol/g. The catalytic activity of Ni/Al-MCM-41 catalyst was examined in deoxygenation reaction of Reutealis trisperma oil under inert conditions for 4 hours. In comparison to Ni/Al-MCM-41(IWI) and Al-MCM-41 catalysts, the Ni/Al-MCM-41(WI) catalyst produced better results in the deoxygenation reaction of Reutealis trisperma oil with a selectivity of hydrocarbon compounds (C11-18) of 100% and a degree of deoxygenation of 92.77%.

Effects of molybdenum addition to activated carbon supported Ni‐based catalysts for CO2 methanation

AbstractRecently, CO2 methanation has become a technique that aims to reduce anthropogenic CO2 emissions by converting CO2 captured from stationary and mobile sources and H2 produced from renewable sources into CH4. Due to their excellent performance‐to‐cost ratio, Ni‐based catalysts were frequently used in such conversions. The main drawbacks, however, are that Ni has the propensity to aggregate and deposit carbon during the high‐temperature reaction. These issues can be partially resolved by including a support (e.g., MOF, zeolite, activated carbon, etc.) and a second transition metal (e.g., Mo, Co, or Fe) in Ni‐based catalysts. Therefore, the activity of Ni‐based catalysts at low temperatures needs to be improved. In this study, a series of mesoporous activated carbon (AC) supported bimetallic Ni–Mo catalysts (Ni–xMo/AC, Ni = 13 wt.%, x = 5, 7, 9, 11 wt.%) were synthesized using the incipient wetness impregnation method. The effect of Mo content on the catalyst's activity was examined in a fixed‐bed reactor. At 250–650°C, 1‐atmosphere pressure, gas hourly space velocity (GHSV): 1200 mL h−1 g−1, and H2/CO2 ratio: 4:1, the catalytic efficiency of these catalysts was examined. The catalysts were analyzed using transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), X‐ray powder diffraction (XRD), N2‐physisorption, and scanning electron microscopy/energy dispersive X‐ray spectroscopy (SEM‐EDX). Ni–7%Mo/AC catalyst showed the lowest carbon deposition rate, superior stability, and the best activity. The addition of Mo can improve the heat resistance of the Ni/AC catalyst and the interaction between the metal nickel and the support, which prevents the sintering of the catalyst. © 2023 Society of Chemical Industry and John Wiley &amp; Sons, Ltd.

Carbon dioxide hydrogenation to value-added products using Cu-based catalytic materials

In this work, we report on the synthesis and evaluation of catalytic materials composed of copper/calcium oxide/alumina (Cu/CaO/Al2O3) for carbon dioxide conversion to value-added products. Catalytic materials were synthesized using sequential incipient wetness impregnation method. Synthesized materials with different compositions of copper and adsorbent were tested in a high-pressure packed bed reactor under a pressure P =60 bars, temperature T=300 °C, and hydrogen to carbon dioxide ratio (H2/CO2 = 3) to determine their performances and catalytic activities. The results of the activity revealed that CaO-based catalysts were very active in converting CO2 to methanol and carbon monoxide. Catalyst containing 30%Cu10%CaO achieved the highest CO2 conversion of 16.5% and a maximum methanol selectivity of 17.8%, while the lowest selectivity towards carbon monoxide (CO) were obtained using 20%Cu-containing catalyst. Reducing CaO content from 10wt% to 5wt% boosted the CO2 conversion to 18% with higher selectivity towards CO compared to the catalyst containing 10%CaO.

Broadening active temperature window for NH3-SCR on tungsten-promoted MnCeOx nanorod catalysts

xW/MnCe nanorod catalysts with various tungsten contents were synthesised using the incipient wetness impregnation method for selective catalytic reduction (SCR) of nitrogen oxides with NH3 (i.e. NH3-SCR reaction). Tungsten addition considerably widened the active temperature window and enhanced the SO2/H2O tolerance of the catalysts. The optimum catalytic performance was achieved when the tungsten content was 15 wt% with NOx conversion being ≥ 80% in the range of 175–450 °C. The MnCe nanorods approximately retained their morphology after tungsten loading. Microcrystalline WO3 formed when the W content was 15%, resulting in increments in the amount of Ce3+ and Mn4+, which is in favour of the NH3-SCR reaction on the catalyst surface. Moreover, the broad active temperature windows of the tungsten-modified MnCe nanorod catalysts were related to the balance between the redox and acidic properties. Tungsten addition enhanced the acidity of the MnCe catalyst while suppressing its reducibility. Both the Brønsted and Lewis acid sites are active, and the formation of reactive bridging nitrate species promote the performance of 15 W/MnCe catalyst. Overall, this study provided an easy method of adjusting the active temperature window of Mn–Ce nanorod catalysts through W modification.

Palladium-Containing Catalysts Based on Functionalized CNFs for the Dehydrogenation of Methylcyclohexane

The activity of palladium-containing catalysts based on functionalized carbon nanofibers prepared by an incipient wetness impregnation method in the dehydrogenation reaction of methylcyclohexane was investigated. Methylcyclohexane is considered as one of the most promising liquid hydrogen carriers. The dependence of the catalytic characteristics of the samples on the functionalization conditions of carbon nanofibers has been studied. By temperature-programmed desorption, it was shown that an increase in the treatment time of carbon nanofibers in concentrated nitric acid from 1 to 3 h increases the number of hydroxyl groups on their surface, and treatment for 6 h contributes to a rise in the concentration of carboxyl groups and their derivatives (esters and anhydrides). Additional calcination of the functionalized nanofibers in an inert atmosphere at 530°C yielded a sample containing predominantly hydroxyl groups. The presence of hydroxyl groups on the surface of the carbon material has a positive effect on the performance of the catalysts, while the presence of carboxyl groups leads to a decrease in the yield of toluene. It is assumed that the observed differences in catalyst activity are due to differences in dispersion and localization of palladium particles.