Monometallic Ones Research Articles

Molecular Dynamics Study of Bending Deformation of Mo2Ti2C3 and Ti4C3 (MXenes) Nanoribbons

We report a computational study of the bending deformation of two-dimensional nanoribbons by classical molecular dynamics methods. Two-dimensional double transition metal carbides, together with monometallic ones, belong to the family of novel nanomaterials, so-called MXenes. Recently, it was reported that within molecular dynamics simulations, Ti4C3 MXene nanoribbons demonstrated higher resistance to bending deformation than thinner Ti2C MXene and other two-dimensional materials, such as graphene and molybdenum disulfide. Here, we apply a similar method to that used in a previous study to investigate the behavior of Mo2Ti2C3 nanoribbon under bending deformation, in comparison to the Ti4C3 sample that has a similar structure. Our calculations show that Mo2Ti2C3 is characterized by higher bending rigidity at DTi2Mo2C3≈92.15 eV than monometallic Ti4C3 nanoribbon at DTi4C3≈72.01 eV, which has a similar thickness. Moreover, approximately the same magnitude of critical central deflection of the nanoribbon before fracture was observed for both Mo2Ti2C3 and Ti4C3 samples, wc≈1.7 nm, while Mo2Ti2C3 MXene is characterized by almost two times higher critical value of related external force.

In Situ Growth of Nanorod-Shaped Ni,Co-MOF on Mo2CTx MXene Surface to Realize Enhanced Energy Storage for Supercapacitors.

Mo2CTx MXene materials, known for their high conductivity and abundant surface functional groups, are widely utilized as electrode materials in supercapacitors. However, their tendency to stack during electrochemical energy storage hinders their performance. The in situ growth of nanorod-shaped Ni,Co bimetallic metal-organic frameworks (Ni,Co-MOF) on Mo2CTx MXene effectively mitigates this stacking. With their porous structure and high specific surface area, MOFs excel in energy storage, and bimetallic MOFs outperform monometallic ones. The synergy between Mo2CTx MXene and Ni,Co-MOF yields an outstanding performance. In a three-electrode system with 1 M KOH, the Mo2CTx/Ni,Co-MOF composite shows a specific capacitance of 58 mAh g-1 (56.26 mAh cm-3) at 1 A g-1. When used in a Mo2CTx/Ni,Co-MOF//AC asymmetric supercapacitor, it achieves an energy density of 22.7 Wh kg-1(0.022 Wh cm-3) at a power density of 293 W kg-1 (0.284 W cm-3). Future work will focus on enhancing synthesis methods, exploring different bimetallic combinations, and optimizing electrode designs for gas sensors, batteries, fuel cells, biological sensors, and so on, with outstanding performance and sustainability.

Towards improved stability of transition metal nitrides in aqueous solutions

Transition metal nitrides (TMNs), in some cases referred as metallic ceramics, have unique physical and chemical properties, thanks to their ceramic-metallic nature, and are considered an attractive alternative to noble metals for electrochemical processes. In particular, theoretical work predicts TMNs as promising electrocatalysts towards the nitrogen reduction reaction (NRR). However, recent experimental studies under realistic conditions, have shown the release of lattice nitride to ammonia in a noncatalytic process, suggesting inherent instability of these materials. TMNs stability can be increased by the incorporation of a second metal in the lattice, to form bimetallic systems. Herein, we present a robust approach to prepare nonprecious transition multi-metallic nitride nano-catalysts, followed by a comprehensive study on their stability. The stability of the as-prepared catalysts was tested in electrolytes relevant for electrocatalysis, showing a higher chemical resistance of the bimetallic catalysts over the monometallic ones. This study suggests a novel approach to matching electrolyte pH and catalyst to ensure chemical stability in the electrochemical environment.

Synthesis and Catalytic Performance of Bimetallic Oxide-Derived CuO-ZnO Electrocatalysts for CO2 Reduction.

Steering the selectivity of electrocatalysts toward the desired product is crucial in the electrochemical reduction of CO2. A promising approach is the electronic modification of the catalyst's active phase. In this work, we report on the electronic modification effects on CuO-ZnO-derived electrocatalysts synthesized via hydrothermal synthesis. Although the synthesis method yields spatially separated ZnO nanorods and distinct CuO particles, strong restructuring and intimate atomic mixing occur under the reaction conditions. This leads to interactions that have a profound effect on the catalytic performance. Specifically, all of the bimetallic electrodes outperformed the monometallic ones (ZnO and CuO) in terms of activity for CO production. Surprisingly, on the other hand, the presence of ZnO suppresses the formation of ethylene on Cu, while the presence of Cu improves CO production of ZnO. In situ X-ray absorption spectroscopy studies revealed that this catalytic effect is due to enhanced reducibility of ZnO by Cu and stabilization of cationic Cu species by the intimate contact with partially reduced ZnO. This suppresses ethylene formation while favoring the production of H2 and CO on Cu. These results show that using mixed metal oxides with different reducibilities is a promising approach to alter the electronic properties of electrocatalysts (via stabilization of cationic species), thereby tuning the electrocatalytic CO2 reduction reaction performance.

Roles of iron and manganese in bimetallic biochar composites for efficient persulfate activation and atrazine removal

As for Atrazine (C8H14ClN5) degradation in soil, iron (Fe)-manganese (Mn) bimetallic biochar composites were proved to be more efficient for persulfate (PS) activation than monometallic ones. The atrazine removal rates of Fe/Mn loaded biochar + PS systems were 2.17–2.89 times higher than Fe/Mn loaded biochar alone. Compared with monometallic biochar, the higher atrazine removal rates by bimetallic biochar (77.2–96.7%) were mainly attributed to the synergy degradation and adsorption due to the larger amounts of metal oxides on the biochar surface. Atrazine degradation in Fe-rich biochar systems was mainly attributed to free radicals (i.e., SO4·-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ ext{SO}}_{4}^{ \\cdot - }$$\\end{document} and ·OH) through oxidative routes, whereas surface-bound radicals, 1O2, and free radicals were responsible for the degradation of atrazine in Mn-rich biochar systems. Furthermore, with a higher ratio of Fe(II) and Mn(III) formed in Fe-rich bimetallic biochar, the valence state exchange between Fe and Mn contributed significantly to the more effective activation of PS and the generation of more free radicals. The pathways of atrazine degradation in the Fe-rich bimetallic biochar systems involved alkyl hydroxylation, alkyl oxidation, dealkylation, and dechlorohydroxylation. The results indicated that bimetallic biochar composites with more Fe and less Mn are more effective for the PS-based degradation of atrazine, which guides the ration design of easily available carbon materials targeted for the efficient remediation of various organic-polluted soil.Graphical

Ni-Cu and Ni-Co-Modified Fly Ash Zeolite Catalysts for Hydrodeoxygenation of Levulinic Acid to γ-Valerolactone.

Monometallic (Ni, Co, Cu) and bimetallic (Ni-Co, Ni-Cu) 10-20 wt.% metal containing catalysts supported on fly ash zeolite were prepared by post-synthesis impregnation method. The catalysts were characterized by X-ray powder diffraction, N2 physisorption, XPS and H2-TPR methods. Finely dispersed metal oxides and mixed oxides were detected after the decomposition of the impregnating salt on the relevant zeolite support. Via reduction intermetallic, NiCo and NiCu phases were identified in the bimetallic catalysts. The catalysts were studied in hydrodeoxygenation of lignocellulosic biomass-derived levulinic acid to γ-valerolactone (GVL) in a batch system by water as a solvent. Bimetallic, 10 wt.% Ni, and 10 wt.% Cu or Co containing fly ash zeolite catalysts showed higher catalytic activity than monometallic ones. Their selectivity to GVL reached 70-85% at about 100% conversion. The hydrogenation activity of catalysts was found to be stronger compared to their hydration ability; therefore, the reaction proceeds through formation of 4-hydroxy pentanoic acid as the only intermediate compound.

Cu/Ag bimetallic nanoparticles produced by cylindrical post-magnetron gas aggregation source – A novel galvanic corrosion-based antibacterial material

A novel strategy to produce bi-metallic heterogeneous Cu/Ag nanoparticles using the gas aggregation source based on cylindrical post-magnetron with segmental Cu/Ag targets is introduced and investigated. It is shown that the production rate of nanoparticles depends not only on the magnetron current and aggregation pressure but also on the ratio of the Cu and Ag in the segmental target. Enhanced production of nanoparticles for larger Cu part in the segmental target has been observed. Furthermore, it is demonstrated that various types of Cu/Ag nanoparticles may be produced including dumbbell-like or onion-like ones with well-separated Cu and Ag domains. Finally, it has been for the first time confirmed that the gas-phase synthesized heterogeneous Cu/Ag nanoparticles are prone to extensive galvanic corrosion. This effect promotes the antibacterial efficiency of Cu/Ag nanoparticles compared to mono-metallic Cu ones, making such nanoparticles highly interesting for medical applications.

Realization of high-pressure dry methane reforming by suppressing coke deposition with Co-Rh intermetallic clusters

It is economical to perform methane and carbon dioxide reforming under high-pressure and temperature conditions, but the harsh operation condition poses a grand challenge for coke-resistant catalyst design. We report herein that surface-segregation-free Co1Rh3 clusters are stable catalysts under 20 bars at 850 oC. Microkinetic analysis discloses that balanced and lowered surface coverages of C* and O* constitute the most abundant reaction intermediates on Co1Rh3 clusters at elevated pressures, with respect to that of the monometallic ones, thus avoiding surface carbon accumulation or surface oxidative deactivation. Moreover, density functional theory calculations of carbon atom nucleation discloses that adsorbed carbon transformation to refractory, graphene-like carbon is suppressed on Co1Rh3 cluster surface, owing to increased energetic barrier and ensemble size, hence, only CO2 gasifiable soft carbon could form. The revelation of the electronic/geometric features of Co1Rh3 is regarded to provide a guidance for future coke-resistant catalyst design.

Mono- and Bimetallic Aluminum Complexes Supported by Thioether-Amide Ligands: Synthesis, Characterization, and Application in the Ring Opening Polymerization of l-Lactide

Mono- and bimetallic aluminum complexes bearing bidentate NS or tetradentate NSSN ligands have been synthesized via reaction of AlMe3 with the corresponding proligand and spectroscopically characterized. In these complexes the aluminum centers are surrounded by anionic nitrogen and neutral sulfur atoms that, together with the carbon atoms of the alkyl groups, produce tetrahedral coordination geometries. In the bimetallic complexes the two metal centers are linked by a thioether-bridge of different lengths. The solid state structure of the complexes featuring the thioethyl or thiopropyl bridge were determined by X-ray diffraction studies. Both mono- and bimetallic aluminum complexes display fluxional behaviors in solution. After proper activation, all complexes were able to promote the ring opening polymerization of l-lactide in toluene solution. The polymerizations were well controlled as testified by the linear increase of the molecular weights with the conversions and the narrow polydispersity indexes. The highest activity was observed for the bimetallic complex bearing the NSSN ligand with the shortest bridge (ethyl bridge) with a turnover frequency of 11.6 molLA·molAl–1·h–1 (toluene, 80 °C). The activity decreased as the distance between the two metal centers increased. Moreover, the activity of the bimetallic complex with the ethyl bridge was higher than those of the monometallic ones. These findings suggest that a cooperative interaction between two aluminum centers is operative in the bimetallic complex with the shortest bridge.

Study on the Structure vs Activity of Designed Non-Precious Metal electrocatalysts for CO2 Conversion

This work investigates Cu and Cu-Sn nanocatalysts with controlled composition and morphology for the electrochemical CO2 reduction reaction to value-added chemicals, showing that bimetallic materials possess active sites with increased specific activity toward activation and reduction of CO2 compared to monometallic ones. While Cu showed high selectivity for the competitive hydrogen evolution reaction, bimetallic Cu-Sn electrocatalysts were selective towards CO and formates. Nanoparticles were prepared via a straightforward chemical process, leading to small, well-define and crystalline nanoparticles, either mono or bimetallic, where Cu and Sn precursors are blended in one step to achieve alloyed or core–shell structures.

Synthesis of glycine-mediated CuO–Fe2O3–MgO nanocomposites: Structural, optical, and antibacterial properties

Multi-phase metal oxides nanocomposites (NCs) have attracted considerable attention due to their extraordinary properties and novel applications over monometallic ones. Hence, trimetallic oxides nanoparticles (NPs) are preferred because of their immensely improved optical, catalytic, and biological properties, but few materials have been reported. Besides, glycine is an excellent structure-directing agent for NPs production with tailored physicochemical properties. Thus, in this work, a novel tri-phase CuO–Fe2O3–MgO (1:1:1) NCs was prepared via a sol-gel method in the presence of glycine as a fuel. The obtained NCs were characterized by Fourier transmission infrared, X-ray diffraction (XRD), Scanning electron micrographs, and UV-Vis. The XRD analysis emphasized the formation of NCs with monoclinic CuO, cubic MgO, hexagonal Fe2O3, and tetragonal CuFe2O4 crystals. The average crystallite size (D) was in the order of 10th of nm as computed by Scherrer method, with ternary phase seemingly affect the straightforward influence of glycine fuel concentration on the final crystallite sizes. UV-Vis analysis indicates two optical energy bandgaps which increased as glycine concentration increase. The antibacterial test against Staphylococcus aureus and Escherichia coli bacteria revealed comparable activity to that of Azithromycin standard drug, which increased with glycine concentration increase. The glycine-based tailored structural, optical, and biological properties of such trimetallic NCs making them of considerable candidate for certain applications development, possibly electronics and antibiotics; a case that encourage further investigations.

Bimetallic PdFe catalysts in hydrodechlorination of diclofenac: Influence of support nature, metal deposition sequence and reduction condition

Monometallic palladium and bimetallic palladium-iron catalysts (1 wt% Pd, 10 wt% Fe) were prepared by sequential (denoted as “-s”) and co- (denoted as “-c“) impregnation of alumina and silica – zirconia (ZS) supports with metal nitrates. After reduction with H2 at 320 and 30 °C the catalysts were tested in hydrodechlorination of diclofenac in water at 30 °C in batch and flow-type reactors. The alumina-supported catalysts were more active than the ZS-supported ones, while the bimetallic catalysts were more efficient than the monometallic Pd ones. The co-impregnated bimetallic catalysts showed higher efficiencies than the catalysts prepared by the sequential deposition of metals. Pd/Al2O3 and PdFe/Al2O3-c provided the same rate of DCF conversion in the batch reactor after both types of preliminary reduction, opening the way for energy saving. The catalysts were studied by XRD, TEM, SEM-EDX, low-temperature N2 physisorption, Mössbauer spectroscopy, DRIFT-CO and by XPS after in situ reduction at 320 °C and ex-situ reduction at 30 °C. The improvements in catalyst efficiency resulted from wider pores, formation of PdFe alloys or Pd-Fe-Ox species on the surface, high Pd0/Pd2+ ratio, low extent of Pd encapsulation with the support and especially its coordinately unsaturated sites. The encapsulation degree was the lowest in the co-impregnated catalysts.

Evolution of hollow dodecahedron carbon coated FeCo with enhance of electromagnetic properties

FeCo@C with a hollow porous dodecahedron structure was obtained through carbonization of ZIF-67 etched with Fe3+. During the pyrolysis process, the organic skeleton of the ZIF-67 was carbonized, forming graphitic carbon and carbon nanotubes. The etching effect of Fe3+ with different concentrations on the morphology of ZIF-67 is studied. The MOF-derived porous carbon bimetallic nanocomposites exhibited stronger electromagnetic wave absorption performance than the monometallic ones. Specifically, the optimized sample has a reflection loss of −70.69 dB at 11.28 GHz, as the thickness is 2.07 mm. The enhanced electromagnetic wave (EMW) absorption performance of the nanocomposites can be attributed to the multiple interfaces and capacitive structure formed by catalytically produced carbon nanotubes. This achievement could be used as a reference for the development of MOF-derived porous carbon nanocomposite EMW absorbers.

Active Ni and Fe species on catalysts Ni/Al2O3 and NiFe/Al2O3 for the oxidative dehydrogenation (ODH) of ethane to ethylene assisted by CO2

Ni/Al2O3 and NiFe/Al2O3 catalysts were synthesized by incipient wetness impregnation and tested for oxidative dehydrogenation (ODH) of ethane to ethylene. The effect of Ni loading and Fe as a promoter for bimetallic catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), and temperature-programmed reduction (H2-TPR). The catalyst with 10 wt% Ni and 6.6 wt% Fe (NiFe32) displayed the highest ODH activity. XRD results showed smaller crystalline NiO (˂ 7 nm) for bimetallic catalysts than the monometallic ones. Raman results depicted NiOx species in the monometallic catalysts. The bimetallic catalysts exhibited spinel-type structures as NiFe2O4 and FeAl2O4 related to more active species in ODH of ethane. DRS results revealed that the higher ODH activity for bimetallic catalysts is related to a predominance of Ni and Fe in tetrahedral symmetry (Td) than octahedral symmetry (Oh). These suggest that tetrahedral symmetry species were more effective than octahedral symmetry. TPR profiles showed that the iron addition increased the nickel species with strong interaction with the support. This rearrangement of Ni and Fe species in octahedral and tetrahedral sites of the NiO and alumina lattice could explain the shift reduction temperatures for Ni species and the formation of the spinel-type structure in the bimetallic catalysts. A relation between the metal-support interaction and the selectivity toward ethylene was found. A higher strong metal-support interaction favors a better catalytic activity.

Catalytic Decomposition of Methane to Hydrogen over Al2O3 Supported Mono- and Bimetallic Catalysts

This article discusses the decomposition of methane in the temperature range 550–800 °C on low-percentage monometallic (Ni/g-Al2O3, Co/g-Al2O3) and bimetallic (Ni-Co/g-Al2O3) catalysts. It is shown that the bimetallic catalyst is more active in the decomposition of methane to hydrogen than monometallic ones. At a reaction temperature of 600 °C, the highest methane conversion is 81%, and the highest hydrogen yield of 51% is formed on Ni-Co/g-Al2O3. A complex of physicochemical methods (Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Temperature Programmed Reduction (TPR-H2), etc.) established that the addition of cobalt oxide to the composition of Ni/g-Al2O3 leads to the formation of surface bimetallic Ni-Co alloys, while the dispersion of particles increases and the reducibility of the catalyst is facilitated, which provides an increase in the concentration of metal particles - active centers, which can be the reason for an increase in the catalytic properties of a bimetallic catalyst in comparison with monometallic ones. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Bimetallic Co-Rh Systems as a Prospective Base for Design of CH4 Reforming Catalysts to Produce Syngas with a Controllable Composition

Dry and bireforming (CO2-H2O) of methane are the most environmentally friendly routes involving two main greenhouse gases to produce syngas—an important building block for large-scale production of various commodity chemicals. The main drawback preventing their industrial application is the coke formation. Developing catalysts that do not favour or are resistant to coke formation is the only way to improve the catalyst stability. Designing an economically viable catalyst may be achieved by exploiting the synergic effects of combining noble (expensive but coke-resistant) and non-noble (cheap but prone to carbonisation) metals to form highly effective catalysts. This work deals with development of highly active and stable bimetallic Co-containing catalysts modified with small amount of Rh, 0.1–0.5 mass %. The catalysts were characterised by BET, XRD, TEM, SEM, XPS, and TPR-H2 methods and tested in dry, bi-, and for comparison in steam reforming of methane. It was revealed that the bimetallic Co-Rh systems is much more effective than monometallic ones due to Co-Rh interaction accompanied with increasing dispersion and reducibility of Co. The extents of CH4 and CO2 conversion over the 5%Co-Rh/Al2O3 are varied within 85–99%. Syngas with variable H2/CO = 0.9–3.9 was formed. No loss of activity was observed for 100 h of long-term stability test.

Construction of CdSe-AuPd quantum dot 0D/0D hybrid photocatalysts: charge transfer dynamic study with electrochemical analysis for improved photocatalytic activity.

The integration of semiconductor quantum dots and noble metal nanoparticles can efficiently couple numerous effects corresponding to the individual domains of the hybrid system for a variety of applications. Herein, we establish a direct correlation between the electronic band structure and optical band gap of monometallic and bimetallic alloy nanoparticle decorated CdSe quantum dots, which in turn regulate the charge shuttling dynamics in a quantum dot hybrid (QDH) system. Directly coupled Au, Pd, AuPd, and CdSe QDHs were prepared via a simple fabrication technique. The photoluminescence intensity of the QDHs was quenched compared to that of CdSe quantum dots with a maximumally diminished CdSe-AuPd system. Broadening of the absorbance peak along with a blue shift for QDHs confirm the interaction of the energy levels of the QDs and metal domains. AuPd decorated CdSe QDs demonstrate enhanced photocatalytic activity compared to their monometallic counterparts, which has made them interesting catalysts reported for the first time. Lifetime decay measurements, which isolated the individual charge-transfer steps, showed that a maximum amount of photoexcitons can be separated by bimetallic alloy decoration compared to monometallic ones. Cyclic voltammetry results offer insight into the change in the conduction band edge energy position for both monometallic and bimetallic incorporating semiconductor hybrid systems. Our findings reveal that photoexcited semiconductor quantum dots undergo charge equilibration when the QDs are in contact with metallic domains, influencing the shifting of the conduction band energy level of the hybrid to a more negative potential, and this is a maximum for the CdSe-AuPd hybrid, resulting in the best photocatalytic activity. Shuttling of electrons around the conduction band of CdSe and the Fermi level of the metallic domains is the main deciding factor for an efficient photocatalyst hybrid system.

Hydrothermal ion exchange synthesis of CoM(M=Fe or Mn)/MXene 2D/2D hierarchal architectures for enhanced energy storage

Bimetallic compounds can offer higher electrochemical activity and capacity than monometallic ones owing to their rich chemical valences. Herein, the performance enhancement of monometallic compounds by introducing metal ions was demonstrated, and the effects of different metal ions were investigated. Through introduction of metal ions into LDHs under a hydrothermal environment, one kind of 2D/2D hierarchical CoM-LDH(M=Fe or Mn)/MXene composites were successfully synthesized. It was found that the introduced Fe ions extremely improves the specific capacity and the introduced Mn ions extremely enhances the rate capability of monometallic composite. The fabricated CoFe-LDH/MXene (CF-MX10) electrode exhibits a specific capacity of 808 F g−1 at current density of 0.5 A g−1, much higher than that of CoMn-LDH/MXene (CM-MX10, 562 F g−1) and Co(OH)2/MXene (C-MX10, 270 F g−1). The high areal capacity or rate capacity are attributed to strong synergistic effect between CoM-LDH and MXene, as well as the introduction of metal ions that change the architecture and the electronic or ionic conductivity, which leads to much improved electrical conductivity and electrochemical stability.

Comparison of bimetallic Co-Ru nanoparticles supported on highly porous activated carbonized polyacrylonitrile with monometallic ones in ethanol steam reforming

A method for simultaneous formation of mono- (Co, Ru) or bimetallic (Co-Ru) nanoparticles and a highly porous carbon support is proposed. The obtained IR-PAN-Co, IR-PAN-Ru and IR-PAN-Co-Ru samples based on pyrolyzed polyacrylonitrile are characterized by a specific surface area within the range of 1683–2174 m2 g-1, which strongly depends on the nature of the metal used. It has been shown that the presence of cobalt leads to the graphitization of amorphous carbon and the formation of carbon shells around the mono- and bimetallic nanoparticles. The average size of metallic nanoparticles for all three samples ranged within 12–20 nm. The comparison of the samples revealed a dramatic advantage of the bimetallic catalyst in the ethanol steam reforming (ESR). The IR-PAN-Co-Ru sample has shown the highest hydrogen yield, which was 5.6 moles per mole of EtOH at 550 °C. To evaluate the stability of the catalysts, the catalytic test was carried out for 17 h after which no deactivation of the catalysts was observed. The spent catalysts were characterized by the same techniques as the as-prepared ones. It was found that there are no significant changes in the structure of the catalysts after the ESR reaction. The presence of filamentous carbon in the spent cobalt-based catalysts has been observed, which does not lead to deactivation in the time period studied.

Improving noble metal catalytic activity in the dry reforming of methane by adding niobium

This work describes the use of Pd-Nb catalysts supported on commercial silica in the dry reforming of methane. The effect of Pd/Nb ratio was evaluated and it determined the catalytic response of the prepared catalysts. Thus, it was observed that the catalytic activity increased with the Pd/Nb ratio and bimetallic samples were more active than the monometallic ones. The sample with the highest Pd/Nb ratio was the best in terms of conversion, selectivity and stability. Nb presence decreased the amount of carbon deposited on the catalysts since the decomposition of CH4 is minimised in the operating conditions.