Single Metal Catalysts Research Articles

Single Metal Atom Photocatalysis

AbstractPhotocatalysis suffers from rapid recombination of photoexcited charge carriers and limited active sites for the catalytic reactions, resulting in unsatisfactory performances that are far from practical application. Single metal atom catalysts not only increase the number of active sites due to the maximum atom‐utilization efficiency, but also enhance the intrinsic activity of each active site because of their unique geometric and electronic features. Furthermore, single metal atom catalysts provide a platform for photocatalysis research on the atomic level. This review discusses the unique characteristics, including geometric and electronic properties, of single metal atom catalysts, summarizes their synthesis strategies, and reviews their most recent development in photocatalysis. Finally, the challenges of single metal catalysts for both fundamental research and practical application are highlighted.

A DFT study on the possibility of using a single Cu atom incorporated nitrogen‐doped graphene as a promising and highly active catalyst for oxidation of CO

AbstractUsing dispersion‐corrected density functional theory (DFT) calculations, a single Cu adatom incorporated nitrogen‐doped graphene (CuN3‐Gr) is proposed as a new and highly active noble‐metal‐free catalyst for carbon monoxide (CO) oxidation reaction. According to our results, the Cu adatom can be stably anchored onto the monovavancy site of the nitrogen‐doped graphene, and the resulting large diffusion barrier suggests that the metal clustering is avoided in CuN3‐Gr. Three possible reaction mechanisms for CO oxidation (ie, Eley–Rideal, Langmuir–Hinshelwood, and termolecular Eley–Rideal) are systematically studied. It is found that the activation energy for the rate‐determining step of the termolecular Eley–Rideal mechanism is only 0.13 eV, which is much smaller than those of others. The results of this study may provide a useful guideline for the design of highly active and promising single‐metal catalysts for the CO oxidation reaction based on graphene.

Asymmetric remote C-H borylation of internal alkenes via alkene isomerization

Recent years have witnessed the growing interest in the remote functionalization of alkenes for it offers a strategy to activate the challenging C–H bonds distant from the initiation point via alkene isomerization/functionalization. However, the catalytic enantioselective isomerization/functionalization with one single transition metal catalyst remains rare. Here we report a highly regio- and enantioselective cobalt-catalyzed remote C–H bond borylation of internal alkenes via sequential alkene isomerization/hydroboration. A chiral ligand featured twisted pincer, anionic, and non-rigid characters is designed and used for this transformation. This methodology, which is operationally simple using low catalyst loading without additional activator, shows excellent enantioselectivity and can be used to convert various internal alkenes with regio- and stereoisomers to valuable chiral secondary organoboronates with good functional group tolerance.

Exploring different reaction mechanisms for oxidation of CO over a single Pd atom incorporated nitrogen-doped graphene: A DFT study

Single-metal catalysts have attracted particular interests in recent years due to their outstanding catalytic activity in CO oxidation reaction. In the present study, periodic DFT calculations are performed to investigate possible reaction mechanisms for oxidation of CO over a single Pd atom incorporated nitrogen-doped graphene. According to our results, the formation energy of a single-vacancy decreases by incorporation of pyridinic nitrogen atoms in graphene. The Pd atom can be stably anchored over the vacancy site, as evidenced by the large energy barriers for diffusion of the Pd atom to its neighboring sites. It is found that the incorporation of nitrogen atoms makes a significant increase in the adsorption energy of O2 and CO molecules over the supported Pd atom. The latter can be attributed to the shift in the bonding states of the Pd towards the Fermi level, which facilitates the charge-transfer from the 4d orbitals of this atom to the 2π∗ orbitals of O2 and CO molecules. The CO oxidation over the Pd atom supported nitrogen-doped graphene can proceed via three different mechanisms; namely, Eley-Rideal (ER), Langmuir-Hinshelwood (LH) and termolecular Eley-Rideal (TER) mechanisms. Our calculations reveal that the TER mechanism is preferred over the LH and ER, due to its smaller activation energy. The CO oxidation via the TER mechanism is a thermodynamically favorable process over the supported Pd atom, due to a large negative change in the Gibbs free energy of this reaction. The findings of this study can be useful to design more efficient single-atom catalysts to remove toxic CO molecules.

Cover Feature: Graphene Supported Single Atom Transition Metal Catalysts for Methane Activation (ChemCatChem 15/2018)

Cover Feature: Graphene Supported Single Atom Transition Metal Catalysts for Methane Activation (ChemCatChem 15/2018)

Electrocatalyst Performance for Selective Methanol Formation in Methane Electrolyzer

Methane’s abundance and low cost makes it an optimal raw material for chemical precursors and other energy dense fuels. Traditional methods of converting methane to methanol require large amounts of energy through thermal catalysis and high capital costs. However, electrochemical oxidation of methane is a cleaner and cheaper way to produce methanol, and a systematic study of an electrochemical cell could help assure selectivity over undesired products. Electrochemical oxidation of methane is an underdeveloped field, but electrochemical cells have been employed with high selectivity towards methanol.[1,2] Promising transition state metal-oxide catalysts have shown activity towards the selectivity of methanol over other by products, such as carbon dioxide, carbon monoxide, formic acid, formaldehyde.[2, 3] Further investigation of single site metal oxide catalysts is required to improve conversion and activity, but system optimization is also required. Reports of electrolyzer and fuel cell systems show varying assemblies, ranging from various solid and liquid electrolytes, temperatures, pressures, and current densities. [1-3] Few reports have been consistent on the operating current density and potential windows of such systems. Little work has been done on understanding how various components for these systems and understanding the phenomena of creating methanol in this partial oxidation pathway. In this study, we explore the activity, selectivity, efficiency of transition metal oxide catalyst in operation in an electrolyzer. The electrolyzer used was tested under a variety of relative humidity, operating temperatures, current densities, and membrane electrode assemblies. Through electrochemical and conductivity measurements, and gas phase analysis of the effluent, a better understanding of the partial electrochemical oxidation of methane to methanol is elucidated. The results of this study provide a systematic approach to this challenging problem and provide insights on new catalyst and electrochemistry pathways.

Graphene Supported Single Atom Transition Metal Catalysts for Methane Activation

AbstractSingle‐atom catalysis is a relatively new concept to enhance catalytic activity of transition metal atoms through proper choice of support. The interest in such systems is due to the fact that both the quantum size effect and support‐catalyst interactions may lead to unique electronic structures that may enhance catalytic properties. This allows for the design of materials systems at the atomic scale, tailored for specific reactions. Utilizing this concept, we investigated theoretically free and graphene supported single transition metal (TM) Cr, Mn, Fe, Co, and Cu atoms for activation of methane and identified catalytically active centers through C−H bond cleavage. We employed here dispersion corrected density functional theory taking into account the generalized gradient approximation and exchange correlations. The results indicate that graphene supported TM systems display relatively low activation barriers for both TM‐adsorbed and embedded types of graphene supports compared to that of free TM‐methane systems. The reaction pathway for graphene‐supported systems is characterized by a single spin state thereby eliminating a multi‐state reactivity as observed for free TM‐methane systems. Our findings show that the interaction of three d‐orbitals (dxz, dyz and d ) with methane, their relative position, and occupancy play a key role in governing the catalytic activity of supported TM systems.

O-, N-Atoms-Coordinated Mn Cofactors within a Graphene Framework as Bioinspired Oxygen Reduction Reaction Electrocatalysts.

Manganese (Mn) is generally regarded as not being sufficiently active for the oxygen reduction reaction (ORR) compared to other transition metals such as Fe and Co. However, in biology, manganese-containing enzymes can catalyze oxygen-evolving reactions efficiently with a relative low onset potential. Here, atomically dispersed O and N atoms coordinated Mn active sites are incorporated within graphene frameworks to emulate both the structure and function of Mn cofactors in heme-copper oxidases superfamily. Unlike previous single-metal catalysts with general M-N-C structures, here, it is proved that a coordinated O atom can also play a significant role in tuning the intrinsic catalytic activities of transition metals. The biomimetic electrocatalyst exhibits superior performance for the ORR and zinc-air batteries under alkaline conditions, which is even better than that of commercial Pt/C. The excellent performance can be ascribed to the abundant atomically dispersed Mn cofactors in the graphene frameworks, confirmed by various characterization methods. Theoretical calculations reveal that the intrinsic catalytic activity of metal Mn can be significantly improved via changing local geometry of nearest coordinated O and N atoms. Especially, graphene frameworks containing the Mn-N3 O1 cofactor demonstrate the fastest ORR kinetics due to the tuning of the d electronic states to a reasonable state.

Study on the formation of graphene by ion implantation on Cu, Ni and CuNi alloy

This study identifies the details for direct synthesis of graphene by carbon ion implantation on Cu, Ni and CuNi alloy. Firstly, diffusion and concentration of carbon atoms in Cu and Ni are estimated separately. The concentrations of carbon atoms near the surfaces of Cu and Ni after carbon ion implantation and subsequent thermal annealing were correlated with the number of atoms and with the coverage or thickness of graphene. Systematic experiments showed that the Cu has higher carbon diffusivity and graphene coverage than Ni but higher temperatures and longer annealing times are required to synthesize graphene, similar to those in chemical vapor deposition method. The CuNi system shows better graphene coverage and quality than that on a single metal catalyst even after a short annealing time, as it has larger carbon diffusivity and lower carbon solubility than Ni and shows lower activation energy than Cu.

Preparation of MnCo/MCM-41 catalysts with high performance for chlorobenzene combustion

MCM-41 was synthesized by a soft template technique. The specific surface area and pore volume of the MCM-41 were 805.9 m2/g and 0.795 cm3/g, respectively. MCM-41-supported manganese and cobalt oxide catalysts were prepared by an impregnation method. The energy dispersive X-ray spectroscopy clearly confirmed the existence of Mn, Co, and O, which indicated the successful loading of the active components on the surface of MCM-41. The structure and function of the catalysts were changed by modulating the molar ratio of manganese to cobalt. The 10%MnCo(6:1)/MCM-41 (Mn/Co molar ratio is 6:1) catalyst displayed the best catalytic activity according to the activity evaluation experiments, and chlorobenzene (1000 ppm) was totally decomposed at 270 °C. The high activity correlated with a high dispersion of the oxides and was attributed to the exposure of more active sites, which was demonstrated by X-ray diffraction and high-resolution transmission electron microscopy. The strong interactions between MnO2, Co3O4, MnCoOx, and MCM-41 indicated that cobalt promoted the redox cycles of the manganese system. The bimetal-oxide-based catalyst showed better catalytic activity than that of the single metal oxide catalysts, which was further confirmed by H2 temperature-programmed reduction. Chlorobenzene temperature-programmed desorption results showed that 10%MnCo(6:1)/MCM-41 had higher adsorption strength for chlorobenzene than that of single metal catalysts. And stronger adsorption was beneficial for combustion of chlorobenzene. Furthermore, 10%MnCo(6:1)/MCM-41 was not deactivated during a continuous reaction for 1000 h at 260 °C and displayed good resistance to water and benzene, which indicated that the catalyst could be used in a wide range of applications.

A versatile MOF-based trap for heavy metal ion capture and dispersion

Current technologies for removing heavy metal ions are typically metal ion specific. Herein we report the development of a broad-spectrum heavy metal ion trap by incorporation of ethylenediaminetetraacetic acid into a robust metal-organic framework. The capture experiments for a total of 22 heavy metal ions, covering hard, soft, and borderline Lewis metal ions, show that the trap is very effective, with removal efficiencies of >99% for single-component adsorption, multi-component adsorption, or in breakthrough processes. The material can also serve as a host for metal ion loading with arbitrary selections of metal ion amounts/types with a controllable uptake ratio to prepare well-dispersed single or multiple metal catalysts. This is supported by the excellent performance of the prepared Pd2+-loaded composite toward the Suzuki coupling reaction. This work proposes a versatile heavy metal ion trap that may find applications in the fields of separation and catalysis.

Defects and Interfaces on PtPb Nanoplates Boost Fuel Cell Electrocatalysis.

Nanostructured Pt is the most efficient single-metal catalyst for fuel cell technology. Great efforts have been devoted to optimizing the Pt-based alloy nanocrystals with desired structure, composition, and shape for boosting the electrocatalytic activity. However, these well-known controls still show the limited ability in maximizing the Pt utilization efficiency for achieving more efficient fuel cell catalysis. Herein, a new strategy for maximizing the fuel cell catalysis by controlling/tuning the defects and interfaces of PtPb nanoplates using ion irradiation technique is reported. The defects and interfaces on PtPb nanoplates, controlled by the fluence of incident C+ ions, make them exhibit the volcano-like electrocatalytic activity for methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), and oxygen reduction reaction (ORR) as a function of ion irradiation fluence. The optimized PtPb nanoplates with the mixed structure of dislocations, subgrain boundaries, and small amorphous domains are the most active for MOR, EOR, and ORR. They can also maintain high catalytic stability in acid solution. This work highlights the impact and significance of inducing/controlling the defects and interfaces on Pt-based nanocrystals toward maximizing the catalytic performance by advanced ion irradiation strategy.

Bimetallic Catalytic Systems Based on Sb, Ge and Ti for the Synthesis of Poly(ethylene terephthalate-co-isosorbide terephthalate).

The insertion of rigid monomers such as isosorbide into poly(ethylene terephthalate) (PET) allows for the access of polymers with improved properties, notably in terms of thermal stability. This biobased monomer is however poorly reactive, and harsh reaction conditions lead to color concerns regarding the resulting polymer. This has motivated the development of catalytic systems enabling an increase of the reaction rate and a good coloration. In this study, we have assessed bimetallic catalytic systems based on the main metals used for PET catalysis, i.e., antimony, germanium and titanium, for the synthesis of poly(ethylene terephthalate-co-isosorbide terephthalate) (PEIT). The Sb2O3/Ti(OiPr)4 combination leads to a high reaction rate while maintaining an acceptable coloration. On the other hand, combining Sb2O3 with GeO2 affords the formation of poly(ethylene terephthalate-co-isosorbide terephthalate) without coloration concerns and a reaction rate higher than that observed using the single metal catalysts. Molecular weights and microstructure including diethyleneglycol (DEG) and isosorbide contents are also discussed, together with the thermal properties of the resulting PEIT. The GeO2/Ti(OiPr)4 is also assessed, and leads to average performances.

Carbon Based Atomic Catalysts for Carbon Dioxide Reduction

Technological development and human mobility depends heavily on fossil-fuel-based energy infrastructure. The byproduct of this is a surplus generation of carbon dioxide (CO2) which causes major environmental challenges, and addressing this problem is technologically challenging. The mitigation of CO2 emissions involve separation, capture and sequestration of a significant fraction of the billion tons of CO2 currently produced worldwide each year. A more promising and direct alternative is a chemically recycling process that converts CO2 to carbon-neutral fuels or commodity chemicals employing water as the hydrogen source via electrochemical catalysis. This technology not only reduces greenhouse gases but also provides pathways to sustainable energy. The chemical reduction of CO2 is a complicated process involving multiple proton coupled electron transfer, theoretically resulting in a variety of products (e.g. CO, HCOOH, CH3OH, C2H4 and C2H5OH). Therefore the major challenge in CO2 reduction lies in the manipulation of the selectivity towards a specific product as demanded. However, the study on CO2 reduction has not substantially advanced primarily because of the lack of fundamental understanding of the reaction mechanism and the challenge of discovering efficient and robust catalysts for the various multi-electron transfer processes. Researchers have screened a wide range of materials for electrochemical reduction of CO2, including metals, alloys, organometallics, layered materials and carbon nanostructures, only copper (Cu) exhibits selectivity towards formation of multi-carbon hydrocarbons and oxygenates at fairly high efficiencies while most others favor production of carbon monoxide or formate. However, Cu suffers from the poor selectivity and large overpotential in the reactions. Compared to traditional metal nanoparticle catalysts, sub-nanometer and single atom metal catalysts (atomic catalysts) possess enhanced catalytic activity. Beyond metal-based atomic catalysts, we have recently shown metal free atomic catalysts of nitrogen (N) doped carbon sp2 sheets (graphene) as possible CO2 reduction catalysts. We designed N-incorporated carbon nanostructures (N-doped carbon nanotubes and N-doped graphene) for selective and efficient electro-reduction of CO2 into CO with high efficiency (~80%) and at low overpotential.1-3 We further demonstrated that the N-doped carbon materials can be atomically engineered to achieve the yield of high order (C2 and C3) products. when enriching the N-doping at the edge of carbon nanostructures, the N-doped graphene quantum dots (NGQDs, thickness ~ 1nm and diameter ~ 2 nm) exhibit exceptional activity towards formation of C2 products (C2H4 and C2H5OH) with high Faradaic efficiency of 40%, and the current density is enhanced to the order of magnitude of 100 mA/cm2 at this potentialOc.4 This is for the first time the metal-free electrocatalyst has been discovered to steer the CO2reduction to produce C2 hydrocarbons and oxygenantes at a relatively high yield comparable to those obtained with copper nanoparticle-based electrocatalysts.

Nanostructured Catalysts Synthesized by High-Energy Mechanical Alloying for Formic Acid Electrochemical Oxidation

Formic acid (FA) oxidation at Pd-X (where, X is cobalt or nickel) nanostructures synthesized by high-energy mechanical alloying (MA) was reported. The structure and morphology of Pd-X were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that Pd-Co was comprised mainly by the intermetallic Pd2Co formation while Pd-Ni by the alloy Ni0.525Pd0.475. Both catalysts exhibit lamellar agglomerates that were nanostructurated in nature (with crystallite sizes between 2 and 17 nm). The electrochemically active surface area of both catalysts was determined by CO stripping and the electrochemical results (cyclic voltammetry and chronoamperometry) demonstrated that Pd-Co and Pd-Ni displayed adequate catalytic activity towards FA oxidation reaction comparable to other systems reported in the literature including single metal, bimetallic, and trimetallic catalysts synthesized and supported differently.

Atomically dispersed Pd catalysts in graphyne nanopore: formation and reactivity

The formation of single-atom noble metal catalysts on carbon materials remains a challenge due to the weak interaction between metals and pristine carbon. By means of density functional theory (DFT) calculations, it is found that the atomically dispersed Pd in graphyne nanopore is much more stable than that of relative Pd clusters. The large diffusion barrier of Pd from the most stable hollow site to the bridge site confirms the kinetic stability of such structures. While CO adsorption causes the pulling of Pd from graphyne nanopore due to the low diffusion barrier, based on DFT calculations, which can be further confirmed by ab initio molecular dynamic simulations. Finally, CO oxidation on the reconstruction of Pd@graphyne exhibits an energy barrier of 0.62 eV in the rate-limiting step through the Langmuir–Hinshelwood mechanism. After the reaction, the catalyst can be restored to the original atomically dispersed state again. This study shows graphyne is an excellent support for an atomically dispersed or single-metal catalyst.

Bimetallic Pt–Au nanocatalysts electrochemically deposited on boron-doped diamond electrodes for nonenzymatic glucose detection

The enormous demand for medical diagnostics has encouraged the fabrication of high- performance sensing platforms for the detection of glucose. Nonenzymatic glucose sensors are coming ever closer to being used in practical applications. Bimetallic catalysts have been shown to be superior to single metal catalysts in that they have greater activity and selectivity. Here, we demonstrate the preparation, characterization, and electrocatalytic characteristics of a new bimetallic Pt/Au nanocatalyst. This nanocatalyst can easily be synthesized by electrodeposition by sequentially depositing Au and Pt on the surface of a boron-doped diamond (BDD) electrode. We characterized the nanocatalyst by scanning electron microscopy (SEM), X-ray diffraction (XRD), and voltammetry. The morphology and composition of the nanocatalyst can be easily controlled by adjusting the electrodeposition process and the molar ratio between the Pt and Au precursors. The electrocatalytic characteristics of a Pt/Au/BDD electrode for the nonenzymatic oxidation of glucose were systematically investigated by cyclic voltammetry. The electrode exhibits higher catalytic activity for glucose oxidation than Pt/BDD and Au/BDD electrodes. The best catalytic activity and stability was obtained with a Pt:Au molar ratio of 50:50. Moreover, the presence of Au can significantly enhance the long-term stability and poisoning tolerance during the electro-oxidation of glucose. Measurements of glucose using the Pt/Au/BDD electrode were linear in the range from 0.01 to 7.5mM, with a detection limit of 0.0077mM glucose. The proposed electrode performs selective electrochemical analysis of glucose in the presence of common interfering species (e.g., acetaminophen, uric and ascorbic acids), avoiding the generation of overlapping signals from such species.

Storage of Nitrous Oxide (NOx) in Diesel Engine Exhaust Gas using Alumina-Based Catalysts: Preparation, Characterization, and Testing

This work investigated the nitrous oxide (NOx) storage process using alumina-based catalysts (K2 O/Al2 O3 , CaO/Al2 O3, and BaO/Al2 O3 ). The feed was a synthetic exhaust gas containing 1,000 ppm of nitrogen monoxide (NO), 1,000 ppm i-C4 H10 , and an 8% O2 and N2 balance. The catalyst was carried out at temperatures between 250–450°C and a contact time of 20 minutes. It was found that NOx was effectively adsorbed in the presence of oxygen. The NOx storage capacity of K2 O/Al2 O3 was higher than that of BaO/Al2 O3. The NOx storage capacity for K2 O/Al2 O3 decreased with increasing temperature and achieved a maximum at 250°C. Potassium loading higher than 15% in the catalyst negatively affected the morphological properties. The combination of Ba and K loading in the catalyst led to an improvement in the catalytic activity compared to its single metal catalysts. As a conclusion, mixed metal oxide was a potential catalyst for de-NOx process in meeting the stringent diesel engine exhaust emissions regulations. The catalysts were characterized by a number of techniques and measurements, such as X-ray diffraction (XRD), electron affinity (EA), a scanning electron microscope (SEM), Brunner-Emmett-Teller (BET) to measure surface area, and pore volume and pore size distribution assessments.

Synthesis of Nano-catalysts by Induction Suspension Plasma Technology (SPS) for Fischer–Tropsch Reaction

Nanometric catalysts were synthesized through induction suspension plasma technology (SPS) for application in the Fischer–Tropsch synthesis (FTS). Carbon-supported single metal catalysts (Co/C, Fe/C), bimetallic formulations (Co–Fe/C), and ternary (Co–Fe–Mo and Co–Fe–Ni) systems have been considered in this work. SPS has been selected because it simultaneously allows for: (1) atomizing and generating metallic nanoparticles; (2) creating particularly Fe carbides, which are important in Fe-based FTS reaction mechanism; (3) in situ production of the nanometric graphitic-carbon matrix; and (4) saving time in catalyst synthesis, limiting sample preparation steps and eliminating post synthesis treatment before use. Porosity measurements by the Brunauer–Emmett–Teller method indicate that the samples are essentially non-porous. The synthesized catalysts characterized by X-ray Diffraction analysis show the presence of both metallic and carbidic species. The graphitic-carbon matrix has substantial structural defects that make it partly amorphous. Scanning Electron Microscopy analysis coupled with Energy Dispersive X-ray Spectroscopy mapping shows uniform dispersion of the metal moieties in the carbon support. Analysis by Transmission Electron Microscopy imaging displays metal nanoparticles with mean particle size within the 9–15 nm range enveloped in the carbon matrix.

Effects of Pb in Electrocatalysis of Ethanol Oxidation Reaction on Pd/C and Pdru/C Catalysts in Alkaline Media

Electrocatalysis of ethanol oxidation reactions (EORs) in alkaline media has gained great research interests due to the development of alkaline anion exchange membranes. The EOR kinetics are more facile in alkaline media than those in acid media. The most importantly, there are more choices of materials to be used as the electrocatalysts for the EOR since these materials are stable in the alkaline media, but not in the acid media. Although extensive research has been done worldwide related to electrocatalysis of EORs in both acid and alkaline media, the EOR mechanisms are still not well understood. It still remains as a major challenge of reducing the overpotentials of EORs in low temperature fuel cells. The oxidation of ethanol in alkaline media is very complicated and involves many types of intermediates, such as C1 species (most likely COad and CHx,ad), OHad, CH3COad and other forms of acetaldehyde in alkaline media. Single metal catalysts are often found to perform much poorer than those modified with the second metal. “Multi-functional” electrocatalyst systems have been designed and tested for EORs. In this work, we aim to study effects of Pb on electrocatalysis of EORs on Pd/C and PdRu/C catalysts in alkaline media.Pd/C and Pd2Ru/C (the atomic ratio of Pd:Ru is 2:1) catalysts with 20 wt. % Palladium loading were prepared by an impregnation method. The morphologies of the catalysts were studied by transmission electron microscope (TEM) and x-ray diffraction (XRD) characterizations. Then the catalysts were performed electrochemical characterizations in a standard tri-electrode electrochemical cell with a graphite column serving as the counter electrode and a Hg/HgO/1.0 M OH- electrode (0.098 V vs. NHE) as the reference electrode in an argon-saturated or ethanol-contained 1 M NaOH solution without or with 1mM lead(II) acetate (Sigma-Aldrich) presented.The EOR activities of the catalysts were also characterized with a single direct ethanol fuel cell. The membrane electrode assemblies (MEA) with an active electrode area of 4.5 cm2 were comprised of a catalyst coated membrane (CCM), a Ni foam (Hohsen Corp.) as the anode backing layer and a TGP-H-090 carbon paper (Toray) as the cathode backing layer. The anode catalyst ink was prepared by mixing the 16mg catalyst (Pd/C and Pd2Ru/C) with Nafion solution. The cathode catalyst ink was prepared by ultrasonicating 8mg MnO2 nanorod catalyst, 8 mg active carbon (BP2000, Cabot Corp. ) and the A4 ionomer (Tokuyama Co.). The catalyst/ionomer (Nafion or A4) weight ratio is kept at 80:20 in both anode and cathode. A fuel cell test system (Scribner Associates Model 850e) was used for controlling the cell temperature, cathode humidity, O2 flow rate. The temperature of the fuel cell was maintained with a tolerance of ± 0.2 °C. The anode solution flow rate was controlled ESI's MP2 micro peripump (elemental scientific Inc.)CV curves were obtained with the Pd/C and Pd2Ru/C in Ar-saturated 1.0 M NaOH or 1.0 M ethanol and 1.0 M NaOH solution without or with 1mM Pb2+ presented. From the CV curves obtained in the 1.0 M NaOH solutions, the Pb2+ presence in the solution was found to alter surface characteristics on both Pd/C and PdRu/C catalysts. The EOR activities were also affected accordingly. Both CV and chronoamperometry (CA) measurements indicate that the presence of Pb2+ in the solution leads to the reduction of EOR kinetics on the Pd/C or PdRu/C catalysts, which are different from what were observed with Pt-based catalysts. Detailed fuel cell characterizations of these various catalysts were performed. Combining the electrochemical measurements and fuel cell test results, effects of Pb on the electrocatalysis of EOR on Pd/C and PdRu/C catalysts in alkaline media will be discussed.