Galvanic Displacement Research Articles

Effect of an Organic Additive, N-Dimethyldithiocarbamic acid Ester Sodium salt, on Properties of Bismuth Telluride thin Films Fabricated by Galvanic Displacement Reaction of Electroplated Cobalt thin Films

Effect of an Organic Additive, N-Dimethyldithiocarbamic acid Ester Sodium salt, on Properties of Bismuth Telluride thin Films Fabricated by Galvanic Displacement Reaction of Electroplated Cobalt thin Films

Top-Open Hollow Nanocubes of Ni-Doped Cu Oxides on Ni Foam: Scalable Oxygen Evolution Electrode via Galvanic Displacement and Face-Selective Etching.

Self-standing and cost-effective electrodes for high-performance oxygen evolution reaction (OER) are vital for emerging energy storage and conversion technologies. We report a scalable binder-free OER electrode with open hollow nanocubes of Ni-doped CuOx on Ni foam (hNC/NF) through spontaneous galvanic displacement followed by simple electrochemical oxidation. Face-selective etching for the unique structure of hollow nanocubes with large open ends is achieved by utilizing the different accessibility of the top and side faces of cubes to solution species, more specifically the depletion of reactants between the densely supported nanocubes. Besides, the in situ deposition on Ni foam allows spontaneous Ni doping, which, as revealed by DFT calculations, fortunately strengthens the adsorption of oxygenated intermediates and therefore could optimize the free energy path of OER on Cu oxides. Benefiting further from the high accessible surface area of the unique open hollow architecture, the hNC/NF exhibits an outstanding OER activity with a small overpotential (η = 305 mV at 10 mA cm-2) as well as excellent stability without significant decay after 120 h operation. To our knowledge, this should represent the best OER performance of Cu-based electrocatalysts and is competitive with those based on Fe-group metals. Besides, the hNC/NF-based water electrolyzer delivers a performance of 1.50 V cell voltage at 10 mA cm-2, offering great promise for practical application.

Enhancing ORR Performance of Bimetallic PdAg Electrocatalysts by Designing Interactions between Pd and Ag

Precise tuning of the electronic properties of Ag/C using under potentially deposited (UPD) Cu and subsequent galvanic displacement to deposit atomically dispersed loading of Pd resulted in a robus...

Fabrication of fully covered Cu–Ag core–shell nanoparticles by compound method and anti-oxidation performance

Cu–Ag core–shell nanoparticles with a size of 8 nm were synthesized by the compound method of replacement reaction and chemical reduction reaction. A fully covered Cu–Ag core–shell structure was obtained by controlling the two different silver sources and electroless silver plating time. The optimum condition uses silver ammonia reacted for 14 h. The process of electroless silver plating uses the mixed growth model of layered growth and island growth. Silver atoms firstly attach to the surface of the as-prepared copper nanoparticles to form the dotted Ag atom structure by galvanic displacement reaction between Cu and [Ag(NH3)2]+, and then more silver atoms, reduced by sodium citrate, gradually deposit on the copper surface to form a fully covered structure. The morphology and core–shell structure of the nanoparticles was observed by scanning electron microscopy, transmission electron microscopy and x-ray diffraction. The simultaneous thermal analyzer results confirmed that the weight gain of Cu–Ag core–shell nanoparticles was 2.2% when heated up to 400 °C, which was lower than pure Cu nanoparticles. According to the x-ray photoelectron spectroscopy results, the Cu–Ag core–shell nanoparticles exhibited good anti-oxidation performance compared with the pure copper nanoparticles after being stored for one month under the ambient conditions.

Rational construction of Au–Ag bimetallic island-shaped nanoplates for electrocatalysis

Active electrocatalysts are the key to water splitting for hydrogen production through the electrolysis. In this paper, 50 nm silver nanoplates were used as templates for synthesis of Au–Ag island-shaped nanoplates by controlling the surface chemistry. The guiding mechanism of polyvinylpyrrolidone (PVP, Mw = 40 000) to Au–Ag island-shaped nanoplates crystal was also further investigated. It is found that the surface energy of Ag nanoplates between (100) and (111) crystal planes can be regulated by varying the amount of PVP in the system. Then a uniform Au-Ag triangular island nanostructure was obtained. Compared with the Ag nanoplates catalysts, the Au–Ag island nanoplates catalysts show the superior catalytic performances in hydrogen evolution electrocatalysis (HER). These results demonstrate a new surface chemistry modification by PVP and a galvanic displacement reaction for designing the active electrocatalysts. More importantly, the Au–Ag island-shaped nanoplates show an unconventional growth mode of preserving the original Ag nano-triangular crystal structure. The enhanced performance in electrocatalysis can be mainly attributed to Au–Ag alloy structure, which allows the appearance of synergistic effects. The present work demonstrates the crucial roles of surface chemistry in catalysts synthesis, which may guide the design of active bimetallic catalysts.

Plasmonic biosensors fabricated by galvanic displacement reactions for monitoring biomolecular interactions in real time

Optical sensors are prepared by reduction of gold ions using freshly etched hydride-terminated porous silicon, and their ability to specifically detect binding between protein A/rabbit IgG and asialofetuin/Erythrina cristagalli lectin is studied. The fabrication process is simple, fast, and reproducible, and does not require complicated lab equipment. The resulting nanostructured gold layer on silicon shows an optical response in the visible range based on the excitation of localized surface plasmon resonance. Variations in the refractive index of the surrounding medium result in a color change of the sensor which can be observed by the naked eye. By monitoring the spectral position of the localized surface plasmon resonance using reflectance spectroscopy, a bulk sensitivity of 296 nm ± 3 nm/RIU is determined. Furthermore, selectivity to target analytes is conferred to the sensor through functionalization of its surface with appropriate capture probes. For this purpose, biomolecules are deposited either by physical adsorption or by covalent coupling. Both strategies are successfully tested, i.e., the optical response of the sensor is dependent on the concentration of respective target analyte in the solution facilitating the determination of equilibrium dissociation constants for protein A/rabbit IgG as well as asialofetuin/Erythrina cristagalli lectin which are in accordance with reported values in literature. These results demonstrate the potential of the developed optical sensor for cost-efficient biosensor applications.Graphical abstract

Pd–Cu alloy catalyst synthesized by citric acid-assisted galvanic displacement reaction for N2O reduction

In this study, the composition-optimized Pd–Cu catalyst for electrochemical N2O reduction in highly alkaline solution was prepared by a galvanic displacement method. The atomic ratio of Pd to Cu in Pd–Cu bimetallic catalyst, which has been known to be hardly controlled using galvanic displacement, was tailored by varying the concentration of citric acid in galvanic displacement bath. With increasing citric acid concentration, the decreased grain size, characterized by X-ray diffraction, and the increased amount of carbon in Pd–Cu catalyst, measured by energy-dispersive X-ray spectrometry, revealed the incorporation of citric acid into the catalyst, which was attributed to the tunable catalyst composition. The incorporation of citric acid into Pd–Cu deposit restrained the diffusion of Cu from Cu substrate to deposit, leading to decrease in the Cu content in Pd–Cu. The electrocatalytic activity for N2O reduction was strongly dependent on the Pd/Cu composition in Pd–Cu catalysts. Among the investigated Pd–Cu catalysts with different compositions, the highest electrocatalytic activity was obtained with Pd60Cu40 with a Tafel slope of 0.096 V dec−1. Moreover, the Pd60Cu40 catalyst showed remarkably enhanced mass-specific activity for N2O reduction, compared with a commercial Pd/C. The density functional theory (DFT) calculations revealed that the highest N2O reduction activity of Pd60Cu40 could be attributed to the facilitation of an adsorption/desorption balance for N2O reduction, resulting from the appropriately lowered d-band center of catalyst.

Supported Ni–Au Colloid Precursors for Active, Selective, and Stable Alkyne Partial Hydrogenation Catalysts

Bimetallic NiAu catalysts have garnered broad interest for a variety of reactions including automotive emissions, selective hydrogenation, selective oxidation, hydrodechlorination, and biomass conversion. However, the bulk immiscibility of the two metals, complicating catalyst synthesis, has limited studies of this bimetallic system. We report a solution-phase synthesis for Ni and bimetallic NiAu heterogeneous catalysts. Using oleylamine as a capping agent, an optimized synthesis for Ni catalysts led to supported particles with a narrow size distribution (4.7 ± 0.4 nm). Gold was added to the Ni nanoparticles via galvanic displacement of Ni in organic solution, the particles were deposited onto commercial alumina, and oleylamine capping agent was removed. The catalytic activity of the bimetallic materials in 1-octyne partial hydrogenation was in between the activity of monometallic Ni and Au catalysts. At high space velocity, the bimetallic catalysts largely maintained the high alkene selectivity associate...

Selective deposition of gold particles onto silicon at the nanoscale controlled by a femtosecond laser through galvanic displacement.

Control of the deposition location and morphology of metals on semiconductors is of considerable importance for the fabrication of metal–semiconductor hybrid structures. For this purpose, selective nanoscale deposition of gold on silicon was successfully achieved by a two-step method in this paper. The first preparation step comprises the fabrication of ripples with a femtosecond laser. The second preparation step is to immerse the samples in a mixed aqueous solution of hydrofluoric acid (HF) and chloroauric acid (HAuCl4). The periodically ablated ripple structures on silicon surfaces fabricated by the femtosecond laser changed the physical and chemical properties of silicon and then controlled the nucleation positions of gold nanoparticles. Gold particles tend to grow in raised positions of the ripples and no substantial growth was observed in the recesses of the ablated ripple structures. Similar phenomena were observed on the modified ripple structures; this led to the formation of periodically distributed gold sub-micron wires. Above all, this paper proposes a new mask-free method of selective metal electroless deposition that can be realized without complicated experimental equipment and tedious experimental operations.

Ag nanosheets grown on Cu nanowire-based flexible films for sensitive non-enzymatic glucose sensors

Cu nanowire (Cu NW) and Ag nanosheet (Ag NS) bimetallic nanocomposites were fabricated on a flexible polyethylene terephthalate (PET) slice for non-enzymatic glucose sensing via a facile two-step approach, vacuum filtration, and galvanic displacement. Low-cost Cu NW-based conductive films were employed as the conductive substrates to substitute the traditional glassy carbon electrodes or indium tin oxide electrodes. The highly stable Ag NSs grow directly on the surface of Cu NWs without additional binders. The AgNO3 concentration and displacement time were adjusted to control the consumption of Cu NWs and the growth of Ag nanostructures. With the large load of Ag and the great connection of Cu NWs, a high sensitivity of 2033 μA mM−1cm−2, a fast amperometric response of 2 s, a wide linear range of 0.0015–4.02 mM, and a satisfactory result in human serum analysis were obtained by this novel Ag NS/Cu NW/PET sensor. Especially the sensitivity of the sensor was over four-fold higher than that of pure Cu NWs/PET, benefiting from the synergistic effect of bimetals. Furthermore, the Ag NS/Cu NW/PET sensor demonstrated a stable amperometric signal against mechanical bending. The material holds promise to use to fabricate flexible electrochemical devices.

Applications of cathodic Co100-XNiX (x = 0, 30, 70, and 100) electrocatalysts chemically coated with Pt for PEM fuel cells

The present work comprises a study about the synthesis, characterization, and performance evaluation of four Co100-X-NiX (x = 0, 30, 70, and 100) electrocatalysts coated with Pt with potential catalytic activity towards ORR. Electrocatalysts were prepared through a two-stage process combining the versatile high-energy ball milling synthesis and the galvanic displacement method. On a first stage, high-energy ball milling was used to produce nanoparticles of non-noble transition metals, (M = Co100 and Ni100) and (BM = Co30Ni70and Co70Ni30). On a second stage, galvanic displacement reactions via chemical reflux treatment were employed to promote a Pt coating over the milled nanoparticles. The four electrocatalysts were dispersed on Vulcan carbon maintaining a metal:carbon (wt.%) ratio of 50:50 each one. The result was two type of systems: (M-Pt/C = Co100–Pt/C and Ni100–Pt/C) and (BM-Pt/C = Co30Ni70–Pt/C and Co70Ni30–Pt/C). All the electrocatalysts presented a final composition: ~10 wt%. of Pt, ~40 wt% of Co100-xNix, and ~50 wt% of Vulcan carbon. Physical characterization of the synthesized electrocatalysts involved XRD, STEM, AAS-ICP-MS and EDS-SEM studies confirming the formation of homogeneously-distributed metallic nanoparticles on the carbon. The electrochemical evaluation, through cyclic voltammetry and steady-state polarization curves using rotating disk electrode technique, was performed for the four synthesized electrocatalysts and for a commercial platinum-loaded carbon black (Pt Etek 20 wt%) catalysts. All four synthesized electrocatalysts were electroactive for ORR. Moreover, the Ni100–Pt/C electrocatalyst presented the highest mass activity whereas Co30Ni70–Pt/C electrocatalyst showed the major stability after 3000 cycles of accelerated degradation test than the others. Two membrane electrode assemblies (MEAs) for PEM fuel cell were fabricated with the synthesized Ni100–Pt/C and Co30Ni70–Pt/C electrocatalysts used as cathodes. Results under single-fuel cell operation showed the same performance trend for those materials that observed under electrochemical glass cell conditions.

Formation of a Au/Au9Ga4 Alloy Nanoshell on a Bacterial Surface through Galvanic Displacement Reaction for High-Contrast Imaging.

The spontaneous electron transfer between GaAs and ionic gold through the galvanic displacement reaction results in the formation of gold nanoparticles and a Au9Ga4 alloy. We investigated this process for decorating Legionella pneumophila and Escherichia coli, aiming at enhanced imaging of these bacteria. The surface of bacteria was modified with gold ions through the electrostatic linkage of ionic liquids with phosphate units of the bacterial cell wall. The modified bacteria were further incubated with an antibody-functionalized GaAs substrate. Due to a large gap in the reduction potential of gold and gallium ions, the induced reaction involving bacteria resulted in a reduction of the gold ions to gold nanoparticles and oxidation of GaAs to Ga2O3 and a Au9Ga4 alloy. The bacteria covered with a Au/AuGa nanoshell, if excited at 377 nm, show a bright emission at 447 nm originating from Au/Au9Ga4. This approach offers a simple and potentially less expensive method for high-contrast imaging of bacteria in comparison to the conventional methods of staining with different dyes or by conjugating green fluorescent proteins.

A composite film prepared from titanium carbide Ti3C2Tx (MXene) and gold nanoparticles for voltammetric determination of uric acid and folic acid

In this study, a solution-processing based galvanic deposition approach is described for in-situ deposition of gold nanoparticles (AuNP) on delaminated titanium Ti3C2Tx nanosheets under ultrasonication. The nanocomposite (AuNP@Ti3C2Tx) was placed on a glassy carbon electrode (GCE) and then applied to electrochemically with label-free, and simultaneously sense uric acid (UA), and folic acid (FA) at physiological pH. The modified GCE has attractive figures of merit: (i) The working potentials for UA and AA are well separated (+0.35V and 0.70V vs. Ag|AgCl); (ii) wide linear responses (from 0.03-1520μM for UA and from 0.02-3580μM for FA; (iii) good electrochemical sensitivities for both UA and FA (0.53 and 0.494μAμM-1.cm-2, respectively), and (iv) detection limits of 11.5nM (UA) and 6.20nM (FA). The electrode exhibited good repeatability (RSD = 4.4%), acceptable reproducibility (RSD = 4.1%), and excellent stability (91.8% over one-month storage). The method was applied to analyze spiked serum samples, and modified GCE is shown appreciable recoveries (97.1-98.8% and 96.8-98.0% for UA, and FA, respectively). Graphical abstractA photograph (top left) of colloidal suspension of gold nanoparticles (AuNPs). They were grown onthe delaminated titanium carbide Ti3C2Tx MXenenanosheet via galvanic displacement deposition method, and their corresponding a low-resolution transmission electron microscopy micrograph (top right) of AuNP@Ti3C2Tx. The graphical representation of AuNP@Ti3C2Tx drop-casted on glassy carbon electrode (GCE) (bottom left), and their voltammetric measurement were applied in the presence of both uric acid and folic acid with increasing the concentration of both analytes (bottom right).

Reinvestigation of nucleation and growth of Zn on Al surface during modified alloy zincating

Modified alloy zincate (MAZ) is a surface-treatment process for depositing Zn on Al by galvanic displacement reaction prior to application of functional coatings. Two-step zincating i.e. double zincating (DZ) is a preferred technique in comparison to single zincating (SZ) because of imparting excellent adhesion of coatings on Al. Prior to second step of zincating during DZ, the single zincated Al substrate undergoes nitric dissolution. In this study, the intriguing role of this nitric acid etching on second step nucleation and growth of Zn has been investigated in detail. For this, time dependent Zn-nucleation and growth morphology on Al surface was monitored by AFM and FESEM examinations and revealed scattered but coarse nucleation during SZ; and finer nucleation along with uniform coverage of Zn during DZ. Post single zincating, nitric acid etch led to generation of micro/nanoporous Al surface as revealed by microscopic investigations. The porous Al surface along with trace amount of noble metals such as Cu and Fe was found to play significant role on Zn root growth into Al matrix and fine grain Zn deposit on top surface confirmed by cross-section FESEM analysis of focused ion beam (FIB) cut Zn/Al sample. Rutherford Backscattering Spectroscopy (RBS) was used as a non-destructive technique to estimate Zn film thickness and growth rate. The observed Zn nucleation and growth results were further substantiated by analyzing the open circuit potential (OCP) data during zincating. Difference in nucleation and growth pattern of Zn on Al surface during SZ and DZ was fundamentally understood with the help of classical nucleation theory and galvanic kinetics.

Poly (3, 4-ethylene dioxythiophene) Supported Palladium Catalyst prepared by Galvanic Replacement Reaction for Methanol Tolerant Oxygen Reduction

Herein, we propose a facile electrochemical approach for the synthesis of Pd loaded poly 3, 4-ethylenedioxythiophene (PEDOT) electrodeposited on glassy carbon electrode (GCE) resulting in high surface area. The catalyst preparation is initiated with EDOT polymerization on GCE surface by electrochemical potential cycling method, followed by the electrodeposition of Cu from a 2 mM solution of CuSO4 in 0.1 M NaClO4 at a constant potential of +0.34 V vs. SHE in the form of Cu nanocubes on the PEDOT surface. Pd-PEDOT catalyst was then prepared by the partial substitution of copper by galvanic displacement with various concentrations of PdCl2. The prepared Pd/PEDOT electrocatalyst is found to be methanol resistant indicating its usefulness as fuel cell cathode. The prepared catalyst supports two electron transfer of oxygen reduction reaction in 0.5 M H2SO4. The effects of Pd and Cu contents and the quantity of PEDOT, mass and specific activities were studied. At a relatively low Pd loading of 0.57 ng/cm2, the Pd/PEDOT should be a cost-effective alternative cathode catalyst for direct methanol fuel cells, DMFCs. This work explains the usefulness of PEDOT as good catalyst supporting material which is prepared by an eco-friendly electrochemical route.

Galvanic displacement on electrodeposited tangled Zn nanowire sacrificial template for preparing porous and hollow Ni electrodes in ionic liquid

Tangled-Zn nanowire-composed porous structures were prepared via electrodeposition at particular applied potentials in an amide-type ionic liquid 1-butyl-1-methylpyrrolidinium bis((trifluoromethyl)sulfonyl) amide (IL [BMP][TFSA]) containing ZnCl2. The porous Zn was used as a sacrificial template for preparing a porous nickel duplicate via galvanic displacement in [BMP][TFSA] containing [NiCl4]2−. The solid tangled Zn-nanowires were converted to hollow NiZn-nanotubes in which a typical galvanic displacement reaction occurred through the alloying/dealloying mechanism, and the Kirkendall effect might also took place to form the bi-walled tubes at some spots. In general, the atomic content of Ni exchanged from Zn increased with the increment of reaction time, concentration of [NiCl4]2−, and temperature. The obtained NiZn could be almost completely dealloyed as verified by the XPS analyses to form a porous Ni electrode that displayed high stability and activity to electrooxidation of urea in alkaline solutions. This study indicated that [BMP][TFSA] played a crucial role on successfully cloning porous Ni from its Zn counterpart.

From bimetallic PdCu nanowires to ternary PdCu-SnO2 nanowires: Interface control for efficient ethanol electrooxidation

At present, although a large number of palladium-based nanowire electrocatalysts have been prepared, there are few reports on nanowires containing rich metal oxides. Herein, porous PdCu alloy nanowires and PdCu-SnO2 nanowires were prepared by using a galvanic displacement synthesis method. Due to their one-dimensional structure, rough surfaces with non-homogeneous edges, electronic effect, and the advanced PdCu/SnO2 interface of the as-synthesized PdCu-SnO2 nanowire catalysts, they exhibited a mass activity of 7770.0 mA mg−1 towards ethanol oxidation, which was 7.6-fold higher than that of Pd/C catalysts (1025.0 mA mg−1). In addition, they behaved strong durability upon chronoamperometry and continuous cyclic voltammetry tests. The electrochemical measurements demonstrated that SnO2 was introduced into the PdCu/SnO2 interface, which promoted the oxidation of ethanol at a lower potential and accelerated the oxidation of Pd-COads via SnO2-OHads to regenerate the active sites. This research highlights the significance of introducing metal oxides into the nanostructure interface, and the performance of Pd-containing catalysts towards ethanol oxidation reaction was greatly improved.

High Performance Direct N2H4-H2O2 Fuel Cell Using Fiber-Shaped Co Decorated with Pt Crystallites as Anode Electrocatalysts

In this study, a fiber-shaped Co coating was electroplated on the Cu surface followed by the deposition of Pt crystallites using the galvanic displacement method. The electrochemical behavior of the prepared Cofiber and Pt nanoparticles decorated Cofiber catalysts were evaluated in order to provide insights into the electro-oxidation of N2H4 in an alkaline media was performed using cyclic voltammetry and chrono-techniques. The influence of Cofiber/Cu and PtCofiber/Cu as the anode electrocatalyst on the performance of direct N2H4-H2O2 fuel cell was investigated at different temperatures. The deposition of a small amount of Pt crystallites, in the range of 5 μgPt cm–2 to 29 μgPt cm–2, significantly improved the performance of the fiber-shaped Co catalyst for the electro-oxidation of N2H4 in an alkaline medium. The measured N2H4 oxidation current densities at −0.2 V are approximately 5–6 times larger for different PtCofiber/Cu catalysts, compared with that of a pure Cofiber/Cu. The single N2H4-H2O2 fuel cell results showed that the highest peak power density of 219.8 mW cm–2 for the N2H4-H2O2 fuel cell was obtained with the PtCofiber/Cu catalyst that has the Pt loading of 28.7 μgPt cm–2.

Galvanic displacement reaction of nickel to form one-dimensional trigonal tellurium structures in acidic solutions

Trigonal tellurium micro-wires and tubes were synthesized by galvanic displacement of nickel in acidic sulfate solutions where the growth mechanism was elucidated using various electroanalytical methods and material characterization. The effects of solution composition, including concentrations of tellurium precursor and sulfate, were studied. The transition from micro-wires to tubes with an increase in HTeO2+ concentration was observed, which might be attributed to the comparable diffusion length scale of tellurium on the cylindrical seed surface to the radius of the seed. On the other hand, increasing H2SO4 concentration led to transformation of microtubes to microwires owing to reduction deposition rate and limited mass transfer of HTeO2+ ions. The effect of other anions (i.e., Cl− and NO3−) on galvanic displacement reaction was also studied. As a strong oxidant, HNO3 dissolved nickel faster than SO4−2 and Cl−, but showed slower tellurium deposition tellurium nanowires, which might be due to co-reduction of nitrate ions. The preferential adsorption of Cl− increased both dissolution of nickel and the deposition of tellurium, resulting in larger tellurium microtubes.

An easy and eco-friendly method to fabricate three-dimensional Pd-M (Cu, Ni) nanonetwork structure decorated on the graphene nanosheet with boosted ethanol electrooxidation activity in alkaline medium

A new rapid and facile strategy for the preparation of Pd-Ni/G and Pd-Cu/G catalysts with a three-dimensional porous structure are presented in this paper. Both catalysts are formed using the same strategies in two steps: 1) The reduction of Ni(OH)2 and Cu(OH)2 to the metallic form on the surface of G/GC Electrode using the Zn/HCl reducer, 2) The galvanic displacement of Ni and Cu by Pd2+. Afterwards, three-dimensional Pd nanonetwork is generated on the glassy carbon electrode via the galvanic displacement. Compared to the other routes, this strategy depicts several advantages (e.g. fast way, facile, surfactant and reductant free, cheap, and eco-friendly.) Both catalysts are applied towards Ethanol Oxidation Reaction (EOR). Both porous structures show higher electrocatalytic activity and stability toward EOR compared to the commercial Pd/C. The extraordinary catalytic activity and durability of the both proposed catalysts for EOR can be related to the two vital reasons:1) The combination of Ni and Cu with Pd will efficiently promote the catalytic performance of Pd-Ni/G and Pd-Cu/G samples due to synergetic effects. 2) The porous structure of the as-prepared catalysts renders a high surface area and leads easier mass transport through the pores.