Electrocatalysts based on low amounts of palladium combined with tin nanoparticles and cerium dioxide nanorods for application as ADEFC anodes

This study demonstrates the structural properties and evaluates the electrocatalytic activity of an ethanol oxidation reaction using ternary materials composed by Pd and Sn nanoparticles combined with CeO₂ nanorods (NR) anchored on Vulcan carbon black to be used as an anode in alkaline direct ethanol fuel cells (ADEFCs). The highest open circuit voltage (1010 mV), maximum power (30 mW cm⁻²) and current densities (113 mA cm⁻²) were achieved using (Pd₁Sn₃)₁₀(CeO₂ NR)₂₀(Vn)₇₀, while the commercial anode values were 968 mV, 23 mW cm⁻² and 123 mA cm⁻². Although similar performance for both anodes was observed, the ternary hybrid electrocatalyst contains an 8-fold lower Pd content than the commercial material. This outcome may be justified by the higher defect density presented by the carbon support observed by Raman spectroscopy and the metal oxidation state modifications detected by X-ray photoelectron spectroscopy, as well as the electrochemically active surface area presented by the ternary electrocatalyst. The combination of higher vacancies, defects and oxygenated species in the carbon support and the synergistic effect between the oxyphilic Sn and CeO₂ NR species and the Pd nanoparticles results in an electrochemical performance that makes these ternary electrocatalysts promising anode materials for ADEFC applications.     

Electrodeposited graphene hybridized graphitic carbon nitride anchoring ultrafine palladium nanoparticles for remarkable methanol electrooxidation

Exploiting high performance electrocatalysts is crucial for the effective electrooxidation of methanol, although some barriers exist. Herein, we develop a hybrid support composed of graphitic carbon nitride (g-C₃N₄) and reduced graphene oxide (rGO) synergistically anchoring sufficient ultrafine palladium (Pd) nanoparticles via a simple one-step electrodeposition technique. The morphology and structure were characterized by scanning/transmission electron microscopy, X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy, which confirmed that the Pd nanoparticles were massively and uniformly dispersed on the support of g-C₃N₄@rGO with a the average particle size of 5.87 nm, deriving from the nitrogen in g-C₃N₄ contributing to the electron transport highway on the rGO nanosheet layer surface. Furthermore, electrochemical results suggested that the Pd/g-C₃N₄@rGO showed a high electrocatalytic efficiency for methanol oxidation with a high current density reached 0.131 mA cm⁻². Based on a novel approach to the g-C₃N₄@rGO hybrid nanostructure, this work offers a promising method for the design and synthesis for the superior performance methanol electrocatalyst.     

Electrocatalytic performances of oxygen-deficient titanium dioxide nanosheet coupled palladium nanoparticles for oxygen reduction and hydrogen evolution reactions

The development of multifunctional electrocatalysts is crucial for enhancing the efficiency of electrochemical conversion in energy devices. Here we have synthesized TiO_2-x nanosheets (NSs) supported metallic Pd nanoparticles (Pd/TiO_2-x NSs) as an electrocatalyst using a simple impregnation process. High electrochemical surface areas (ECSAs) and strong metal support interactions (SMSI) of the electrocatalyst showed improved ORR performance throughout a wide pH range under ambient conditions. The outstanding durability of the catalyst was proven by the square-wave potential cycling experiment at 60 °C. Additionally, it was shown that Pd/TiO_2-x NSs showed improved HER activity and stability in 0.5 M H₂SO₄. The catalyst had an overpotential of 19.5 mV for the 10 mA cm⁻² and a low Tafel slope of 41 mV dec⁻¹. The catalyst also showed higher stability for about 30 h in HER performance. This work will help in rationally building nanostructured electrocatalysts loaded on carbon-free support for efficient electrochemical energy storage devices.     

Pd nanoparticles on self-doping-defects mesoporous carbon supports for highly active ethanol oxidation and ethylene glycol oxidation

The high activity electrocatalysts with low cost are crucial for large-scale direct alcohol fuel cells (DAFCs) applications. In this study, the “self-doping-defects” mesoporous carbon (SDMC) as support of uniformly-dispersed Pd nanoparticles (Pd/SDMC) was prepared for high active electrooxidation by a simple route without additional surfactant and acid treatment. According to the mutually corroborated experimental and theoretical calculation results, our route can significantly increase the carbon defect, which is conducive to the anchoring and uniform distribution of Pd nanoparticles. Meanwhile, the uniquely and hierarchically mesoporous nanostructure of SDMC provides abundant pathways for mass transport in the electrooxidation reaction. Benefitting from the above advantages, Pd/SDMC exhibits superior activity than commercial Pd/C and previously reported carbon-based electrocatalysts. The mass activities and specific activities of Pd/SDMC toward ethanol oxidation reaction (EOR) are 3404.3 mA mg⁻¹, 4.48 mA cm⁻², respectively. The mass activities and specific activities of Pd/SDMC for ethylene glycol oxidation reaction (EGOR) are 4002 mA mg⁻¹, 5.26 mA cm⁻², respectively. We believe that the facile strategy to synthesis mesoporous carbon with “self-doping” defects would promote large-scale DAFCs applications in the future.     

Carbon nanotube-copper oxide-supported palladium anode catalysts for electrocatalytic enhancement in formic acid oxidation

Pd/xCuO–10CNT (x = 1, 2, 3, 4) catalysts were synthesized using an improved polyol method. Uniformly prepared catalyst structures and chemical compositions of the catalysts delivered a high oxidation performance. The prepared catalysts were characterized via transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The formation of homogenous active Pd metal and CuO nanoparticle-modified CNT surfaces was found. Meanwhile, the electrocatalytic activity and the long-term stability performance of the prepared catalysts toward formic acid oxidation reaction (FAOR) were also employed via cyclic voltammogram (CV) and chronoamperometry (CA), respectively. Prominently, the prepared Pd/xCuO–CNT nanocomposite catalyst presented an outstanding electrocatalytic performance with a higher maximum forward peak current density (26.9 mA cm^?2) than those of catalysts Pd/CNT (3.4 mA cm^?2) and Pd/C (2.3 mA cm^?2) toward FAOR in the H₂SO₄ electrolyte, representing high conductivity CNT, and dispersed Pd nanoparticles with a large active surface area, on the CuO-CNT support. Additionally, the prepared catalysts also had outstanding stability and an excellent CO poisoning tolerance through the modified Pd structures on CuO-supported CNT. The insertion of CuO onto the CNT surface before Pd loading provided additional electrochemical active sites due to the enhanced geometric and bifunctional system. CuO supports the adsorption of oxygen-containing species (OH_ads) on the catalyst surface, and the electron effect among Pd and Cu metals is beneficial for charge transfer.     

Remarkable electrocatalytic activity of Ni-nanoparticles on MOF-derived ZrO2-porous carbon/reduced graphene oxide towards methanol oxidation

In the present work, a porous carbonaceous platform containing zirconium oxide was used for spreading Ni nanoparticles, and applied to methanol oxidation. The platform was obtained by calcination of a metal-organic framework (MOF) attached to graphene oxide. Nickel nanoparticles were then deposited on the nanocomposite by chemical reduction from a Ni²⁺ solution. The obtained electrocatalyst was characterized by different methods. An excellent electrocatalytic behavior was observed towards methanol oxidation in alkaline medium (j ~ 240 mA cm^?2 or ~ 626 mA mg^?1 in 1.0 M methanol). The results of methanol oxidation by various electrochemical studies (cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry and chronopotentiometry) revealed the effective synergy between reduced graphene oxide, porous carbon material, ZrO₂ metal oxide and Ni nanoparticles. Good durability and stability of the proposed electrocatalyst and significantly increased current density of methanol oxidation suggest it as a potential alternative for Pt-based electrocatalysts in direct methanol fuel cells.     

A robust electrocatalytic activity and stability of Pd electrocatalyst derived from carbon coating

Palladium (Pd) as an efficient anodic catalyst has been extensively investigated in direct formic acid fuel cells (DFAFCs); while, Pd catalyst is electrochemically unstable in acidic electrolyte resulting in low stability retarding the widespread application of DFAFCs. In this study, a new method is invented to prevent the Pd nanoparticles from rapid dissolution by carbon layer originated from the carbonization of glucose. Ascribing to the presence of carbon layer, Pd electrocatalyst demonstrates much higher stability in comparison with Pd electrocatalyst without carbon layer in the course of stability tests. Robust electrocatalytic activities toward formic acid and methanol/ethanol oxidation are observed for carbon-stabilized Pd electrocatalyst resulted from the higher content of metallic Pd atoms coming from the carbonization process, in which Pd (II) species are further reduced. Moreover, the fuel cell performance of carbon-stabilized Pd electrocatalyst reaches 90 mW cm_Pd⁻² measured with 1 M formic acid; while, power density of bare Pd electrocatalyst is only 74 mW cm_Pd⁻². This work highlights that carbon layer carbonized from glucose improves not only the stability of Pd electrocatalyst, but also the electrocatalytic activity.     

Microwave assisted synthesis of nitrogen doped and oxygen functionalized carbon nano onions supported palladium nanoparticles as hybrid anodic electrocatalysts for direct alkaline ethanol fuel cells

In this study, we present the synthesis of pristine carbon (p-CNO), nitrogen doped (N–CNO) and oxygen functionalized (ox-CNO) nano onions, using flame pyrolysis, chemical vapour deposition, and reflux methods, respectively. Pd/p-CNO, Pd/N–CNO and Pd/ox-CNO electrocatalysts are prepared using a simple and quick microwave-assisted synthesis method. The various CNO and Pd/CNO electrocatalysts are fully characterized and the FTIR and XPS results reveal that the synthesized CNOs contain oxygen and nitrogen functional groups that facilitates the attachment and dispersion of the Pd nanoparticles. Electrochemical tests show that the N–CNO and Pd/N–CNO electrocatalysts exhibit high current density (4.2 mA cm ^?2 and 17.4 mA cm ^?2), long-term stability (1.2 mA cm ^?2 and 6.9 mA cm ^?2), and fast electron transfer when compared to the equivalent pristine and oxidized catalysts (and their Pd counterparts), and a commercial Pd/C electrocatalyst, towards ethanol oxidation reactions in alkaline medium.     

One-step synthesis of unique catalyst Ni9S8@C for excellent MOR performances

A novel Ni₉S₈/C electrocatalyst for methanol oxidation reaction (MOR) is synthesized by a simple, cost-effective and one-pot strategy. The electrocatalyst Ni₉S₈ composed of micro and nanoparticles encapsulated inside carbon layers serves as carbon-supporter and fast ion and electron mobilization through the Ni₉S₈/C support materials. The sizes of Ni₉S₈/C nanoparticles range from 2.4 to 7.99 nm, reveals large surface area availability with plenty of active sites for electro-oxidation of methanol. The oxidation performance of electrocatalyst is determined in different solution of methanol and alcohol at various scan rates. At a scan rate of 50 mV s⁻¹, the Ni₉S₈/C catalyst delivers total 52 mA cm⁻² current density for 1.75 V potential (vs RHE) for 1 M KOH and 0.5 M methanol. The electrocatalyst shows low Rct circle and linear chronoamperometric graph for 5000 s, which demonstrate the outstanding stability of the electrocatalyst for methanol electro-oxidation reaction.     

Hydrothermal synthesis of three dimensional reduced graphene oxide-multiwalled carbon nanotube hybrids anchored with palladium-cerium oxide nanoparticles for alcohol oxidation reaction

The synergistic effect of 3D carbon support on Pd-based catalyst and its performance toward direct alcohol oxidation reaction is reported here. The surface of 3DrGO-MWCNTs support was modified by loading different amounts (5–20 wt%) of cerium oxide (CeO₂) by wet impregnation method. Further, Pd nanoparticles were dispersed over CeO₂/3DrGO-MWCNTs nanocomposites by chemical reduction method. The synthesized nanocomposites were characterized by various techniques such as XRD, XRF, SEM, TEM, Raman, and XPS analysis. The electro-oxidation performance and long-term stability of the Pd/CeO₂/3DrGO-MWCNTs electro-catalyst were measured by CV, LSV, and CA analysis. The modification of the catalyst's surface by cerium oxide Pd/10CeO₂/3DrGO-MWCNTs leads to a higher anodic peak current of about138.43 mA/cm² and 91.72 mA/cm² when compared to the Pd/3DrGO-MWCNTs and Pd/C for ethanol and methanol electro-oxidation. In addition, the catalyst showed the highest electro chemical active surface area. The present work demonstrates a possible way to fabricate a nanostructure catalyst to improve the performance of electro-catalytic reactions.     

Preparation of graphite carbon/Prussian blue analogue/palladium (GC/PBA/pd) synergistic-effect electrocatalyst with high activity for ethanol oxidation reaction

In this paper, newly graphite carbon/Prussian blue analogue/palladium (GC/PBA/Pd) synergistic-effect electrocatalyst for ethanol oxidation reaction were developed, with Co-based PBA (Co₃[Co(CN)₆]₂) as a co-catalyst. Structural analysis shows that the Co₃(Co(CN)₆)₂ nanoparticles were highly dispersed and inlaid on surface of GC nanosheets with outstanding structural stability. The GC/Co₃(Co(CN)₆)₂/Pd electrocatalyst exhibits significantly enhanced electrocatalytic activity towards ethanol oxidation with a maximum mass activity of 2644 A g^?1 Pd GC/Pd, which is more than double that of GC/Pd electrocatalyst (1249 A g^?1). Excellent electrochemical stability is also demonstrated for this GC/Co₃(Co(CN)₆)₂/Pd electrocatalyst. The enhanced electrocatalytic activity can be attributed to the synergistic effects of GC support and Co₃(Co(CN)₆)₂ promoter on the Pd electrocatalysts, in which Co₃(Co(CN)₆)₂ acts as a co-catalyst and GC acts as a conductive support.     

Pd,Pd–Ni and Pd–Ni–Fe nanoparticles anchored on MnO2/Vulcan as efficient ethanol electro-oxidation anode catalysts

Pd–Ni–Fe nanoparticles supported on MnO₂/Vulcan XC-72 R (carbon black powder) as the electrocatalyst for the anodic oxidation of ethanol in a direct ethanol alkaline fuel cell (DEAFC) has been conducted. Electrocatalyst structures and morphologies are investigated by XRD, FE-SEM, EDX and elemental mapping techniques and subsequently electrochemical performance of electrocatalysts for ethanol oxidation reaction (EOR) are studied by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). Pd/MnO₂/Vulcan, Pd–Ni/MnO₂/Vulcan and Pd–Ni–Fe/MnO₂/Vulcan efficiently advanced ethanol electro-oxidation reaction under alkaline conditions. Pd/MnO₂/Vulcan revealed best potential window and low charge transfer resistance (R_ct) for EOR. Pd–Ni/MnO₂/Vulcan and Pd–Ni–Fe/MnO₂/Vulcan electrocatalysts have a good anti CO-poisoning capability. Pd–Ni–Fe/MnO₂/Vulcan has significantly high current density, excellent catalyst durability and cyclic stability for ethanol oxidation which encourage researchers for application of such exceptional materials as anode electrocatalysts in DEFC.     

Top-down preparation of Ni–Pd–P@graphitic carbon core-shell nanostructure as a non-Pt catalyst for enhanced electrocatalytic reactions

Electrochemical reactions such as the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and methanol oxidation reaction (MOR) are essential for energy conversion applications such as water electrolysis and fuel cells. Furthermore, Pt or Ir-related materials have been extensively utilized as electrocatalysts for the OER, ORR, and MOR. To reduce the utilization of precious metals, innovative catalyst structures should be proposed. Herein, we report a bi-metallic phosphide (Ni₂P and PdP₂) structure surrounded by graphitic carbon (Ni–Pd–P/C) with an enhanced electrochemical activity as compared to conventional electrocatalysts. Despite the low Pd content of 3 at%, Ni–Pd–P/C exhibits a low overpotential of 330 mV at 10 mA cm^?2 in the OER, high specific activity (2.82 mA cm^?2 at 0.8 V) for the ORR, and a high current density of 1.101 A mg^?1 for the MOR. The superior electrochemical performance of Ni–Pd–P/C may be attributed to the synergistic effect of the bi-metallic phosphide structure and core-shell structure formed by graphitic carbon.     

Aluminum supported palladium nanoparticles: Preparation,characterization and application for formic acid electrooxidation

Palladium nanoparticles were fabricated on the aluminum electrode (Pd/Al) by electrodeposition method through a single step potential from an aqueous solution of 1 mM Pd(NH₃)₄Cl₂. The electrochemical and physical characteristics of the Pd/Al were investigated by cyclic voltammetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) method. Electrochemical measurements in acidic solution indicate that Pd/Al exhibits significantly high electrochemical active surface area (18.32 cm²) with respect to Pd–Al (2.1 cm²) (electroless deposited) and bare Pd (0.28 cm²) electrodes. SEM images and XRD results show that the Pd particles are homogeneously deposited on the surface Al substrate in nanoparticles size between 30 and 50 nm with maximum Pd (111) plane at 2θ angles about of 39°. The Pd/Al was used as electrocatalyst for the oxidation of formic acid (FA) in 0.1 M H₂SO₄ solution. The cyclic voltammetry and chronoamperometry results show that the obtained electrocatalyst, Pd/Al, exhibits high catalytic activity and stability for the electrooxidation of FA. On the other hand, the Pd/Al electrocatalyst has higher catalytic activity for FA oxidation than the comparative Pd–Al and bare Pd electrodes and shows great potential as less expensive electrocatalyst for FA oxidation in direct formic acid fuel cells.     

Pd–Ni–Cu–P metallic glass nanowires for methanol and ethanol oxidation in alkaline media

We demonstrate that Pd₄₃Ni₁₀Cu₂₇P₂₀ bulk metallic glass (BMG) nanowires, prepared by a facile, scalable top-down nanomolding approach, can be used as high surface area electrocatalysts for alkaline alcohol fuel cell applications. These nanowires exhibit higher activity for methanol and ethanol oxidation in alkaline media compared to pure Pd, quantified by cyclic voltammetry. Furthermore, the Pd-BMG nanowire electrocatalyst has a 300 mV lower onset potential for CO oxidation suggesting improved poisoning resistance beyond pure Pd. The Pd-BMG electrocatalyst activation energies for methanol and ethanol oxidation of 22 and 17 kJ mol⁻¹ are lower than the pure Pd values of 38 and 30 kJ mol⁻¹, respectively. Unique properties of BMGs (homogeneity, viscosity, surface tension) facilitate the formability into high surface area electrocatalysts at low processing temperatures. The high electrical conductivity and chemical/physical stability suggest that these materials are ideal candidates for widespread commercial use including energy conversion/storage, hydrogen production, and sensors.     

Zn-substituted MnCo2O4 nanostructure anchored over rGO for boosting the electrocatalytic performance towards methanol oxidation and oxygen evolution reaction (OER)

Mixed valence spinel oxides have emerged as an attractive and inexpensive anode electrocatalyst for water oxidation to replace noble metals based electrocatalysts. The present work demonstrates the facile synthesis of Zn substituted MnCo₂O₄ supported on 3D graphene prepared by simple hydrothermal technique and its application as an electrocatalyst for water oxidation and methanol oxidation. The physico-chemical properties of the nanocatalyst were studied using various microscopic, spectroscopic and diffraction analyses confirming the formation of the composite. The electrocatalytic performance of the prepared electrocatalyst was evaluated using potentiodynamic, potentiostatic and impedance techniques. The synthesized Zn_1-xMn_xCo₂O₄/rGO electrocatalyst with x = 0.2 and 0.4 offered the same onset potential and overpotential at 10 mA/cm². However, catalyst x = 0.4 delivered a higher current density indicating the superiority of the same over other compositions which is attributed to better kinetics that it possessed for OER as revealed by the smallest Tafel slope (80.6 mV dec⁻¹). The prepared electrocatalysts were tested for methanol oxidation in which electrocatalyst Zn_1-xMn_xCo₂O₄/rGO with x = 0.4 shows a better electrochemical performance in oxidizing methanol with the higher current density of 142.3 mA/cm². The above catalyst also revealed excellent stability and durability during both MOR and OER, suggesting that it can be utilized in practical applications.     

Carbon supported Pt hollow nanospheres as anode catalysts for direct borohydride-hydrogen peroxide fuel cells

The carbon supported Pt hollow nanospheres were prepared by employing cobalt nanoparticles as sacrificial templates at room temperature in aqueous solution and used as the anode electrocatalyst for direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared electrocatalysts were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), chronoamperometry (CA), chronopotentiometry (CP) and fuel cell test. The results showed that the carbon supported Pt nanospheres were coreless and composed of discrete Pt nanoparticles with the crystallite size of about 2.8 nm. Besides, it has been found that the carbon supported Pt hollow nanospheres exhibited an enhanced electrocatalytic performance for BH₄⁻ oxidation compared with the carbon supported solid Pt nanoparticles, and the DBHFC using the carbon supported Pt hollow nanospheres as electrocatalyst showed as high as 54.53 mW cm⁻² power density at a discharge current density of 44.9 mA cm⁻².     

High activity of Pd-WO3/C catalyst as anodic catalyst for direct formic acid fuel cell

Pd nanoparticles supported on the WO₃/C hybrid are prepared by a two-step procedure and the catalysts are studied for the electrooxidation of formic acid. For the purpose of comparison, phosphotungstic acid (PWA) and sodium tungstate are used as the precursor of WO₃. Both the Pd-WO₃/C catalysts have much higher catalytic activity for the electrooxidation of formic acid than the Pd/C catalyst. The Pd-WO₃/C catalyst prepared from PWA shows the best catalytic activity and stability for formic acid oxidation; it also shows the maximum power density of approximately 7.6 mW cm⁻² when tested with a small single passive fuel cell. The increase of electrocatalytic activity and stability is ascribed to the interaction between the Pd and WO₃, which promotes the oxidation of formic acid in the direct pathway. The precursors used for the preparation of the WO₃/C hybrid support have a great effect on the performance of the Pd-WO₃/C catalyst. The WO₃/C hybrid support prepared from PWA is beneficial to the dispersion of Pd nanoparticles, and the catalyst has potential application for direct formic acid fuel cell.     

Solvothermal synthesis of Pd10–Ni45–Co45/rGO composites as novel electrocatalysts for enhancement of the performance of DBFC

In this research, three Pd decorated Ni and Co catalyst nanoparticle were synthesized on reduced graphene oxide (rGO) supports are synthesized through a facile solvothermal procedure. Borohydride oxidation reaction (BOR) activity and performance of prepared electrocatalysts respect to NaBH₄ oxidation is evaluated by various electrochemical techniques in the three-electrode and the fuel cell configuration. Among the prepared catalysts, Pd₁₀–Ni₄₅–Co₄₅/rGO exhibits the highest BOR activity. The cyclic voltammograms showed that the measured current at 0.5 V for the electrode of Pd₁₀–Ni₄₅–Co₄₅/rGO is as much as 108 mA cm⁻² higher than Pd₁₀–Ni₉₀/rGO and 185 mA cm⁻² higher than Pd₁₀Co₉₀/rGO. X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectra were employed to study the morphology and crystal structure of the prepared catalyst. The results of DBFC test show that the Pd₁₀–Ni₄₅–Co₄₅/rGO nanoparticles as anodic catalyst, enhanced power density to 50.4 mW cm⁻² which is 10.5% and 45.2% higher than power density of DBFCs with Pd₁₀–Ni₉₀/rGO (45.6 mW cm⁻²) and Pd₁₀Co₉₀/rGO (34.7 mW cm⁻²) anode catalysts, respectively. These results indicate that the competency of operating procedure for assembling nickel alloys electrodes can improve the activity of the prepared catalysts for BOR considerably.     

Preparation of Pd/ZnO/Ni hierarchical porous array film with enhanced electrocatalytic activity for methanol oxidation

In this study, we successfully synthesized a Pd/ZnO/Ni hierarchical porous array-film catalyst by electrodeposition and magnetron sputtering with the assistance of the monodisperse colloidal sphere template. Structural characterisation indicated that a layer of Pd nanoparticles was uniformly grown on the ZnO/Ni ordered bowl-like micro/nano array film. Electrochemical measurements in alkaline solution demonstrated that the as-grown array film had outstanding electrocatalytic activity for methanol oxidation. The specific activity of the Pd/ZnO/Ni porous array film was up to 130.1 mA cm⁻². The corresponding mass activity (812.7 mA mg⁻¹) was 6 times higher than that of commercial Pd/C catalyst (134.8 mA mg⁻¹), and the stability was also much better than the commercial one. These excellent electrochemical properties can be attributed to the unique hierarchical porous structure, which offers a high specific surface area for the methanol reaction, and ZnO intermediate layer, which effectively removes the poisoning species from the Pd sites through the strong oxidative hydroxyl radicals.