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Abstract: The growth of CuO nanosheet arrays on Cu foil was demonstrated. The morphology and structure of the CuO were examined by scanning electron microscopy and X-ray diffraction spectroscopy. The catalytic performance of the obtained CuO/Cu electrode for hydrogen peroxide electroreduction in 3.0moldm−3 KOH was evaluated by means of cyclic voltammetry and chronoamperometry. The CuO/Cu electrode shows an onset potential for H2O2 electroreduction comparable to Co3O4 nanowire arrays grown on Ni foam and around 100mV more negative than precious metal catalysts, such as Pt and Pd, demonstrating its good catalytic activity for H2O2 electroreduction. The stabilized mass current density for H2O2 electroreduction on the CuO/Cu electrode at −0.3V reached about 57% of that on Co3O4 nanowire arrays grown on nickel foam. Compared to conventional fuel cell electrodes fabricated by mixing active materials with conducting agents and polymer binders, this electrode of CuO nanosheet arrays directly grown on Cu has superior mass transport property, which combining with its low-cost and facile preparation, make it a promising electrode for fuel cell using H2O2 as the oxidant. [Copyright &y& Elsevier]

Abstract: Nanowire arrays of mixed oxides of Co and Ni freely standing on Ni foam are prepared by a template-free growth method. The effects of Ni content on the morphology, structure and catalyst performance for oxygen evolution reaction are investigated by scanning electron microscopy, X-ray diffraction spectroscopy and electrochemical techniques including cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. A transformation from nanowire arrays to nanoplate arrays is found with the increase of the atomic ratio of Ni to Co in the preparation solution. The NixCo3−xO4 electrode obtained at 1:1 of Ni:Co in the preparation solution exhibits nanowire array structure and has better catalytic performance for oxygen evolution reaction than other NixCo3−xO4 and Co3O4 electrodes. The catalytic activities of the NixCo3−xO4 and Co3O4 electrodes are correlated with their surface roughness. Superior stability of the NixCo3−xO4 nanowire array electrode is demonstrated by a chronopotentiometric test. The reaction orders with respect to OH− on the NixCo3−xO4 electrode are close to 2 and 1 at low and high overpotentials, respectively. [Copyright &y& Elsevier]

Abstract: Direct carbon fuel cells are promising power sources using solid carbon directly as fuel. Their performances significantly depend on the electrooxidation activity of carbon fuel. Electrooxidation of activated carbon particulates in molten Li2CO3–K2CO3 was investigated by potentiodynamic and potentiostatic method. Results indicated that the electrooxidation performance of activated carbon was significantly enhanced by pre-soaking with Li2CO3–K2CO3 and by treatment with HF, HNO3 and NaOH, respectively. The onset potential negatively shifted by around 100 mV and the current density increased by around 50 mA cm−2 after pre-soaking. The non-oxidant acids (HF) treatments are more effective than oxidant acid (HNO3) and base (NaOH) treatments. HF treated activated carbon exhibited the highest activity among all the samples. The enhancement in electrooxidation performance can be closely correlated with the increase in surface area and porosity caused by acid and base treatments. [Copyright &y& Elsevier]

Abstract: Au/Ni-foam electrodes with three dimensional network structures are prepared by simple spontaneous deposition of nano-sized Au particles onto nickel foam surface in an aqueous solution of AuCl3. Their morphology and catalytic performance for NaBH4 electrooxidation and H2O2 electroreduction in NaOH solution are investigated. Au particles with diameters smaller than 100nm are uniformly deposited on the whole surface of all skeletons of the nickel foam substrate. The onset potential for NaBH4 electrooxidation and H2O2 electroreduction is about −1.2V and −0.1V, respectively. A direct liquid feed alkaline NaBH4–H2O2 fuel cell is constructed using Au/Ni-foam electrode as both the anode and the cathode. The effects of the concentration of NaBH4 and H2O2 and operation temperature on the fuel cell performance are investigated. The fuel cell exhibits an open circuit voltage of about 1.07V and a peak power density of 75mWcm−2 at a current density of 150mAcm−2 and a cell voltage of 0.5V operating on 0.2moldm−3 NaBH4 and 0.5moldm−3 H2O2 at 40°C. [Copyright &y& Elsevier]

The adoption of effective, minimal, and versatile electrocatalysts for water splitting to generate hydrogen fuels is of critical importance. The bulk of newly described materials have considerable onset potential, but their electrocatalytic activity is limited by weak electrical conductivity and a limited range of catalytic sites. The combination of a few precious metals added with transition metal-based compounds is a novel and captivating approach. Herein, cobalt ferrite oxide (Co 2 FeO 4) @ palladium oxide (PdO) nanostructures have been prepared through the combined use of hydrothermal and ultraviolet (UV) irradiation techniques. For hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) kinetics, the modified composition offers a high concentration of active sites, improved electrical conductivity, and stability. The Co, Fe, and Pd ions at the composite system's interface may affect the adsorption energy of reaction intermediates synergistically, enabling the process to continue with less potential. The electrocatalyst Co 2 FeO 4 @PdO demonstrates an excellent bifunctional approach to electrochemical water splitting (EWS) for HER and OER in alkaline medium. As-prepared electrocatalyst shows an overpotential value of 269 and 259 mV for HER and OER at 10 and 20 mA/cm2 current densities respectively. The low charge transfer resistance values such as 72.2 and 62.4 Ω and durability for 48 h has been observed toward HER and OER , support this material as an efficient and durable electrocatalyst for energy conversion systems. [Display omitted] • Effective Cobalt–Iron-Ferrite oxides and Palladium-oxide based bifunctional electrocatalyst. • Promising activity for HER and OER with lower Tafel slope values in the alkaline media. • Longer stability and durability for 20 h. [ABSTRACT FROM AUTHOR]

A binder-free and flexible Au electrode is prepared by spontaneous deposition of Au onto a A4 (A4-paper)-8B (8B pencil)-Ni Film substrate (ABNi) which is assembled by electrodeposition of nanoscale Ni particles on the surface of A4 paper coated by 8B pencil. The morphology and phase structure of the (A4-paper)-8B (8B pencil)-Ni Film-Au (ABNiAu) electrode are characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer and X-ray diffractometer. The catalytic activity of the ABNiAu electrode for NaBH 4 electrooxidation is investigated by means of cyclic voltammetry and chronoamperometry. The electrode exhibits a high electric conductivity and the activity substance attaches to the surface of paper substrate tightly and does not fall off at all and the nanoscale Ni and Ni Au alloy enhance the broken of the B H bond in the BH 4 − , all of which lead to a high catalytic activity for NaBH 4 electrooxidation. The oxidation current density reaches 300 mA cm −2 in 1 mol dm −3 NaOH and 0.1 mol dm −3 NaBH 4 at −0.2 V. The exchanged electrons (n) is 6.0 (8.0 in theory), which indicates that the ABNiAu electrode has much higher utilization efficiency of the fuel than our reported LaNi 5 /Pd (n = 4) electrode. [ABSTRACT FROM AUTHOR]

Development of efficient, low cost and multifunctional electrocatalysts for water splitting to harvest hydrogen fuels is a challenging task, but the combination of carbon materials with transition metal-based compounds is providing a unique and attractive strategy. Herein, composite systems based on cobalt ferrite oxide-reduced graphene oxide (Co 2 FeO 4) @(rGO) using simultaneous hydrothermal and chemical reduction methods have been prepared. The proposed study eliminates one step associated with the conversion of GO into rGO as it uses direct GO during the synthesis of cobalt ferrite oxide, consequently rGO based hybrid system is achieved in-situ significantly, the optimized Co 2 FeO 4 @rGO composite has revealed an outstanding multifunctional applications related to both oxygen evolution reaction (OER) and hydrogen counterpart (HER). Various metal oxidation states and oxygen vacancies at the surface of Co 2 FeO 4 @rGO composites guided the multifunctional surface properties. The optimized Co 2 FeO 4 @rGO composite presents excellent multifunctional properties with onset potential of 0.60 V for ORR, an overpotential of 240 mV at a 20 mAcm−2 for OER and 320 mV at a 10 mAcm−2 for HER respectively. Results revealed that these multifunctional properties of the optimized Co 2 FeO 4 @ rGO composite are associated with high electrical conductivity, high density of active sites, crystal defects, oxygen vacancies, and favorable electronic structure arisinng from the substitution of Fe for Co atoms in binary spinel oxide phase. These surface features synergistically uplifted the electrocatalytic properties of Co 2 FeO 4 @rGO composites. The multifunctional properties of the Co 2 FeO 4 @ rGO composite could be of high interest for its use in a wide range of applications in sustainable and renewable energy fields. Illustration of multifunctional surface properties of Co 2 FeO 4 @rGO composite. [Display omitted] • In situ rGO and cobalt ferrite oxide (Co 2 FeO 4 @rGO) composite is prepared. • The synthesized composite exhibited tri-functional water catalysis. • Composite shows an overpotential of 240 mV at a 20 mAcm−2 for OER. • A long term durability of 48 h was also demonstrated by composite material. [ABSTRACT FROM AUTHOR]

Integrating transition metal complexes with carbon-based materials, especially graphene, is a useful strategy for synthesizing effective hydrogen evolution catalysts. Herein, we report a design of hollow hexagonal NiSe–Ni 3 Se 2 nanosheets grown on reduced graphene oxide (NiSe–Ni 3 Se 2 /rGO) by a simple hydrothermal method as an effective catalyst for hydrogen evolution reaction (HER) in the full pH range. In 0.5 M H 2 SO 4 , the NiSe–Ni 3 Se 2 /rGO possesses 112 mV to achieve 10 mA cm−2 and a small Tafel slope (61 mV dec−1). In 1.0 M PBS and 1.0 M KOH, the overpotentials are 261 and 188 mV at 10 mA cm−2, and Tafel slopes are 103 and 92 mV dec−1, respectively. Meanwhile, it owns good cycle stability and durability over 20 h in the whole pH range (0-14). In all solutions, the HER performance of NiSe–Ni 3 Se 2 /rGO is better than that of NiSe–Ni 3 Se 2. This is because the rGO substrate accelerates the electron transfer and improves the electrical conductivity, increasing HER activity of catalyst. • The hollow hexagonal NiSe-Ni3Se2 nanosheets uniformly decorate the rGO. • The hollow structure exposes more active sites and transport pathways. • The hybrid material exhibits superior performance for HER in all pH media. • The stability of the composite is good under a variety of pH conditions. [ABSTRACT FROM AUTHOR]

The highly porous electrode of a crisscrossed CoNi nanosheets array grown on reduced graphene oxide decorated Ni foam (CoNi/rGO@Ni foam) is fabricated through a facile dip and dry method followed by electroreduction and electrodeposition methods. The phase composition and morphology of the electrode are characterized by XRD, SEM, TEM, and EDS. In single electrode tests, CoNi/rGO@Ni foam electrode displays an excellent catalytic performance (330 mA cm−2 at 0.6 V) and stability towards urea electrooxidation when comparing to Ni foam and CoNi nanosheets modified Ni foam (CoNi@Ni foam) electrode. Besides, a low initial oxidation potential of urea electro-oxidation to 0.14 V is achieved on the CoNi/rGO@Ni foam electrode. The introducing of rGO to the electrode greatly reduced the reaction activation energy from 14.47 to 10.35 kJ mol−1. Besides, large active surface area (261.67 cm2) is also obtained from the electrode. The CoNi/rGO@Ni foam anode exhibits a maximum power density of 12.58 mW cm−2 in direct urea-hydrogen peroxide fuel cell tests. Excellent performance shows in single electrode tests and fuel cell tests suggest that addition of rGO to the electrode is an easy and feasible method to enhance the performance of the catalyst. • Highly porous electrode: crisscrossed nanosheets array grows on rGO modified Ni foam. • The influence of rGO on the catalytic performance of the electrode was researched. • Low initial oxidation potential towards urea electro-oxidation was obtained. • Achieved an excellent performance and stability when practical use in DUHPFC. [ABSTRACT FROM AUTHOR]

Seeking the efficient and robust electrocatalysts necessarily enhances performance of hydrogen evolution reaction (HER). Increasing the surface active sites is a means to improve the performance. Herein, we use the Ni 0·85 Se anchored on reduction of graphene oxide (Ni 0·85 Se/rGO) hybrid material skillfully established by one-step facile hydrothermal method as a robust and stable electrocatalyst applying to hydrogen evolution reaction (HER). In terms of morphology, Ni 0·85 Se nanospheres composed of many nanosheets are uniformly distributed on the graphene sheet layer. We also detailedly analyze its properties. Based on the interaction between Ni 0·85 Se and rGO, and the roles of graphene are as a substrate to heighten conductivity, possesses more active surface area by limiting growth of Ni 0·85 Se, and increases dispersion for exposing more active surface area and enlarge ion/electron transfer rate. In HER, the Ni 0·85 Se/rGO catalyst displays the overpotential of 128 mV with a common current density of 10 mA cm−2, a small Tafel slope of 91 mV dec−1, an extremely low onset potential of 37 mV, outstanding stability that a high current retention of 97.7% after 1000 cycles and well long-term stability for 18 h, outperforming the capability of Ni 0·85 Se nanospheres in alkaline solution for HER. The above results indicate that the Ni 0·85 Se/rGO hybrid material is a good HER ability and non-noble metal electrocatalyst has potential value in HER. • The Ni 0.85 Se nanospheres uniformly decorate the rGO sheets. • The Ni 0.85 Se/rGO electrocatalyst possesses more active surface area. • The stability of the composites can reach 97.7%. • The hybrid material exhibits superior performance for HER. [ABSTRACT FROM AUTHOR]

Herein, the vertical thin nickel–iron layered double hydroxide nanosheets grown on the hills-like nickel framework (NiFe LDH/Ni@NF) are employed for the oxygen evolution reaction (OER), securing at the low overpotentials of 197 and 270 mV to obtain the current densities of 20 and 100 mA cm−2, respectively, with a Tafel slope of 73.34 mV dec−1. The electrodeposited nickel film induces the NiFe LDH nanosheets grow vertically and thinly. As well, the nickel abundant interfaces and inner space makes this catalyst effective for OER. It was further served as the OER electrode in a water splitting system coupled the Pt/C cathode, and a cell voltage was at 1.52 and 1.67 V to achieve the current density of 10 mA cm−2 and 50 mA cm−2. In addition, the water electrolyzer can suffer a long time of 24 h at 50 mA cm−2, showing the feasibility in a practical unbiased alkaline water splitting system. • The vertical thin Ni 4 Fe 1 LDH-16h was prepared on the hills-like nickel framework. • The crosslinked nanosheets can offer amounts of active sites for OER. • It achieves a low overpotential of 197 mV to drive 20 mA cm−2 for OER. • The assembled electrolyzer exhibits enhanced performance. [ABSTRACT FROM AUTHOR]

In this paper, we report the three-dimensional self-supported CoMoO 4 nanosheet clusters on the nickel foam (denoted as CoMoO 4 /NF) by a facile hydrothermal-calcination method for efficient hydrogen generation. As a result, the freestanding CoMoO 4 electrode exhibits an efficient electrochemical activity towards hydrogen evolution reaction, showing overpotentials as low as 68 and 178 mV at current densities of 10 and 100 mA cm−2 in the alkaline condition (1 M KOH), respectively, a Tafel slope value of 82 mV per decade. Moreover, the electrode exhibits remarkable electrochemical durability for 1000 cycles. Significantly, the water splitting electrolyzer assembled with CoMoO 4 /NF || NiFe LDH/NF (the nickel iron layered double hydroxide supported on the nickel foam) system achieved 20 mA cm−2 at 1.63 V, showing the CoMoO 4 /NF is promising for practical water splitting applications. • The low-cost and effective transition metal oxide of CoMoO 4 was adopted for hydrogen generation. • The open nanostructure can facilitate permeating electrolyte as well as releasing hydrogen molecules. • The crosslinked nanosheet clusters can offer amounts of active sites for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Abstract At present, there is an urgent need for plentiful non-noble metal catalyst to substitute for valuableness platinum based metal catalyst in electrochemical water splitting. Here, we fabricated a three-demensional (3D) Ni Co NiCo 2 O 4 nanosheets electrocatalyst that directly grew on Ni foam firstly and then were reduced in 0.1 mol dm−3 sodium borohydride solution. This electrode exhibited high activity in 1.0 mol dm−3 KOH solution with an onset potential of ∼40 mV and a tafel slope of 77 mV dec−1. Furthermore, the Ni Co NiCo 2 O 4 /NF electrode showed a splendid durability during long-playing electrochemical test. Our work may provide an inexpensive, easy-to-obtain and excellent catalyst candidate for future electrolytic water research and industry studies that may involve hydrogen applications in the future. Highlights • The Ni Co NiCo 2 O 4 /NF is an inexpensive, easy-to-obtain and excellent electrode. • When the current density up to 10 mA cm−2 requires an overpotential 125 mV. • Metallic Ni and Co core enhance the electrode activity. [ABSTRACT FROM AUTHOR]

Porous Ni 2 P nanoflower supported on nickel foam (Ni 2 P@Ni foam) electrodes are synthesized via a simple hydrothermal growth strategy accompanied with further phosphating treatment. The prepared electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). Electro-catalytic performances towards urea electro-oxidation are tested by cyclic voltammetry (CV), chronoamperometry (CA) coupled with electrochemical impedance spectroscopy (EIS). By phosphating Ni(OH) 2 precursor, the final obtained Ni 2 P@Ni foam electrode presents a porous Ni 2 P nanoflower structure within abundant porosity, and so exposes a large amount of electro-catalytic active sites and electronic transmission channels to accelerate the interfacial reaction. Compared with Ni(OH) 2 @Ni foam precursor, the Ni 2 P@Ni foam catalyst exhibits more excellent electro-catalytic activity as well as lower onset oxidation potential. Remarkably, the Ni 2 P@Ni foam catalyst reaches a peak current density of 750 mA cm −2 with an onset oxidation potential of 0.24 V (vs. Ag/AgCl) accompanied by an excellent stability in 0.60 M urea with 5.00 M KOH solutions. Benefiting from the unique porous nanosheet structure, the as-synthesized Ni 2 P@Ni foam catalyst performs a highly enhanced catalytic behavior for alkaline urea electro-oxidation, indicating that the material can be hopefully applied in direct urea fuel cells. [ABSTRACT FROM AUTHOR]

Direct peroxide-peroxide fuel cell (DPPFC) employing with H 2 O 2 both as the fuel and oxidant is an attractive fuel cell due to its no intermediates, easy handling, low toxicity and expense. However, the major gap of DPPFC is the cathode performance as a result of the slow reaction kinetics of H 2 O 2 electro-reduction and thus the target issue is to design cathode catalysts with high performance and low cost. Herein, different with using noble metal of state-of-the-art, we have successfully synthesized ultra-fine Ni Fe ferrocyanide (NiFeHCF) nanoparticles (the mean particles size is 2.5 nm) through a co-precipitation method, which is used as the cathode catalyst towards H 2 O 2 reduction in acidic medium. The current density of H 2 O 2 reduction on the resultant NiFeHCF electrode after the 1800 s test period at −0.1, 0 and 0.1 V are 121, 93 and 76 mA cm 2 , respectively. Meanwhile, a single two-compartment DPPFC cell with NiFeHCF nanoparticles as the cathode and Ni/Ni foam as the anode is assembled and displayed a stable OCP of 1.09 V and a peak power density of 36 mW cm −2 at 20 °C, which is much higher than that of a DPPFC employed with Pd nano-catalyst as cathode. [ABSTRACT FROM AUTHOR]

Thorn-like Ni@TiC NAs and flake-like Co@TiC NAs electrodes without any conductive agent and binder are simply fabricated by the potentiostatic electrodeposition of Ni and Co catalysts on the TiC nanowire arrays (NAs). The electrocatalytic activity of H 2 O 2 oxidation on the Ni@TiC NAs electrodes is better than that on the Co@TiC NAs electrodes. The Ni@TiC NAs electrodes demonstrate a rough surface and have many nano-needles on the rod edges, which assures the high utilized efficiency of Ni catalysts. These particular three-dimensional structures may be very suitable for H 2 O 2 electrooxidation. The anodic current of Ni@TiC NAs anode reaches 0.32 A cm −2 at 0.3 V in 1.0 M H 2 O 2 + 4 M KOH solution. The DPFCs employing Ni@TiC NAs anodes display the peak power density of 30.2 mW cm −2 and open circuit voltage of 0.90 V at 85.1 mA cm −2 with desirable cell stability at 10 mL min −1 flow rate and 20 °C, which is much higher than those previously reported. [ABSTRACT FROM AUTHOR]

Recently, direct borohydride fuel cell (DBFC) has been considering as a promising energy conversion devices. During the development of DBFC, reducing the use of noble metals and increasing the anode performance are the hot topic in recent researches. In this article, reduced graphene oxide nanosheets deposit on C@TiC coaxial nanowire array (rGO-C@TiC) by means of a combine method of chemical vapor deposition and electrodeposition is chosen as 3D current collector for Pd nanoparticles deposition. The morphology and crystal structure of the as-obtained 3D electrode is checked with FESEM, TEM, EDS, and XRD. Results claim that the as-prepared 3D electrode exhibits a mushroom-like structure with the mean diameter size of Pd is 5.32 nm. Their catalytic ability for NaBH 4 electro-oxidation is evaluated in a three electrode system by using the method of cycle voltammetry and chronoamperometry, proving that the 3D Pd-rGO-C@TiC electrode has a higher catalytic performance. The oxidation current density of 1.35 A cm −2 mg −1 Pd is achieved at −0.6 V. Furthermore, a direct borohydride-hydrogen peroxide fuel cell (DBHPFC) is assembled by using the as-prepared Pd-rGO-C@TiC electrode and a Pd/CFC electrode as anode and cathode catalyst, respectively, and a maximum power density of 68.5 mW cm −2 is obtained. In addition, the assembled DBHPFC shows excellent higher performance based on the mass activity basis (1427.1 W g −1 ) among those reported literatures, indicating that our Pd-rGO-C@TiC could be acted as a promising cost-effective and ponderable alternative catalyst for NaBH 4 electrooxidation. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) reduced graphene networks (RGN) were successfully fabricated on Ni foam without any conductive agents and polymer binders by dipping commercial Ni foam into graphene oxide (GO) suspension and subsequent a electroreduction process in a buffer solution. Au nanoparticles were then deposited on the RGN through an electrodeposition process to form a novel reduced graphene networks-Au (RGNA) electrode. The morphology and phase structure of the RGNA electrode are characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction spectrometer. The NaBH 4 electrooxidation performance on the RGNA electrode is investigated by means of cyclic voltammetry and chronoamperometry. The RGNA electrode owns special hierarchical porous structure, rapid electron and ion transport, and large electroactive surface area due to the intrinsic electronic conductivity, mesoporous nature of graphene. The RGNA electrode exhibits a good stability during the electrochemical process and the oxidation current density at RGNA electrode reached 500 mA cm −2 at 0 V in the solution containing 0.1 mol dm −3 NaBH 4 and 2 mol dm −3 NaOH, which is higher than that at bare Au–Ni foam without graphene. The excellent structural stability and high catalytic performance for NaBH 4 electrooxidation make the RGNA a promising material for future energy systems. [ABSTRACT FROM AUTHOR]

Abstract: Flexible and wearable cobalt electrode with a unique three-dimensional hierarchical-network structure is prepared by electrodeposition of spherical Co particles onto multiwalled carbon nanotubes (MWNTs) which are assembled on the skeleton of cosmetic cotton (CC). The morphology and phase structure of the cobalt–multiwalled carbon nanotubes–cosmetic cotton (Co–MWNTs–CC) electrode are characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction spectrometer. The NaBH4 electrooxidation performance on the Co–MWNTs–CC electrode is investigated by means of cyclic voltammetry and chronoamperometry. Results show that the Co–MWNTs–CC electrode exhibits remarkably high catalytic activity and good stability for NaBH4 electrooxidation. The oxidation current density reaches as high as 170 mA cm−2 at −0.7 V in 1.0 mol dm−3 NaOH and 0.1 mol dm−3 NaBH4, which is higher than the most-related previous results. [Copyright &y& Elsevier]

Abstract: Activation of the MmNi4.03Co0.42Mn0.31Al0.24 hydrogen storage alloy electrode is performed by immersing the electrode in a solution containing 6.0moldm−3 NaOH and 0.1 mol dm−3 NaBH4. The effects of activation on the electrocatalytic activity of the electrode for NaBH4 oxidation are investigated by cyclic voltammetry and chronoamperometry. Immersion activation greatly improves the electrocatalytic activity of the alloy electrode. Hydrogen was absorbed in the alloy during the immersion activation treatment and its electrooxidation is responsible for the high initial oxidation current. The stabilized current mainly results from the direct oxidation starting from the borohydride species. The effects of activation on structure and surface chemistry of the alloy are also discussed. [Copyright &y& Elsevier]