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A novel three-dimensional (3D) porous nickel-cobalt (Ni-Co) film on nickel foam is successfully prepared and further used as an efficient anode for direct urea-hydrogen peroxide fuel cell (DUHPFC). By varying the cobalt/nickel mole ratios into 0%, 20%, 50%, 80% and 100%, the optimized Ni-Co/Ni foam anode with a ratio of 80% is obtained in terms of the best cell performance among five anodes. Effects of the KOH and urea concentrations, the flow rate and operation temperature on the fuel cell performance are investigated. Results show DUHPFC with the 3D Ni-Co/Ni foam anode exhibits a higher performance than those reported direct urea fuel cells. The cell gives an open circuit voltage of 0.83 V and a peak power density as high as 17.4 and 31.5 mW cm −2 at 20 °C and 70 °C, respectively, when operating on 7.0 mol L −1 KOH and 0.5 mol L −1 urea as the fuel at a flow rate of 15 mL min −1 . Besides, when the human urine is directly fed as the fuel, direct urine-hydrogen peroxide fuel cell reaches a maximum power density of 7.5 mW cm −2 with an open circuit voltage of 0.80 V at 20 °C, showing a good application prospect in wastewater treatment. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogen peroxide (H2O2) replaced oxygen (O2) as oxidant has been widely investigated due to its faster reduction kinetics, easier storage and handling than gaseous oxygen. The main challenge of using H2O2 as oxidant is the chemical decomposition. In this article, by using different C2H5OH/H2O volume ratio as the solvent, Co3O4 with different morphologies (nanosheet, nanowire, ultrafine nanowire net, nanobelts, and honeycomb-like) direct growth on Ni foam are synthesized via a simple solvothermal method for the first time. Results show that the introduction of ethanol could obviously improve the catalytic performance toward H2O2 electroreduction. The sample prepared in the solution with the C2H5OH/H2O volume ratio of 1:2 shows the best catalytic performance among the five samples and a current density of 0.214 A cm−2 is observed in 3.0 mol L−1 KOH + 0.5 mol L−1 H2O2 at −0.4 V (vs. Ag/AgCl KCl), which is much larger than that on the other metal oxides reported previously, almost comparable with the precious metals. This electrode of Co3O4 directly grown on Ni foam 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: 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: The open circuit potentials (OCPs) of H2O2 at Pt, Pd, Au, and glassy carbon electrodes are measured in H2SO4 and NaOH electrolyte solutions. Effects of concentration of H+, OH− and H2O2 as well as temperature on the OCP of H2O2 are investigated. The OCP of H2O2 is much lower than its theoretical reduction potential in both acidic and basic medium. The OCP is actually a mixed potential of H2O2 electroreduction and electrooxidation simultaneously occurring at electrode surfaces and it is more close to the equilibrium potential of H2O2 electrooxidation rather than electroreduction. The OCP of H2O2 is around 0.77–0.80V at [H+]=[H2O2]=1.0moldm−3 in H2SO4 solution and is about 0–0.06V at [OH−]=[H2O2]=1.0moldm−3 in NaOH at 298K on Pt, Pd, Au and GC electrodes. The OCP of H2O2 is independent of H2O2 concentration within the range of 0.01 to 1.0moldm−3. It increases approximately linearly with the logarithm of H+ concentration from 0.02 to 2.0moldm−3, decreases with the logarithm of OH− concentration from 0.01 to 1.0moldm−3 and decreases with increase of temperature from 278K to 333K. The linear equations were presented and discussed. [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]

Abstract: A high performance alkaline direct borohydride–hydrogen peroxide fuel cell with Pt–Ru catalyzed nickel foam as anode and Pd–Ir catalyzed nickel foam as cathode is reported. The electrodes were prepared by electrodeposition of the catalyst components on nickel foam. Their morphology and composition were analyzed by SEM–EDX. The effects of concentrations of NaBH4 and H2O2 as well as operation temperature on the cell performance were investigated. The cell exhibited an open circuit voltage of about 1.0V and a peak power density of 198mWcm−2 at a current density of 397mAcm−2 and a cell voltage of 0.5V using 0.2moldm−3 NaBH4 as fuel and 0.4moldm−3 H2O2 as oxidant operating at room temperature. Electrooxidation of NaBH4 on Pt–Ru nanoparticles was studied using a rotating disk electrode and complete 8e− oxidation was observed in 2moldm−3 NaOH solution containing 0.01moldm−3 NaBH4. [Copyright &y& Elsevier]

Abstract: Pd nanoparticles were immobilized on Au disk electrode and kinetics of hydrogen peroxide electroreduction on the Pd electrode in 0.1M H2SO4 solution was investigated using a rotating disk electrode method. The phase and particle size of palladium were characterized by XRD measurements. The morphology of Pd on Au was examined using SEM. We found that the hydrogen peroxide reduction on Pd nanoparticles proceeds via a two-electron process. The reaction order is one with respect to hydrogen peroxide. An apparent activation energy of 55kJmol−1 was calculated from exchange currents at different temperature. The lower activation energy and higher exchange current density demonstrated that hydrogen peroxide reduction has a faster kinetics than oxygen reduction. Electrolyte anions significantly affect hydrogen peroxide reduction activity, and the activity decreases in the order > >Cl−, which is consistent with the increasing adsorption bond strength of the anions. [Copyright &y& Elsevier]

Abstract: Spinel structure Co3O4 nanoparticles with an average diameter of around 17nm were prepared and evaluated as electrocatalysts for H2O2 reduction. Results revealed that Co3O4 exhibits considerable activity and good stability for electrocatalytic reduction of H2O2 in 3M NaOH solution. The reduction occurs mainly via the direct pathway when H2O2 concentration is lower than 0.5M. An Al-H2O2 semi fuel cell using Co3O4 as cathode catalyst was constructed and tested at room temperature. The fuel cell displayed an open circuit voltage of 1.45V and a peak power density of 190mWcm−2 at a current density of 255mAcm−2 operating with a catholyte containing 1.5M H2O2. This study demonstrated that Co3O4 nanoparticles are promising cathode catalysts, in place of precious metals, for fuel cells using H2O2 as oxidant. [Copyright &y& Elsevier]

A novel electrode of PdCu nanoparticles modified free-standing reduced graphene oxide (rGO) framework (PdCu@rGOF) is fabricated via electrodeposition and chemical reduction and employed to the direct sodium borohydride-hydrogen peroxide fuel cell (DBHPFC). The resultant catalyst reveals excellent catalytic performance towards hydrogen peroxide (H 2 O 2) electroreduction reaction (HPRR) and sodium borohydride (NaBH 4) electrooxidation reaction (BOR) along with low activation energy (E a). Numerically, the PdCu@rGOF electrode delivers an HPRR current density of 455.2 mA cm−2 at 0 V (2 mol L−1 H 2 SO 4 +1.3 mol L−1 H 2 O 2). Additionally, the current density of BOR reaches up to 1065.3 mA cm−2 at 0 V for 2 mol L−1 NaOH and 0.3 mol L−1 NaBH 4. Meanwhile, the mechanism studies show that HPRR and BOR catalyzed by PdCu@rGOF mainly relates 2-electron-transfer process and quasi-8-electron-transfer process, respectively. Subsequently, PdCu@rGOF is assembled into a fuel cell, yielding the optimal power density of 188.9 mW cm−2. The open circuit potential (OCP) of DBHPFC is about 1.70 V at 293.15 K. The superior electrochemical performance of the optimized electrode can be attributed to the distinctive architecture and the strong adsorption and bond-breaking ability of Pd nanoparticles. This work indicates that the as-prepared PdCu@rGOF can be a promising catalyst for DBHPFC. [Display omitted] • A novel 3D through-hole rGOF framework has been successfully prepared. • PdCu@rGOF displays an excellent catalytic performance for HPRR and BOR. • PdCu@rGOF can be applied to both anode and cathode of DBHPFC. • DBHPFC presents high power density and operation stability. [ABSTRACT FROM AUTHOR]

Abstract: The electrochemical performances of magnesium, magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium as the anode of magnesium–hydrogen peroxide semi-fuel cells have been studied by methods of potentiodynamic, potentiostatic and electrochemical impedence measurements. The surface morphologies of magnesium and its alloys have been examined by scanning electron microscopy (SEM). It has been found that magnesium–lithium–aluminum–cerium and magnesium–lithium–aluminum–cerium–yttrium electrodes are less corrosion resistant than that of magnesium electrode in 0.7molL−1 NaCl solution and the corrosion current density decreases with the following order: magnesium

A current collector of reduced graphene oxide modified Ni foam (RN) is synthesized through a handy method of hydrothermal. The sheet-like reduced graphene oxide (rGO) wrapped around the skeleton of Ni foam establishes a unique structure of the current collector with large surface area as well as good electronic conductivity which make a positive effect on the promotion of electrochemical property. Pd is chosen as the catalyst and deposited on the RN substrate in a form of nanoparticle by potentiostatic electro-deposition. Characterization analysis including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and inductive coupled plasma emission spectrometer (ICP) are conducted to investigate the morphology and structure of the final electrode of Pd nanoparticles decorated rGO supported on Ni foam (PRN). In 2 mol L −1 NaOH and 0.5 mol L −1 H 2 O 2 , a current density of 450 mA cm −2 is gained on the PRN electrode which is much larger than that on the electrode of Pd nanoparticles directly deposited on Ni foam (PN). An excellent stability of the PRN electrode is also concluded by the measurements revealing that this material can be potentially and widely applied to direct hydrogen peroxide fuel cell in the near future. [ABSTRACT FROM AUTHOR]

An especial current collector of Ti pillar arrays (Ti Ps) is prepared by a facile hydrothermal etching method. The Ti Ps substrate can be applied in acidic medium for its excellent stability, and the large specific surface area of this substrate is highly beneficial to the contact between electrolyte and catalyst. Pd deposited on the Ti Ps substrate is selected to be the catalyst for H 2 O 2 reduction due to its remarkable electrocatalytic activity and stability. The structure and phase composition of the Pd modified Ti Ps (Pd@Ti Ps) electrode are studied through X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and inductive coupled plasma emission spectrometer (ICP). The electrocatalytic property of the Pd@Ti Ps electrode is studied through cyclic voltammetry (CV) and chronoamperometry (CA). According to the results, the Pd@Ti Ps electrode exhibits a high reduction current density of 220 mA cm −2 at −0.2 V in 2 mol L −1 H 2 SO 4 and 0.5 mol L −1 H 2 O 2 which is greatly larger than that on Pd modified Ti plate (Pd@Ti plate) electrode. The activation energy of H 2 O 2 reduction on this electrode is 19.77 kJ mol −1 . The low activation energy and high electrocatalytic activity indicate that the as-prepared electrode can be applied as a potential cathode for fuel cell. [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]

Petal shaped Co/Co 3 O 4 composite electrocatalyst with a special structure used as a cathode for H 2 O 2 electroreduction is obtained by a route of hydrothermal synthesis and in-situ chemical reduction. The phase composition and microstructure of the electrocatalyst are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical performance of H 2 O 2 electroreduction on the Co/Co 3 O 4 petals (Ps) is explored by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectrometry (EIS). The Co/Co 3 O 4 Ps exhibits a higher conductivity than single Co 3 O 4 , which leads to a better catalytic activity and stability toward H 2 O 2 electroreduction. In a solution of 3 mol L − 1 NaOH and 0.5 mol L − 1 H 2 O 2 , the current density of H 2 O 2 electroreduction on Co/Co 3 O 4 Ps is 440 mA cm − 2 at − 0.8 V, higher than that on Co 3 O 4 , which make the obtained Co/Co 3 O 4 Ps an excellent alternative catalyst for H 2 O 2 fuel cell. [ABSTRACT FROM AUTHOR]

Bimetallic nanoparticles with excellent activity and stability have been widely studied as H 2 O 2 electroreduction catalysts. Hereby, we have successfully found a green fabrication of high-stability Au-Pd nanoparticles directly supported on carbon fiber cloth (Au-Pd NPs/CFC) by using tobacco extract (nicotinamide) as a simple and ecofriendly reducing agent. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction analyses and high angle annular dark field scanning TEM are performed to characterize the morphology, composition and structure of the as-prepared electrode. Results show that alloy nanoparticles prepared with different mole ratios of HAuCl 4 /PdCl 2 mixtures in the wide range of 10–100 nm have a uniform distribution on every carbon fiber, presenting a regular circle shape. The 3D electrode is directly applied as the electrocatalyst for H 2 O 2 reduction in acid solution and does not introduce into any polymer binders. The catalytic performance is investigated by chronoamperometry and voltammetry, exhibiting desired catalytic performance and improved utilization than other representative nanomaterials recently reported. Furthermore, Au-Pd NPs do not aggregate after the whole test due to the effect of in-situ immobilization, showing a great significance for the application in fuel cells. A direct peroxide-peroxide fuel cell (DPPFC) using Au-Pd NPs/CFC cathode with Ni/Ni-foam anode acquires a maximum power density of 22.8 mW cm −2 . Electrochemical stability test through long-term potential cycles ( > 9 h) further confirms the high durability of the electrode. [ABSTRACT FROM AUTHOR]

Nickel-cobalt nanowire arrays (Ni-Co NWAs) electrode is prepared by one-step galvanostatic electrodeposition with a polycarbonate membrane as the template. By adjusting the Co proportion in the Ni and Co bath solution into 10%, the optimal Ni-Co NWAs electrode in terms of relatively lower onset potential and highest current density towards urea electro-oxidation is obtained. Its catalytic performance is investigated by constructing single direct urea/hydrogen peroxide (H 2 O 2 ) fuel cell. Results show that a peak power density of 7.4 mW cm −2 and an open circuit voltage of 0.92 V are achieved at room temperature when 9.0 mol L −1 KOH and 0.33 mol L −1 urea are used as the anolyte, H 2 SO 4 and H 2 O 2 as the catholyte. Additionally, the urea/H 2 O 2 fuel cell also demonstrates excellent stability during short term duration test. [ABSTRACT FROM AUTHOR]

Nanoporous palladium supported on the carbon coated titanium carbide (C@TiC) nanowire arrays (Pd NP/C@TiC) are successfully prepared by a facile chemical vapor deposition of three-dimensional (3D) C@TiC substrate, followed by electrochemical codeposition of Pd–Ni and removal of Ni via dealloying. The structure and morphology of the obtained Pd NP/C@TiC electrodes are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). Cyclic voltammetry (CV), linear sweep voltammetry (LSV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) are used to examine the catalytic performances of the electrodes for H 2 O 2 electroreduction in H 2 SO 4 solution. The Pd NP/C@TiC electrode exhibits a largely effective specific surface area owing to its open nanoporous structure allowing the full utilization of Pd surface active sites. At the potential of 0.2 V in 2.0 mol L −1 H 2 O 2 and 2 mol L −1 H 2 SO 4 solutions, the reduction current density reaches 3.47 A mg −1 , which is significantly higher than the catalytic activity of H 2 O 2 electroreduction achieved previously with precious metals as catalysts. [ABSTRACT FROM AUTHOR]

A novel three-dimensional carbon- and binder-free nickel nanowire arrays (Ni NAs) electrode is successfully fabricated by a facile galvanostatic electrodeposition method using polycarbonate membrane as the template. The Ni NAs electrode achieves a oxidation current density (divided by the electroactive surface areas of Ni) of 25.1 mA cm −2 in 4 mol L −1 KOH and 0.9 mol L −1 H 2 O 2 at 0.2 V (vs. Ag/AgCl) accompanied with a desirable stability, which is significantly higher than the catalytic activity of H 2 O 2 electro-oxidation achieved previously with precious metals as catalysts. The impressive electrocatalytic performance is largely attributed to the superior 3D open structure and high electronic conductivity, which ensures the high utilization of Ni surfaces and makes the electrode have higher electrochemical activity. The apparent activation energy of H 2 O 2 electro-oxidation on the Ni NAs catalyst is 13.59 kJ mol −1 . A direct peroxide–peroxide fuel cell using the Ni NAs as anode exhibits a peak power density of 48.7 mW cm −2 at 20 °C. The electrode displays a great promise as the anode of direct peroxide–peroxide fuel cell due to its low cost, high activity and stability. [ABSTRACT FROM AUTHOR]

In this article, a three-dimensional electrode (Pd-CNT/Ni foam) based on Pd nanoparticles and carbon nanotubes (CNTs) is successfully developed by a simple “dipping and drying” process and a potentiostatic deposition technology for H 2 O 2 reduction in base medium. The composition and structure of Pd-CNT/Ni foam electrode are examined by X-ray diffractometer, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, respectively. The cyclic voltammetry (CV) and chronoamperometry (CA) techniques are applied to determine the electrochemical performance. The electrode exhibits a high catalytic activity for H 2 O 2 electroreduction, and it outperforms Pd/Ni foam electrode without CNT coating. At the reduction potential of −0.8 V, the reduction currents on Pd-CNT/Ni foam electrode can reach 323 mA cm −2 , however, it is only 192 mA cm −2 on Pd/Ni foam electrode, which is increased by 68.2%. The impressive electrocatalytic performance is largely attributed to the superior open structure and high electronic conductivity, which allows the high utilization of Pd surfaces and makes the electrode have higher electrochemical activity. These findings may provide the opportunity on preparing binder-free carbon-supported electrode in the application of fuel cells. [ABSTRACT FROM AUTHOR]

Pt-modified Co nanosheet@carbon sponge (Pt-Co NS@carbon sponge) electrode is synthesized via a facile sponge carbonization method coupled with a direct Co electrodeposition and Pt chemical-deposition. The obtained electrodes are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM). The catalytic performances of H 2 O 2 electroreduction in alkaline medium are investigated by cyclic voltammetry (CV), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS). The Pt-Co NS@carbon sponge electrode exhibits unique nanosheet structure on the three-dimensional (3D) porous network skeleton with a large surface area and displays excellent catalytic performance. The Pt-Co NS@carbon sponge electrode achieves a reduction current density of −1.38 A cm −2 mg −1 in 3.0 mol L −1 KOH and 1.5 mol L −1 H 2 O 2 at −0.50 V (vs. Ag/AgCl) accompanied with a desirable stability, which is significantly higher than the catalytic activity of H 2 O 2 electroreduction achieved previously with precious metals as catalysts. The impressive electrocatalytic performance is largely attributed to the superior 3D open structure and high electronic conductivity, which ensures the full utilization of Pt surfaces and makes the electrode have higher electrochemical activity. Original Pt-Co NS@carbon sponge electordes have a great potential for the application in fuel cells due to its facile preparation, high performance and low cost. [ABSTRACT FROM AUTHOR]

The size-controlled hierarchical textile-like Au nanostructures supported carbon fiber cloth (Au NTs/CFC) is successfully fabricated through a simple low-cost electrochemical route. The electrodes are characterised by scanning electron microscopy equipped with an energy dispersive X-ray spectrometer, transmission electron microscopy and X-ray diffractometer. Without any conducting carbons and polymer binders, the 3D electrode with unique structure is directly used as the electrocatalyst for H 2 O 2 reduction in acid solution and the catalytic performance is evaluated by voltammetry and chronoamperometry. The Au NTs/CFC electrode exhibits much higher catalytic activity and remarkably improved utilization of Au than Au nanoparticles (Au NPs/CFC) prepared by the same method owing to its unique structure. In the solution of 3.0 mol L −1 H 2 SO 4 + 0.1 mol L −1 H 2 O 2 , with the reduction potential of 0 V, the current of −0.72 A cm −2 mg −1 can be obtained on Au NTs/CFC electrode and only a current of −0.09 A cm −2 mg −1 can be achieved on Au NPs/CFC electrode. All these results reveal that the novel Au NTs/CFC electrode exhibits excellent catalytic performance and superior stability for H 2 O 2 electroreduction in acid medium, benefitting from the unique 3D structure which can ensure high utilization of catalyst. [ABSTRACT FROM AUTHOR]

Ni foam supported-NiCo 2 O 4 nanostructures with various morphologies are successfully prepared by a facile template-free method. The synthesis involves the electrodeposition of the bimetallic (Ni, Co) film on Ni foam support. The NiCo 2 O 4 nanostructures are formed by immersing the bimetallic film in an oxalic acid solution, followed by a calcination progress. The control over NiCo 2 O 4 nanostructures with different morphologies is achieved by adjusting the electrodeposition time and immersing time. The electrode is characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction. H 2 O 2 electrooxidation and electroreduction in KOH solution on the NiCo 2 O 4 nanostructures are studied by cyclic voltammetry and chronoamperometry. Results show that NiCo 2 O 4 nanostructures exhibit high performance and superior stability for both H 2 O 2 electrooxidation and electroreduction, resulting from hierarchical porous structure inside their architectures. [ABSTRACT FROM AUTHOR]

Abstract: Non-noble metal film electrode (Co/Ni foam) modified with noble metals (Au and Pd) has been reported. Highly porous Co film is firstly prepared electrochemically on the commercial Ni foam substrate and in turn serves as a hard template and a redox inducer for modification by spontaneous deposition of Au or Pd. The electrodes (Au-modified Co/Ni foam and Pd-modified Co/Ni foam) are characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer, and X-ray diffractometer. The catalytic performance of the 3D porous electrodes is evaluated by voltammetry and chronoamperometry. Results reveal that Au- and Pd-modified Co/Ni foam exhibit excellent catalytic performance and good stability for H2O2 electroreduction compared with Au and Pd particles supported on Ni foam, benefitting from the unique 3D structure which can ensure high utilization of catalyst and quick releases of gas bubbles produced by H2O2 decomposition from the electrode. [Copyright &y& Elsevier]

Carbon fiber cloth (CFC) supported Ni and Co electrodes are prepared by electrodeposition (Ni/CFC and Co/CFC). Their catalytic performance for H2O2 electrooxidation in KOH solution is investigated and compared with Au/CFC electrode. Ni/CFC electrode exhibits higher catalytic activity than Au/CFC and Co/CFC electrodes. The performance of a direct peroxide–peroxide fuel cell (DPPFC) with Ni/CFC anode and Pd/CFC cathode is examined. The cell shows a peak power density of 21.6 mW cm−2 at 20 °C and 53.8 mW cm−2 at 50 °C. The cell performance is improved with the increase of anolyte and catholyte flow rate and operation temperature. Results indicates that the performance of DPPFC with low-cost Ni/CFC anodes is comparable with those using precious metal anodes, e.g., Au/CFC and Pd/CFC. [ABSTRACT FROM AUTHOR]

Abstract: Co3O4 nanowire arrays freely standing on Ti foil (Co3O4/Ti) are prepared via a template-free growth method. Pd nanoparticles are electrochemically deposited by cyclic voltammetry method on Co3O4 nanowires to obtain a nanocomposite electrode (Pd@Co3O4/Ti). The morphology and phase structure of the Pd@Co3O4/Ti electrode are characterized by scanning electron microscope and X-ray diffraction spectrometer. The catalytic activity of H2O2 electroreduction on the Pd@Co3O4/Ti electrode in alkaline medium is evaluated by means of linear scan voltammetry and chronoamperometry. The Pd@Co3O4/Ti electrode exhibits high performance and good stability to H2O2 electroreduction with a current density of 145.8 mA cm−2 at −0.4 V in 3.0 mol dm−3 KOH and 0.4 mol dm−3 H2O2 electrolyte, which outperforms the bare Co3O4 nanowire arrays without Pd doping. [Copyright &y& Elsevier]

Highlights: [•] Pd nanofilm supported on carbon coating TiO2 nanocone arrays (C@TiO2) is reported. [•] Pd NF-C@TiO2 electrode shows an open structure allowing the full utilization of Pd. [•] Pd NF-C@TiO2 electrode exhibits high catalytic activity for H2O2 reduction. [Copyright &y& Elsevier]

Abstract: A novel synthesis of Au–Pd alloy nanoparticles supported on carbon fiber cloth (Au–Pd NPs/CFC) via a potential pulse technique is presented. Different composition stoichiometry of Au–Pd nanoparticles are deposited from the aqueous solutions of HAuCl4/PdCl2 mixtures in molar ratios of 5:1, 2:1, 1:1, 1:2 and 1:5. The electrode is characterized by scanning electron microscopy coupled to energy dispersive X-ray analysis (SEM–EDX), transmission electron microscopy (TEM) and X-ray diffractometer (XRD). H2O2 electroreduction in H2SO4 solution on Au–Pd nanoparticles is studied by linear sweep voltammetry and chronoamperometry. The catalytic performance on different composition stoichiometry of Au–Pd nanoparticles increases with the increase of Pd content. Additionally, the flower-like Au–Pd NPs/CFC electrode exhibits the excellent catalytic properties and good stability to H2O2 electroreduction in acid solution, and it outperforms pure Au or Pd catalyst supported on carbon fiber cloth. [Copyright &y& Elsevier]

Highlights: [•] Dendritic Pd supported on CFC is decorated with Au via potential pulse technique. [•] Au@Pd/CFC electrode shows high catalytic activity for H2O2 reduction and oxidation. [•] DPPFC obtains a much higher performance based on the Au@Pd/CFC electrodes. [ABSTRACT FROM AUTHOR]

Abstract: A high performance direct peroxide–peroxide fuel cell using dendritic Pd supported on carbon fiber cloth as both the anode and the cathode is reported. Effects of the concentration of H2O2, KOH, H2SO4, the operating temperature and the flow rate on the fuel cell performance are investigated. The cell exhibits a much higher performance than those reported in the literature. The open circuit voltage reaches 0.9 V and the peak power density is as high as 14.3 and 58.4 mW cm−2 at 20 °C and 60 °C, respectively, when running on 4.0 mol L−1 KOH + 1.0 mol L−1 H2O2 as the fuel and 2.0 mol L−1 H2SO4 + 2.0 mol L−1 H2O2 as the oxidant, both at a flow rate of 10 mL min−1. [Copyright &y& Elsevier]

Abstract: Dendritic Pd is electrodeposited uniformly on carbon fiber cloth via a potential pulse technique. The electrode is characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffractometer, and it shows a unique open structure allowing the full utilization of Pd surface active sites. H2O2 electrooxidation in KOH solution and electroreduction in H2SO4 solution on the dendritic Pd electrode are studied by linear sweep voltammetry and chronoamperometry. The electrode exhibits a high catalytic performance for both H2O2 electrooxidation and electroreduction, and it outperforms the conventional electrode made with commercial Pd/C powder. KOH and H2SO4 in excess show no improvement to the activity of H2O2 oxidation and reduction, respectively. The overpotential at the same current density for H2O2 electrooxidation in alkaline solution is significantly lower than that for electroreduction in acid medium on the dendritic Pd electrode. [Copyright &y& Elsevier]

Abstract: Perovskite-type series of compounds La1−x Sr x MnO3 are synthesized by a sol–gel method using Chitosan as the gelling agent. Their catalytic activity for hydrogen peroxide electroreduction in 3.0moldm−3 KOH at room temperature is evaluated by means of cyclic voltammetry and chronoamperometry. Effects of annealing temperature and the ratio of La to Sr of La1−x Sr x MnO3 on their catalytic performance are investigated. Among this series of compounds, La0.4Sr0.6MnO3 calcined at 650°C exhibits the highest activity, which is comparable with Co3O4. An aluminum–hydrogen peroxide semi-fuel cell using La0.4Sr0.6MnO3 as cathode catalyst achieves a peak power density of 170mWcm−2 at 170mAcm−2 and 1.0V running on 0.6moldm−3 H2O2. [Copyright &y& Elsevier]