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A three-dimensional (3D) catalyst electrode of Co3O4 nanosheets in situ formed on reduced graphene oxide modified Ni foam (Co3O4/rGO@Ni foam) for H2O2 electroreduction is prepared by a two-step hydrothermal method. In the first step, graphene oxide sheets are reduced and formed on the skeleton of Ni foam and Co3O4 nanosheets are synthesized intermixed with the rGO sheets through the second step. The Co3O4 nanosheets are made up of plentiful nanoparticles and there are many nanoholes among these nanoparticles which are beneficial for the sufficient contact between H2O2 and the catalyst. The morphology and phase composition of the Co3O4/rGO@Ni foam electrode are studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrocatalytic activity of the as-prepared electrode is investigated by cyclic voltammetry (CV) and chronoamperometry (CA). From the results, it can be seen that in 2 mol L−1 NaOH and 0.5 mol L−1 H2O2, the reduction current density of H2O2 on the Co3O4/rGO@Ni foam electrode is 450 mA cm−2 at −0.8 V which is much higher than that on Co3O4 directly supported on Ni foam. This obvious increase of the current density can be attributed to the increase of the surface area of the electrode after the addition of rGO. Also, the interpenetration of rGO and Co3O4 nanosheets improves the electron and ion transport ability of the electrode which leads to a good electrocatalytic activity and stability of the Co3O4/rGO@Ni foam electrode. [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]

Fe-N-C catalysts were prepared through metal-assisted polymerization method. Effects of carbon treatment, Fe loading, nitrogen source, and calcination temperature on the catalytic performance of the Fe-N-C for HO electroreduction were measured by voltammetry and chronoamperometry. The Fe-N-C catalyst shows optimal performance when prepared with pretreated active carbon, 0.2 wt.% Fe, paranitroaniline (4-NA) and one-time calcination. The Fe-N-C catalyst displayed good performance and stability for electroreduction of HO in alkaline solution. An Al-HO semi-fuel cell was set up with Fe-N-C catalyst as cathode and Al as anode. The cell exhibits an open-circuit voltage of 1.3 V and its power density reached 51.4 mW cm at 65 mA cm. [ABSTRACT FROM AUTHOR]

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: 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]

The rational design of efficient electrocatalysts for hydrogen peroxide electroreduction is essential to improve the performance of direct hydrogen peroxide fuel cells. In this study, we synthesized a Co 4 N/CoNC with a heterogeneous interface grown directly on nickel foam (NF) substrates as a highly active electrocatalyst for hydrogen peroxide (H 2 O 2) electroreduction (HPRR). Benefiting from the integrated three-dimensional structure with sufficient active sites, the high electrical conductivity, and the synergistic effect of the heterogeneous interfaces of Co 4 N and Co–N–C, the electrode provides superior H 2 O 2 electrocatalytic properties, with a current density up to 0.65 A cm−2 at −0.8 V vs. Ag/AgCl, Tafel slope at 34.86 mV dec−1 and low activation energy as 9.65 kJ mol−1 in alkaline medium. Our findings provide insights into the design of efficient H 2 O 2 electrocatalyst design. [Display omitted] • Co 4 N/CoNC heterointerface catalysts synthesized by simple hydrothermal and co-precipitation methods. • The unique structure of Co 4 N/CoNC provides a large exposure of the heterogeneous interface to the reaction environment. • Co 4 N/CoNC exhibit excellent catalytic activity and stability in the electroreduction of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

The electrochemical nitrate reduction reaction (eNO 3 RR) to ammonia (NH 3) is a promising alternative method to the Haber-Bosch process that requires high temperature and pressure. In this contribution, the integrated Co 3 O 4 nanowire arrays on Ni foam (Co 3 O 4 /NF) are reported to exhibit the outstanding performance with a high NH 3 yield rate of 117.01 mg h−1cm−2, a superior NH 3 Faradaic efficiency of 99.28 %, a high effective current density of 1475.71 mA cm−2, and a good operation durability during 40 consecutive recycling tests (40 h) in 1.0 M NaOH (0.1 M NaNO 3). The high-valence metal cations as electron-deficient centers can act as Lewis-acid sites, favorably interacting with the Lewis base NO 3 −, and accordingly boosting the NO 3 − adsorption and activation. Moreover, the in-situ growth array configuration provides the substantial active sites and constructs a fast electron-transport channel, thus facilitating the conversion of NO 3 −-to-NH 3. Density functional theory (DFT) calculations also reveal that the Co atoms as the active sites are preferred to adsorb NO 3 −, implying that the NO 3 − electroreduction dominates the cathodic reaction rather than hydrogen evolution reaction. This study provides a viable method to design integrated electrodes with enhanced eNO 3 RR activity and selectivity, which might have broad prospects in the application of renewable energy. The efficient nitrate-to-ammonium conversion is achieved by the integrated Co 3 O 4 nanowire arrays rich in electron-deficient centers. Benefitted from the massive exposed active sites, improved conductivity and charge transfer efficiency, as well as the abundant Lewis acid sites, Co 3 O 4 nanowire arrays present the brilliant nitrate electroreduction performance, including 117.01 mg h−1 cm−2 NH 3 yield rate and 99.28 % Faradaic efficiency in 1.0 M NaOH with 0.1 M NO 3 −. [Display omitted] • High-valence metal cations are favorable to boost NO 3 − adsorption and activation. • Integrated nanowire arrays configuration can provide massive exposed active sites. • Co 3 O 4 /NF can provide a fast electron-transport channel and excellent conductivity. • Co 3 O 4 /NF presents the considerable activity and stability towards eNO 3 RR process. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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: 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]

Bimetallic oxide CoMn 2 O 4 with nano-peony structure is prepared on Ni foam by a traditional hydrothermal process. Then constant-potential electrodeposition is applied to anchor Pd nanoparticles on CoMn 2 O 4 to form an electrode of Pd nanoparticles modified CoMn 2 O 4 (PCMN electrode) for H 2 O 2 electroreduction. The combination of Pd and CoMn 2 O 4 effectively reduces the dosage of noble metal. Besides, no binder is involved in the preparation which cuts the electrode cost and avoids the poor stability of traditional electrodes produced with binders. Scanning electron microscopy, X-ray diffraction and transmission electron microscopy are operated to investigate the structure and composition of the electrode. And the electrochemical behavior of the electrode is characterized by cyclic voltammetry and chronoamperometry. In 0.7 mol L−1 H 2 O 2 and 3 mol L−1 NaOH, a reduction current density of 580 mA cm−2 (normalized by geometric area) at −0.8 V on the electrode is obtained which reveals large capacity for actual application in H 2 O 2 -based fuel cell. A binder-free electrode of Pd nanoparticles anchored to nano-peony CoMn 2 O 4 was prepared and the synergy effect of Co, Mn and Pd highly improved the catalytic activity toward H 2 O 2 reduction. Unlabelled Image • Pd modified CoMn 2 O 4 electrode with special nano-peony structure was synthesized. • The special nano-peony structure provides more active sites for H 2 O 2 reduction. • The synergy effect of Co, Mn and Pd highly improved the catalytic activity. [ABSTRACT FROM AUTHOR]