| Direct hydrogen peroxide fuel cell?DPPFC?is a new type of liquid fuel cell that uses both H2O2 as a fuel and H2O2 as an oxidant,so that the fuel cells can be operated in anaerobic environment?such as space and underwater power?.In this paper,the catalytic electrode of DPPFC was studied.A series of catalytic electrodes were designed and prepared.The activity and stability of the electrooxidation?cathodic reaction?and the electrooxidation?anodic reaction?of H2O2 in acid were studied.The cell performance of DPPFC with these electrodes as anode and cathode were also studied.Ni-foam supporting NiCo2O4 nanoelectrode was prepared by a facile template-free method and the electrocatalytic properties of the NiCo2O4/Ni-foam was studied.The results of XRD indicated that the NiCo2O4/Ni-foam electrode is a nanowire array structure with spinel structure,the single nanowire was uniform,with a length of about 800900 nm and a diameter of about 50100 nm,consisting of a number of nanoparticles with a diameter of about 1015 nm,and a large number of irregular pores with an average size of about 27nm were on the nanowires.Electrochemical experiments had proved that prepared NiCo2O4/Ni-foam nanowire array electrode exhibited high electrocatalytic activity and stability for electroreduction and electrooxidation of H2O2.At-0.4 V,the reduction current density can be 190 mA?cm-2in the solution of 3.0 mol?L-1KOH+0.4 mol?L-1H2O2,larger than 79 mA?cm-22 of electrode coated with NiCo2O4 powder,the oxidation current density can be 462 mA?cm-22 at 0.3 V.The cell performance of DPPFC with porous NiCo2O4/Ni-foam as the anode and Pd/CFC electrodes as the cathode was assembled and investigated.At 20°C,the DPPFC displayed a stable OCP of 0.86 V and the maximum output power of the battery was 20.1 mW?cm-2,higher than the previously reported electrode(14 mW?cm-2).Nickel ferric ferrocyanide?NiFeHCF?nanoparticles catalyst for bimetallic Prussian blue were successfully synthesized by a co-precipitation method,and then the nanoparticles were coated on the surface of carbon cloth to prepare NiFeHCF/CFC nanoelectrode.Results tested with TEM and XRD claimed that the prepared NiFeHCF particles were face centered cubic structures with great crystallinity,and the mean particle size was about 2.57 nm,porously and evenly distributed on the surface of the carbon cloth substrate.At 0.1 V,the reduction current density of H2O2 can be 115 mA?cm-2,larger than 40 mA?cm-22 of the previously reported Au electrode.A single DPPFC cell was assembled by using NiFeHCF(n Fe:nNi=1:1,7mg?cm-2)/CFC as the cathode and Ni/Ni-foam as the anode,respectively.The DPPFC single cell displayed a stable OCP of 1.09 V and a peak power density of 36 mW?cm-22 at 20°C,which was 2.5 times higher than 14.3 mW?cm-22 of a DPPFC employed with Pd/CFC cathode.At 40°C,the peak power density of DPPFC was 63 mW?cm-2.Results illustrated that NiFeHCF nanoparticles can be conceived as a promising cost-effective and scalable alternative for noble metal for the reason of its facile synthesis,low cost,especially high property for H2O2 reduction.Nickel cobalt ferricyanide catalyst?NiCoHCF/CFC?nanoelectrodes for bimetallic prussian blue with carbon cloth as the substrate were successfully synthesized by a co-precipitation method.Results tested with SEM claimed that the mean particle size of the as-prepared samples was about 2.44 nm,the specific surface area was 22.1 m2?g-1,with face centered cubic structures of great crystallinity.Their catalytic ability for H2O2electroreduction was evaluated by cycle voltammetry,linear sweep voltammetry and chronoamperometry,proved that the as-prepared NiCoHCF(nNi:nCo=1:1,6 mg?cm-2)/CFC had a high catalytic activity and great stability toward to H2O2 electroreduction.At-0.2 V,the reduction current density was 200 mA?cm-2.A single DPPFC assembled by using porous NiCoHCF(nNi:nCo=1:1,6 mg?cm-2)/CFC as the cathode and Ni/Ni-foam as the anode,respectively,the OCP was 1.07 V and the peak power density was 43 mW?cm-22 at 20°C.Nickel ferric cobalt ferrocyanide catalyst?FeNiCoHCF/CFC?electrodes for trimetal Prussian blue on the carbon cloth substrate were successfully synthesized by a co-precipitation method.The results tested by SEM and XRD claimed that their mean particle sizes were 15.05 nm,10.39 nm,12.8 nm and 16.62 nm,when the mole ratio of nFe:nNi:nCoo was1:1:1,2:1:1,1:2:1 and 1:1:2 with face centered cubic structures of great crystallinity.Their catalytic ability for H2O2 electroreduction related to the relative content of Fe,Ni and Co was evaluated proving that the catalytic activity for H2O2 electroreduction increased with the increasing relative content of Ni.The as-prepared FeNiCoHCF(nFe:nNi:nCo=1:2:1,6mg?cm-2)/CFC nanoelectrode showed the best electrocatalytic properties.At-0.2 V,the current density of H2O2 electroreduction was 209 mA?cm-2.At 20°C,a DPPFC assembled by using porous Ni/Ni-foam as the anode and FeNiCoHCF(nFe:nNi:nCo=1:2:1,6 mg?cm-2)/CFC as the cathode respectively,displayed a stable OCP of 1.06 V and a peak power density of 43.4mW?cm-2,the corresponding current density was 100.4 mA?cm-2,and the voltage was 0.42 V,indicated the cost of fuel cell redused and the performance improved with FeNiCoHCF/CFC as the cathode. |
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