Preparation Of Ni_xCo_y And Pt Nanomaterials And The Study Of Their H₂O₂ Electrocatalytic Behavior

In recent years,the energy consumption is huge and serious environment pollution are caused with the continuous development of society.Direct hydrogen peroxide-hydrogen peroxide fuel cell（DPPFC）is a kind of fuel cell that uses H₂O₂ as fuel and oxidizer at the same time.Since its reaction products are only H₂O and O₂,it can achieve true sustainable environmental protection and pollution-free.The performances of anode electrooxidation reaction and cathode electroreduction reaction of H₂O₂ directly determine the performance of DPPFC,so preparing electrode materials with excellent catalytic activity is the main way to improve the performance of DPPFC.In this paper,Ni_xCo_y and Pt nano electrode materials were prepared to catalyze the electrooxidation and electroreduction of H₂O₂.The CF-1 electrode was prepared by electrochemical oxidation of the foamed copper（CF）substrate,and then CF-2 electrode was prepared by electrochemical reduction.Finally,Ni nano-catalyst was deposited on the surface of CF-2 electrode to prepare CF-2@Ni electrode,and the electro-oxidation performance of the prepared electrode catalyzed by H₂O₂ in alkaline environment was studied.Through physical characterization such as SEM,it was observed that three-dimensional（3D）nano-cone structure was obtained on the surface of CF substrate after electrochemical oxidation treatment,and the Ni nano-catalyst supported on the surface was spherical structure with a diameter of about 200 nm.By comparing the catalytic performance of CF,CF@Ni,CF-1@Ni and CF-2@Ni electrodes in 1.0 mol·dm^-3 Na OH+0.3 mol·dm^-3 H₂O₂solution,it is proved that the prepared CF-2@Ni electrode exhibits the best electrocatalytic activity.The best performance is achieved in a mixed solution of 2.0 mol·dm^-3 Na OH+0.5mol·dm^-3 H₂O₂,and the oxidation current density reaches 710.4 m A?cm^-2 at 0.6 V.According to the Arrhenius equation,the activation energy of the electrode surface reaction is 21.0 k J?mol^-1.And through the CA test of 7000s,the electrode showed good stability.In addition,the reaction mechanism of H₂O₂ on the surface of the CF-2@Ni electrode was studied,which provided a certain guiding significance for the theoretical study of the electrooxidation of H₂O₂catalyzed by Ni catalyst.The CF-2@Ni_xCo_y electrode was prepared by co-depositing Ni-Co nanocomposite catalyst on the surface of CF-2 electrode by changing the ratio of Ni²⁺and Co²⁺in the deposition solution,which was used to catalyze the electrooxidation of H₂O₂ in an alkaline environment.Through SEM and other physical characterization,it was observed that the surface morphology of electrodes prepared with different Ni²⁺and Co²⁺ratios was obviously different.With the increase of Co content,the surface of spherical Ni nanoparticles is no longer smooth and begins to show flower-like structure.Compared with pure Ni catalyst,the prepared Ni-Co nanocomposite catalyst has a larger specific surface area,which can better contact with the reaction solution,and is beneficial to the escape of the gas generated in the reaction process.The catalytic performance of Ni-Co nanocomposite catalyst is obviously better than that of single Ni catalyst and Co catalyst,which indicates that the doping of Co and Ni can show synergistic effect and catalyze the electro-oxidation reaction of H₂O₂ together.In addition,the CF-2@Ni_0.50Co_0.50 electrode was tested by changing the test conditions（Na OH concentration,H₂O₂ concentration）.The electrode showed the best catalytic performance when Na OH concentration was 3.0 mol·dm^-3 and H₂O₂ concentration was 0.3 mol·dm^-3,and the current density reached 962.0 m A·cm^-2 at 0.6 V.The activation energy of electrode surface reaction is19.8 k J·mol^-1.And through the CA test of 7000s,the electrode showed good catalytic stability.In addition,the reaction mechanism of H₂O₂ on the surface of CF-2@Ni_0.50Co_0.50 electrode was studied.the excellent catalytic performance of CF-2@Ni_0.50Co_0.50 electrode is due to the synergistic effect of Ni and Co.The filter paper/graphite-polyaniline@platinum electrode（F/G-PANI@Pt）was prepared by loading graphite layer,polyaniline（PANI）layer and Pt nanoparticles on the surface of filter paper in turn,and it was used to catalyze the electroreduction of H₂O₂ in acidic environment.The PANI loaded on the electrode surface is 3D rod-like structure,which can provide a good foundation for loading Pt nanoparticles.Pt grew uniformly by chemical oxidation-reduction method relying on PANI nanorods,and has large specific surface area.In the mixed solution containing 1.0 mol mol·dm^-3 H₂SO₄+1.5 mol·dm^-3 H₂O₂,the reduction current density on the surface of F/G-PANI@Pt electrode reached-415.10 m A·cm^-2 when the test potential is-0.2 V,.In addition,the reaction mechanism of H₂O₂ on the electrode surface was studied.the excellent catalytic performance of F/G-PANI@Pt electrode can be attributed to its special 3D structure and the synergistic effect between PANI and Pt nanomaterials.