Study Of Peparation Of High-efficiency NiCu Three-Dimensional Electrodes By Surface Electrochemical Reconfiguration And Its Electricity Performance

As a clean energy carrier,hydrogen is expected to replace the increasingly depleted fossil fuels.However,there has been a problem of transporting and storing hydrogen due to its low bulk density.To improve this problem,hydrogen can be stored in indirect hydrogen storage media,such as ammonia,methane,and methanol.Among them,ammonia is a hydrogen-rich carrier with 17.6 wt.%hydrogen content,which is an ideal carbon-free fuel,however,ammonia fuel cells have been suffering from membrane problems that hinder their development.The construction of Flow-through NiCuthree-dimensional（3D）flow-through porous anode can improve the boundary layer problem of fuel concentration and slow kinetics of ammonia oxidation caused by Flow-over type planar anode,thus improve the cell efficiency.The main studies are as follows:（1）Using a simple ultrasonic method,Cuwas added to the nickel foam skeleton as a dopant,and NiCuprecatalysts encapsulated on nickel foam electrodes were prepared by the GRR reaction between nickel foam and Cu²⁺.After activation under alkaline conditions,the NiCuprecatalytic electrodes were heavily reconstituted to form petal-like CuCl/Nimixed metal hydroxides,which proved to be"true"AOR catalyst.This structure allows for rapid ion diffusion and provides an abundance of active sites.In addition,the three-dimensional flow of the porous anode facilitates ion diffusion,enriching the active sites and solving the problem of slow ammonia oxidation kinetics.The results of CV tests show that the CuCl/Nistructured3D electrode has high activity with a maximum current density of 97.8 mA cm^-2at 0.6 V at 20min of sonication,and good stability in i-t curve test.（2）NiCu@NiCuOOH-NF core-shell structure 3D electrode was obtained by electrodeposition and surface reconstruction by electrooxidation,and the core-shell structure3D electrode was confirmed by SEM,TEM,XRD and XPS with NiCuas the core and NiCuOOH as the shell as the"true catalyst".In this structure,the metal core promotes charge transfer to the surface hydroxide,and the 3D structure promotes rapid fuel diffusion,which solves the fuel concentration boundary layer problem,provides abundant active sites,and significantly improves the slow kinetics of ammonia oxidation.The results from CV tests show that the NiCu@NiCuOOH-NF core-shell structured 3D electrode reaches a maximum current density of 90 mA cm^-2with high activity at 0.65 V vs.SCE.A high specific surface area of 65.75 cm²was obtained based on the LSV test results and the i-t curve test showed good stability.（3）The prepared 3D nanoelectrodes were used as the anodes of Flow-through DAMFC,and the DAMFC was fueled with 2 M NaOH+3 M NH₄Cl as the fuel electrolyte,and an OCV of 0.92 V was obtained with peak power density and maximum current density of 17.1 mWcm^-2and 102 mA cm^-2,respectively.the fuel depletion boundary layer problem of conventional DAMFC was greatly improved,showing good performance.The fuel depletion boundary layer problem of conventional DAMFC is greatly improved and shows good cell performance.This work provides a new preparation strategy for practical non-precious metal nanomaterial-based AOR electrodes and promotes the development of DAMFC.