Preparation Of Micro-nano Ni-Co Alloy Decorated On Porous Electrode And Its Electrocatalytic Activity For Hydrogen Evolution Reaction

Hydrogen is widely used due to its cleanliness and regenerability with many outstanding advantages such as wide source and easy storage.Among mature hydrogen production technology,hydrogen production from water splitting is considered to be one of the most promising technology.At present,hydrogen evolution catalytic materials have the disadvantages of low catalytic efficiency and high hydrogen evolution overpotential.Therefore,in order to reduce energy consumption,it is urgent to explore cathode materials with high catalytic activity and good stability.Improving the catalytic performance of hydrogen evolution materials is mainly based on energy factor and microstructure.Nickel-based alloys have the advantages of good stability and wide range of sources.Among them,Ni-Co alloys have gain important considerations in hydrogen production because of their suitable hydrogen adsorption energy.The porous electrode has the advantage of a large specific surface area,and the decoration of the micro/nano material thereon can further increase the catalytic activity of the electrodes.In this paper,micro/nano Ni-Co alloys were fabricated on a porous electrode by electrodeposition.The samples were characterized by SEM,TEM,XRD,XPS,etc.,and the catalytic performance and stability of different samples in 1M KOH solution were studied and compared.The main research contents and progress are as follows:1.Porous Ni and porous Co were prepared by hydrogen template method.The effects of electrodeposition current density,electrodeposition time and NH₄⁺concentration on the pore density and pore size of porous electrodes were discussed.The optimum process parameters were 2 mol/L NH₄Cl,250 A/dm² current density and 60 s deposition time.2.The porous Ni was used as the substrate to investigate the effects of different process parameters and Ni²⁺/Co²⁺ratio on the growth of Ni-Co alloy and the catalytic performance of the electrode under different morphologies was discussed.The results show that the nanocone Ni-Co/porous Ni composite electrode obtained under 5 A/dm² has the superior catalytic hydrogen evolution performance.The overpotential at a current density of 10 mA/cm² is only-102.1 mV.When the ratio of Ni²⁺/Co²⁺in the plating solution is 4,the nanocone Ni-Co alloys exhibit outstanding activity,only requiring an overpotential of-153.5 mV at 10mA/cm².3.The porous Co was utilized as the substrate to investigate the effects of different process parameters and Ni²⁺/Co²⁺ratio on the growth of Ni-Co alloy and the catalytic performance of the electrodes under different morphologies was studied.The results show that at a benchmark current density of 10 mA/cm²,an overpotential of-109 mV is needed for the flaky Ni-Co/porous Co composite electrode obtained under 10 A/dm².When the ratio of Ni²⁺/Co²⁺in the plating solution is 4,the overpotential for the flaky Ni-Co/porous Co composite electrode is as low as-94.3 mV,for the cathodic current densities of 10 mA/cm².