Preparation And Electrocatalytic Oxygen Evolution Performance Research Of Two-dimensional NiCo-MOFs Materials

Traditional fossil energy,with its huge and rapid consumption,arouses concerns about energy crises,environmental pollution and so on.Therefore,green and alternative energy sources are in dire need nowadays.Hydrogen energy is pollution-free,has high energy density and is easily available.Hydrogen energy produced by electrocatalytic hydrolysis instead of traditional fossil energy has been widely studied.The anodic oxygen evolution reaction in electrocatalytic hydrolysis requires four electrons to provide power,resulting in slow kinetics and low reaction efficiency due to high activation energy.In view of this,it is necessary to find out economical and efficient catalysts to improve reaction efficiency.Based on the metal-organic framework（MOFs）material,more metal sites,large specific surface area and organized pore structure,two-dimensional bimetallic MOFs were synthesized by electrochemical method as catalysts to make the electrocatalytic OER reaction more efficient in this paper.The main research contents are as follows:1.We used mild electrochemical methods to explore the conditions for the synthesis of Ni-BPDC MOFs.After the best synthetic conditions were determined,with the introduction of different dosing quantity of Co²⁺synthetic NiCo-BPDC MOFs.Then,the structure,morphology and element composition were characterized and the electrocatalytic OER performance of NiCo-BPDC was tested in 1M KOH solution.The study results show that NiCo-BPDC synthesized with different Co²⁺dosages were better than single metal Ni-BPDC,NiCo-BPDC synthesized with 40μmol Co²⁺dosage had the best performance.At 10 m A cm^-2 current density,the overpotential was only 336 m V,and the Tafel slope was only 89 m V/dec,the performance was better than commercial Ir O₂ electrocatalyst.The chief reason is that the ultra-thin two-dimensional structure and bimetallic coordination of NiCo-BPDC provide a larger electrochemical active surface area for electrocatalytic OER reaction.Among them,the ultra-thin two-dimensional structure is conducive to material transport.The bimetallic coordination exposes more metal active sites and accelerates the electrocatalytic OER reaction.2.To improve the catalytic activity and conductivity of two-dimensional MOFs,2,3,6,7,10,11-hexahydroxytribenzene（HHTP）,an organic ligand with conductivity,was used to synthesize two-dimensional CAT MOFs with Ni and Co,which were used for electrocatalytic OER reaction.Ni-CAT and different Co²⁺dosages of NiCo-CAT materials were synthesized by a simple and efficient electrochemical method,tested structure and morphology and electrocatalytic OER performance.When the dosage of Co²⁺was 70μmol,NiCo-CAT had the best electrocatalytic OER performance,the overpotential was only 307 m V,and the Tafel slope was only 61.03 m V/dec at the current density of 10 m A cm^-2,which was higher than NiCo-BPDC.Base on above characterization and test results,we can sure that the NiCo-CAT material has a larger electrochemically active surface area and more conducive to charge transmission,effectively reducing the reaction energy barrier,further accelerates the reaction,and thus improves the electrocatalytic OER performance.