Study On Modification And Electrochemical Performance Of NiCo Double Hydroxides Self-supporting Electrode

In recent years,the excessive exploitation and application of traditional fossil fuels have caused a series of environmental problems.Therefore,it is considered to replace them with high energy density and sustainable hydrogen.In order to obtain high-purity hydrogen,an electrochemical method is usually used to prepare hydrogen.Among the HER electrocatalysts,low-cost transition metal compounds have been considered as potential substitutes（such as oxides and hydroxides）to noble metal-based materials.However,the Volmer processes related to HER under alkaline conditions are severely hindered,and the OER of the anode is synchronized during water splitting.Therefore,the material needs to be optimized to reduce the overpotential under high current density.This article modifies and regulates transition metal hydroxides through the regulation of copper ions,doping of carbonized polymer dots and vulcanization of thiourea.（1）An efficient Cu-decorated Ni Co dihydroxy nanoflower catalyst（NiCoCu-OH/NF）was prepared by a simple one-step hydrothermal method.Copper ions reacted with the NF substrate to generate copper intermediate ions,thereby promoting the formation of Ni³⁺.This provided an effective charging channel for fast electronic transmission and further improved internal activities.In 1M KOH,the nano-flower-like catalyst Ni₂Co Cu_0.8-OH/NF only needs extremely low overpotentials of 19 m V and 152 m V to reach 10 m A cm^-2 and 100 m A cm^-2,respectively.For the oxygen release reaction,the Ni₂Co Cu_0.8-OH/NF material can achieve a current density of 10 m A cm^-2 at an overpotential of 310 m V.For the water splitting reaction,it can reach a battery voltage of 1.59 V.When using Ni₂Co Cu_0.8-OH/NF as cathode and anode for hydrogen evolution and methanol oxidation reaction dual function electrode test,it was found that merely an ultra-low cell voltage of 1.47 V can reach 10 m A cm^-2 current density.（2）The o-phenanthroline containing different functional groups and the transition metal salt were complexed to prepare solution under water bath heating at 60°C.Afterwards,under hydrothermal conditions,the carbonized polymer dots and Ni Co double hydroxyl nanorods were combined on the surface of the Nickel foamed substrate to form an efficient carbonized polymer dots-transition metal double hydroxyl catalyst（CPDs/NF-Co Ni）.The interwoven network NCo Cu-5 CPDs/NF-Co Ni catalyst has excellent HER performance and exhibits a low overpotential of 65 m V at 10 m A cm^-2,and a new Co-N electron transmission channel was created in the composite material,thus creating a suitable electronic environment between Co and NCo Cu-5 CPDs.The appearance of Cu²⁺ions further promoted the formation of high-valence Co³⁺,thereby increasing active sites and reducing the reaction overpotential effectively.（3）The metal dihydroxy electrode material prepared by doping transition metal copper ions was vulcanized with thiourea,and the non-metallic controlled Ni₂Co Cu-S-OH/NF composite material was successfully synthesized.In 1.0 M KOH,the OER and MOR performance of the Ni₂Co Cu-S-OH/NF（B）before and after sulfation under acidic condition were studied under the three-electrode system.It was found that the OER activity of the material was significantly improved.When the current density was 100 m A cm^-2,compared the electrode material before vulcanization,the overpotential was decreased by 142 m V;after methanol was added to the 1.0 M KOH,the overpotential further decreased.