Microstructure And Electrocatalytic Performance Of FeCoNi-based High Entropy Alloy Thin Film Electrode

The high entropy alloy has good corrosion resistance and is expected to be used as a new electrode material in the field of energy and environment.In order to obtain electrode materials with high catalytic activity and no precious metals,FeCoNi based high entropy alloy thin film electrode was prepared by magnetron sputtering method.The microstructure and electrocatalytic performance of the electrode were investigated by means of scanning electron microscope,X-ray diffractometer,electrochemical workstation and other test and characterization instruments.The electrocatalytic for oxygen evolution performance of FeCoNiMoCr high entropy alloy thin film electrode was studied.The results show that the thickness of the film is about 2.40?m and the structure is amorphous.The overpotential of the electrode at 10 mA/cm2 current density is 360 mV and the Tafel slope is 73.5 mV/dec,which shows that the electrode has a good performance of electrocatalytic oxygen evolution.The electrode can be operated for more than 24 h under the overpotential of 360 mV,and has good stability.The effect of sputtering power on the microstructure and electrocatalytic oxidation of organic wastewater by FeCoNiMn high entropy alloy thin film electrode was studied.The degradation mechanism of RhB and the failure mechanism of electrode were analyzed.The results show that the electrode prepared by the DC power supply has higher mixing entropy,stronger direct oxidation capacity and better electrocatalytic oxidation performance than the electrode prepared by the RF power supply.The degradation rate of 10 mg/L RhB solution reached 100%after 270 min.Degradation of RhB is the result of both direct oxidation and indirect oxidation.Compared with the titanium substrate,the lifetime of electrode with FeCoNiMn high entropy alloy thin film is increased from 1 h to 18 h.In the process of electrocatalytic oxidation,the film will corrode and dissolve,resulting in electrode failure.The effects of preparation parameters on the microstructure and electrocatalytic performance of FeCoNiMn high entropy alloy thin film electrode were studied.The results show that the mixing entropy of the electrode prepared at the sputtering power of 50 W is higher than that of the electrode prepared at 30 W and 40 W,and the electrode has the best electrocatalytic performance.The mixing entropy of the electrode prepared with the bias voltage of-40 V and-80 V is the same,but the electrocatalytic performance of the electrode prepared with the bias voltage of-40 V is better because of the larger electrochemical active area of the electrode.With the sputtering time extended from 1 h to 5 h,the electrochemical active area and mixing entropy of the electrode increased,and the performance of electrocatalytic oxygen evolution improved.The electrode of sputtering for 3 h is compact and the performance of electrocatalytic oxidation of organic wastewater is the best.