Effect Of Mo Tuning On The Formation Ability And Electrocatalytic Property Of Fe Based Amorphous Alloy

Because of its unique structure and excellent catalytic performance,amorphous alloys as catalytic electrodes for electrolytic water have attracted extensive attention in recent years.The key to realize the commercialization of electrolytic water tech-nology is to develop efficient and low-cost catalysts for hydrogen evolution（HER）and oxygen evolution（OER）.Nowadays,noble metal elements,such as platinum,palladium,rubidium and indium,are the best catalytic electrodes for electrocatalytic water decomposition.However,due to the rarity and high cost of noble metals,their application in practical production is severely limited.Transition-based amorphous alloys（Fe,Co,Ni,Mo,etc.）have been found to have high catalytic activity in recent years.Some amorphous alloys have been used in electrolytic water decomposition experiments and excellent catalytic effects have been obtained.Based on the amorphous alloys Fe_80-xMo_xP₁₃C₇（x=0,2,4,6,8,10,20,40）and Fe₄₀Co_40-xMo_xP₁₃C₇（x=0,3,5,7,9）,the effects of the composition of amorphous alloys on the amorphous forming ability and the electrochemical hydrogen evolution and oxygen evolution properties were systematically studied.XRD and DSC were token to characterize the two systems and found that both systems were amorphous alloys.With the increase of Mo atom content,the amorphous forming ability of the alloys increased first and then decreased.In Fe-Mo-P-C system,Fe₇₂Mo₈P₁₃C₇ pos-sessed the best amorphous forming ability,and in Fe-Co-Mo-P-C system,Fe₄₀Co₃₅Mo₅P₁₃C₇had the best amorphous forming ability.The good amorphous forming ability indicates that the addition of appropriate Mo atoms increases the dif-ference of atoms and forms the random structure of more dense reactor,thus enhanc-ing the forming ability of amorphous alloys.In addition,the electrochemical proper-ties of the two amorphous systems were tested by three-electrode system.The results showed that the catalytic activity of Fe_80-xMo_xP₁₃C₇（x=0,2,4,6,8,10,20,40）in 0.5M H₂SO₄ acidic solution increased first and then decreased.Among them,Fe₇₄Mo₆P₁₃C₇（x=6）had the best hydrogen evolution activity in electrolytic water.Its hydrogen evolution overpotential was 129 m V and Tafel slope was 51 m V dec^-1.Fe₇₂Mo₈P₁₃C₇（x=8）showed the best catalytic activity for oxygen evolution in 1 M KOH alkaline electrolyte.The initial potential of oxygen evolution was 1.59 V,and the overpotential was 410 m V when the current density was 10 m A cm^-2.In addition,Fe₄₀Co₃₅Mo₅P₁₃C₇（x=5）amorphous alloy has the best catalytic activity in acidic solu-tion and alkaline solution.The overpotential of hydrogen evolution in acidic solution is 90 m V and that of oxygen evolution in alkaline solution is 335 m V.The stability of the two systems decreases with the increase of Mo content.It is found that the formation ability of amorphous alloys is related to the elec-trocatalytic performance.This may be due to the formation of a more stable and ho-mogeneous amorphous structure in the samples with strong amorphous formation ability at the same cooling rate,which can provide more active sites on the surface of amorphous catalytic electrodes,and the synergistic effect between structure and atoms improves catalytic properties of alloys.