Nickel-based Selenide Regulated By Iron And Its Application In Oxygen Evolution Reaction

Hydrogen energy has become the first choice of new energy because of the advantages of recycling,clean,low cost and high energy density and so on.Among the new energy equipment,production of hydrogen cannot separate from electrolytic water equipment.But because of its slow anodic reaction kinetics,catalyst is needed to catalyze the reaction.The traditional catalysts for water oxidation are Ru,Ir and their oxides,which are expensive and limit the industrial application of electrolytic water equipment.Therefore,it is urgent for researchers to develop some low price,environmentally friendly and highly efficient non-precious metals catalysts for oxygen evolution reaction.Large number of research data shows that the transition metal selenide has a good oxygen evolution performance and the structure is easy to regulate.Therefore,researchers have done a lot of research on the modification of transition metal selenides to further improve the catalytic perform ance of water oxidation.In this work,the morphology and electronic structure of nickel-based selenides are regulated.The main contents are as follows:?1?The NiSe nanowire was transformed into Ni_x Fe₁-_x Se@Ni?Fe?OOH core-shell structure with the core of ultrafine nanowire and the shell of nanosheet in 30 s by ion exchange reaction.The core-shell structure is not only beneficial to electron transfer and mass transfer,but also increased the specific surface area of the catalyst,which would expose more active sites.On the other hand,many studies have shown that in the process of OER,hydroxyl oxide is the essential catalyst to improve the activity of OER and Fe-doped NiOOH can further improve the catalytic performance.Therefore,the intrinsic activity of the catalyst is improved after modification.This synergetic effect between Ni and Fe significantly reduces the overpotential of the OER reaction.This study provides a method for rapid and simultaneous regulation of the morphology and electronic structure of catalysts,which promotes the research progress of OER catalysts.?2?In order to explore the mechanism of controlling nickel-based selenides by Fe elements.We synthetized NiFe LDH with a various of ratio,and it was converted to Fe-doped NiSe₂ by one-step hydrothermal method.According to the study of morphology,the nano-microsphere transformed into another nano-microsphere with large number of porous after the doping of Fe,which increased the number of the active sites.Besides,the doping of Fe can adjust the average valence state of Ni elements in NiOOH and improve the OER catalytic activity of Ni cation from the analyzing of electron structure by X-ray photoelectron spectroscopy.In addition,the electrochemical impedance spectroscopy shows that the doping of Fe can improve the conductivity of NiSe_2.The results can further prove that the doping of the Fe element can promote the oxygen evolution reaction of the nickel-based selenide.The study deepens the researchers'understanding of the synergistic effect of Ni and Fe.