Synthesis Of Transition Metals Nanocatalyst For Active Oxygen Evolution Catalysis

Environmental problems have become increasingly serious due to accelerated consumption of traditional energy sources.Hydrogen is regarded as an ideal energy carrier for storage and supply because of its advantages of high calorific value,clean and pollution-free,Which has attracted much attention.The hydrogen produced by water electrolysis,which makes full use of non-grid-green energy such as solar energy and wind energy,is an important method for producing high-purity hydrogen.However,the oxygen evolution reaction on the anode involving a multi-proton coupling electron transfer process,which leads to a slow kinetics of the semi-reaction during water splitting,becomes a bottleneck for hydrogen production technology.Thus,the pursuit of efficient electrocatalysts with excellent OER activity has become a key of the development of hydrogen production technology in the current.A large number of studies have shown that nickel?iron?-based and cobalt?iron?-based catalysts,with low cost and outstanding OER activity,have attracted widespread attention.The phosphides/borides are mostly used as electrocatalysts with excellent hydrogen evolution reaction activity,while few samples are used as oxygen evolution reaction electrocatalysts.However,the activity of the oxygen evolution catalyst is not better than noble-metal-based materials.Generally,The OER performance can be improved by element doping and the modulated electronic structure.It can be seen that the phosphides/borides have a great potential.In this paper,two strategies are used to dope non-metallic,and XRD,SEM,TEM,XPS and other characteristics and a series of electrochemical performance tests are used to find the optimal conditions.Then the relationship between the structure and OER activity are discussed.The specific content is mainly divided into four aspects as follows:?1?A series of amorphous Ni FeB nanoparticles,with varying atomic ratios of Fe,are synthesised by a chemical reduction method,and used as the OER catalyst.The amorphous NiFeB(?_Fe=0.20)nanoparticles have the best performance,and display highly active electrocatalytic performance for the OER in a broad range of pH values.It is found that borate-enriched NiFe OOH layer was formed in situ on the surface of the catalyst by structural characterization.Through its structural characterization,The amorphous NiFeOOH layer,intrinsic amorphous nanostructure and Fe doping,which all contribute to the best catalytic activity of NiFeB(?_Fe=0.20).In 1 M KOH solution,the catalyst showed a relatively low overpotential of 251 mV on glassy carbon,with a Tafel slope of 43 mV/dec.?2?The ultra-fine amorphous CoFeB nanomaterials with different Fe contents are fabricated by the same method.The CoFeB(?_Fe=0.3)nanocatalyst can exhibit high-efficiency OER activity in the pH range of 14⁷,and OER performances improved as the pH value increased.The nanocatalyst shows the best OER activity and stability in 1M KOH solution.?3?Ni₂P nanocatalyst is prepared by a safe and simple sol-gel method.The OER activity was enhanced by Fe doping and electrochemical activation.It is found that a thin,small-sized nanosheet layer was formed in situ on the Fe-doped Ni₂P catalyst surface during electrochemical activation,and its performance was significantly improved.?4?Fe-doped Co₂P nanocatalysts are fabricated by the same method and the Fe doping improve the OER activity of the Co₂P nanocatalysts,which exhibite excellent OER activity and stability.In 1 M KOH solution,the overpotential is289 mV at 10 mA/cm²,and the Tafel slope is only 40 mV/dec.