Study On The Performance And Mechanism Of Ternary Transition Metal Phosphide Electrocatalytic Decomposition Of Water For Hydrogen And Oxygen Evolution

In recent years,problems such as environmental pollution and shortage of resources caused by over-combustion of fossil fuels have caused people to attach importance to clean and renewable energy sources.Electrolysis of hydrogen from water is a green way to produce clean energy,which is worthy of people's attention.For electrolysis of water to make hydrogen technology,taking into account the principle of low cost in the actual production,we need to look for low-cost transition metals to replace precious metals for the study of electrocatalysts.According to previous reports,transition metal phosphides have a special energy band structure,exhibit good electrocatalytic activity and electrochemical stability in the study,However,binary phosphides have a limited crystal structure and poor performance adjustability.Studies have shown that there is a general synergistic effect between the constituent elements of the material.Accordingly,the construction of a ternary transition metal phosphide will be an effective way to improve the electrocatalytic performance of the material.In this study,binary phosphides with the same crystal structure were selected to construct a ternary system.The main research objects were Ni-Fe-P and Co-Fe-P electrocatalyst materials.The main research contents are as follows:?1?Ni_1.5Fe_0.5P_x electrocatalysts were constructed on carbon fiber felt?CF?and nickel foam?NF?by hydrothermal method and low-temperature phosphating method respectively and their electrolyzed water properties were investigated under alkaline conditions.The three-electrode system shows that the electrocatalytic hydrogen evolution and oxygen evolution activity of Ni_1.5Fe_0.5P_x is much higher than that of NiFe-LDH precursor,while the NF-based catalyst array has better electrocatalytic activity than CF-based catalyst array.The former benefit from Ni_1.5Fe_0.5P_x good intrinsic conductivity,which is conducive to the electrons in the catalyst material;the latter benefit from the close contact between the catalyst and NF,which is conducive to the transmission of electrons from the substrate to the surface.Through the study of two-electrode system,it was found that Ni_1.5Fe_0.5P_x@NF exhibited the best electrocatalytic performance in the full hydrolysis test and the voltage required to generate a current density of 10 mA?cm^-2 was only 1.55 V,which was obviously better than Industrial Pt@Ti||RuO₂/IrO₂@Ti electrode pairs?1.62 V?.?2?Co_xFe_1-xP@CC nanowire arrays were constructed on carbon cloth?CC?by hydrothermal method and low temperature phosphating method and their electrolyzed water properties were investigated under alkaline conditions.In the three-electrode test system,the electrocatalytic activity of Co_xFe_1-xP@CC was systematically explored by normalized surface area,catalyst mass,and electrochemical surface area.It was found that when the ratio of Co to Fe was 1:1.The hydrogen evolution activity was the best when it was nearby(Co_0.56Fe_0.44P@CC),while the oxygen evolution activity was the best when it was 3:1(Co_0.79Fe_0.21P@CC).In the two-electrode test system,the cocatalyst three-way catalyst system of Co and Fe exhibited a remarkable synergistic effect,in which the Co_0.79Fe_0.21P@CC nano-array exhibited the best performance at a current density of 10 mA?cm^-2.The voltage required is only 1.60 V.