Study On Preparation Of Co And Fe-based Compounds And The Performance Of Electrocatalysis

The development of clean and sustainable energy is imminent.Because of its pollution-free and high energy density,hydrogen is considered to be one of the most promising energy carriers to meet the needs of sustainable development.Compared with traditional hydrogen production methods,electrochemical water splitting has the characteristics of mild preparation conditions,high efficiency,and environmental friendliness.It consists of cathode hydrogen evolution reaction（HER）and anode oxygen evolution reaction（OER）.However,the lack of efficient,durable and economical electrodes to promote HER and OER has greatly hindered the development of water splitting technology.Therefore,the development of HER and OER electrocatalysts with excellent durability,high efficiency and low cost is still the key to solving the problem.Transition metal selenides,boron-containing compounds,and phosphides have good HER and OER catalytic activity under alkaline conditions,especially the use of simple and gentle methods to prepare materials has become a current hot spot.The work of this thesis is based on foamed nickel,by solvothermal method,liquid deposition method,electrodeposition method to synthesize Co,Fe selenide,boron-containing compound,and phosphide,respectively,and the catalytic performance of electrolysis of water under alkaline conditions.（1）Through the solvothermal method,FeSe-NF and CoSe-NF were prepared on nickel foam substrate.FeSe-NF has a dendritic three-dimensional structure with a large surface area.In HER,when j=-10 mA·cm^-2,η=-168 mV;In OER,when j=100 mA·cm^-2,η=319 mV.By adjusting the composite ratio of molybdenum and sulfur,the Co_0.7Mo_0.3Se_0.5S_0.5-NF electrode material with better hydrogen evolution performance was obtained.when j=-10 mA·cm^-2,η=-127 mV,when j=-100m A·cm^-2,η=-255 mV.After working for 20 hours at a current density of-20 mA·cm^-2,there is almost no change in potential.（2）A liquid phase deposition method was used to prepare amorphous Co_0.7Mo_0.3B_x-NF and Co_0.9Fe_0.1B_x-NF electrode materials on the nickel foam substrate.Among them,Co_0.7Mo_0.3B_x-NF has good HER catalytic performance.When j=10 mA·cm^-2,η=-112 mV;Co_0.9Fe_0.1B_x-NF has good OER catalytic performance,when j=50 mA·cm^-2,η=315 mV;The above two materials were operated at current densities of-20 mA·cm^-2 and 50 mA·cm^-2 for 20 h,and the potentials remained stable.（3）Using electrodeposition method,CoP-NF and FeP-NF were prepared on the nickel foam substrate.when the deposition potential is-1.4 V,deposition time is 300 s,and B:P=1:1,CoP-NF has excellent HER catalytic performance,when j=10 mA·cm^-2,η=-70 mV,Under 20 mA·cm^-2,continue the HER reaction for 20 h,and the potential remains stable;when the deposition potential is-1.4 V,the deposition time is 60 s,and B:P=1:1,FeP-NF has excellent OER catalytic performance,when j=50 mA·cm^-2,η=280 mV,working at 50 mA·cm^-2 for 20 hours,the voltage is almost unchanged.