| The massive use of fossil fuels has led to huge carbon emissions,and the concentration of carbon dioxide in the atmosphere is increasing year by year,aggravating global warming and making energy and environmental problems more and more serious.Hydrogen（H2）is a clean energy that can realize decarbonization in the process of energy utilization.It has the advantages of high energy density and zero carbon emission.Under the background of carbon peaking and carbon neutralization,it is considered to be the ultimate energy to solve energy and environmental problems.Using renewable energy to produce hydrogen by electrolysis of water is a feasible way,but the current cost of hydrogen production by electrolysis of water is high,and it is difficult to apply it on a large scale.,Low-cost electrolysis of water hydrogen evolution catalyst is the top priority.Currently,the most efficient electrocatalysts are noble metal-based catalysts such as platinum,palladium,iridium,or ruthenium,and it is very important to find inexpensive,high-performance,and long-life alternative materials.Transition metal phosphides（TMPs）have unique physical and chemical properties and rich reserves.They are a promising substitute for noble metal catalysts and have excellent electrochemical hydrogen evolution reaction（HER）performance.This work is committed to developing new and low-cost transition metal phosphide hydrogen evolution catalysts.By reducing the amount of precious metals,constructing heterostructures,optimizing the surface morphology of catalysts and synthesizing self-supporting electrocatalysts,three kinds of high-performance electrocatalytic hydrogen evolution catalysts have been developed,and their hydrogen evolution performance and mechanism have been studied.The specific work contents are as follows:（1）Co2P was grown on nickel foam（NF）by a facile hydrothermal method and vapor-phase phosphating method,and Co Pt was deposited on Co2P using electrochemical cyclic voltammetry（CV）scanning for electrochemical platinum sensitization.The deposition of Co Pt greatly enhances the HER performance of Co2P.The electrochemically active specific surface area（ECSA）and intrinsic catalytic activity were both improved,and the electrocatalytic hydrogen evolution activity was greatly improved.Electrochemical test results show that Pt-Co2P/NF has extremely high electrocatalytic activity in alkaline electrolyte,with overpotentials of only 13 m V and133 m V at 10 m A·cm-2 and 1000 m A·cm-2,respectively.Especially at high current density,the Pt-Co2P/NF catalyst exhibits excellent catalytic activity and stability,which is closer to the requirements of the hydrogen production industry.Through a series of experimental characterization methods,combined with first-principles calculations based on density functional theory（DFT）,a mechanism of chemical transformation is proposed to explain the platinum-sensitized behavior exhibited by the material in HER.（2）A self supporting phosphating ZIF-67 electrocatalyst with stable growth on the foam copper skeleton was constructed by using ZIF-67 as the precursor.The problem that ZIF-67 precursors were difficult to adhere to the foam copper substrate was overcome.In the indirect way of ZIF-67 growth,a fine needle like copper hydroxide substrate was first grown in situ on the foam copper skeleton as the attachment site of ZIF-67 nanoparticles,and the ZIF-67 was uniformly and densely adhered to the foam copper skeleton successfully.Then the P-ZIF/Cu2O/Cu heterostructure electrocatalyst was obtained by gas-phase phosphating.It showed excellent electrocatalytic hydrogen evolution performance in 1M KOH solution.When the cathode current density was 10m A cm-2.,the overpotential was only 62 m V,especially the excellent performance of the electrocatalyst under high current density.The current density of 1000 m A·cm-2 could be achieved by 358 m V overpotential.（3）Mo2S precursor was grown on foamed copper substrate,the morphology of the catalyst attached to the electrode surface was adjusted by Co doping,and a self-supporting electrocatalytic hydrogen evolution electrode was synthesized by gas-phase phosphating method.Through electrochemical tests and scanning electron microscopy,the results show that the addition of Co can effectively improve the surface morphology of the Mo P/Mo S2/Cu electrode,increase the specific surface area of the electrode,improve the degree of amorphization of the catalyst,and improve the intrinsic activity of the catalyst.The catalyst supported on the surface of Co-Mo P/Mo S2/Cu electrode is spherical,with dense thorn-like protrusions,large specific surface area,and amorphous morphology.When the current density is 10 m A·cm-2,the overpotential is 60 m V,which has good electrocatalytic hydrogen evolution activity and good stability at high current density,which can better meet the requirements of industrialization.In this work,three different precursors were constructed by a simple hydrothermal,room temperature liquid phase reaction,and transition metal phosphides were obtained by gas phase phosphorylation.The material performance is enhanced by elemental doping,construction of heterostructures and electrochemical sensitization,which shows excellent electrocatalytic hydrogen precipitation performance in alkaline media and maintains good catalytic activity and stability under high current density,with potential for industrial applications. |
