Investigation Of Micro/Nanostructure Preparation By Femtosecond Laser And Their Electrocatalytic Properties For Hydrogen Production

Electrocatalytic water splitting hydrogen production is one of the most important hydrogen production methods in industrial hydrogen production.Currently,self-supported electrodes with strong interaction between the catalyst and the substrate,excellent durability,high conductivity,and large electrochemical surface area have become a new trend in research on enhanced hydrogen production performance.At the same time,the process of high-efficiency hydrogen production is not only an electrocatalytic chemical process,but also a kinetic physical process in which hydrogen is separated from the three-phase line of solid,water,and gas on the electrode surface.How to optimize synergistically is the key issue and challenge for the application of catalysts for electrocatalytic hydrogen production.,which also proposes a new development direction for the design and manufacture of catalysts and their microstructures on the electrode surface.This article mainly relies on femtosecond laser micro-nano processing technology to prepare and study the characteristics of micro-nano-structured electrodes for electrocatalytic hydrogen production,with the goal of simultaneously improving the physical and chemical properties of the hydrogen production electrode to enhance hydrogen production performance.The specific research content is as follows:（1）This study utilized femtosecond laser micro-nano processing technology and hydrothermal method to prepare Mo S₂micro-nano structured self-supported electrodes,and their hydrogen production performance was investigated.The results showed that the Mo S₂/fs-Mo electrode prepared in alkaline environment only required an ultra-low overpotential of 99 m V to achieve a current density of 10 m A·cm^-2.Compared with the polished surface,the overpotential of the micro-nano structured electrode was reduced by more than 300%.Our analysis reveals that the excellent hydrogen evolution performance of the electrode is attributed to two factors.On the one hand,the micro/nano-structures prepared by femtosecond laser technology not only achieve the dual-scale structure of the final product,enhance the wettability,but also increase the specific surface area,thereby increasing the number of active sites and promoting the hydrogen evolution reaction.On the other hand,femtosecond laser technology has the ability to process and synthesize oxides in air,which can further promote the hydrogen evolution reaction based on the coordination effect of oxide ions.（2）This study employed femtosecond laser direct-writing technology to one-step prepare self-supported Ni O/Ni electrodes,and the effect of femtosecond laser scanning distance on the hydrogen production performance of the electrode was investigated.The results showed that changing the femtosecond laser scanning distance can alter the specific surface area of the electrode,affect the wetting characteristics,and adjust the degree of electrode oxidation.Based on femtosecond laser micro-nano processing technology,a Ni O/Ni electrode was screened out,and only an ultra-low overpotential of 57 mV is required to achieve a current density of 10 m A cm^-2in an alkaline environment.Furthermore,the one-step preparation and oxidation of the electrode construction method provides stronger mechanical stability and chemical homogeneity due to its simple process,enabling the electrode to maintain excellent stability in hydrogen evolution performance for 144 hours of operation.Through the analysis of bubble dynamics,it is found that the micro-nano structure brought more active sites to the electrode and has the ability to reduce the size of hydrogen bubbles,making hydrogen evolution efficient and stable.In addition,changing the femtosecond laser scanning distance can further control the number of active sites and the size of hydrogen bubbles detachment.The combination of femtosecond laser micromachining（micromachining of substrates for nanostructure construction）and hydrothermal synthesis(（growth of nanoparticle catalysts on microstructured surfaces）can create a dual-scale substrate that further enhance wettability and facilitate the detachment of hydrogen gas bubbles.The unique advantages of the one-step femtosecond laser direct writing method make it highly feasible in industrial production conversion.Therefore,the application of femtosecond laser surface modification technology to electrocatalytic hydrogen production shows promising application prospects.