Study On Oxygen Evolution Reaction Activity Of Electrocatalysts Via Laser Surface Fabrication

The rapid development of modern society depends on the consumption of large amount of fossil fuels.However,fossil fuels are non-renewable source with high pollution and carbon emissions,where a clean and renewable alternative is urgently needed.Hydrogen is an ideal choice as a high-efficiency,green,and sustainable energy.Among the many ways of hydrogen production,water electrolysis stands out because of the renewable raw materials,zero-pollution,and no carbon emission,however,the actual potential applied for water electrolysis is generally much higher than the theoretic value,resulting in a large energy consumption and the increase of the production costs.To reduce the high energy barriers of the two half reactions and replace the state-of-art expensive noble-metal-based catalysts,especially for oxygen evolution reaction,the preparation of low-cost electrocatalysts with high catalytic activity and good long-term durability has been a hot topic of the current research.At present,most of electrocatalysts are fabricated by chemical methods,which is generally time-and energy-consuming with complicated process and extra pollutants.To tackle these,a simple strategy is developed via femtosecond laser ablation on metal surface to fabricate metal oxides based electrocatalyst for oxygen evolution reaction in the present work,which is fast,facile,and environment-friendly.The obtained electrocatalysts demonstrated excellent oxygen evolution reaction activity and good long-term stability.The main contents of the thesis are as following:（1）By dropping the precursors of Fe Cl₃solution uniformly on the surface of nickel foam and followed by vacuum drying,we successfully incorporated Fe into the nickel foam surface via femtosecond laser ablation to obtain Ni Fe oxides with rich micro/nano-structures.The Ni/Fe ratio can be readily tuned by the amount of Fe Cl₃precursor.The fabricated Ni Fe oxides demonstrated excellent OER activity and good stability,due to the strong electronic synergistic effect between Ni and Fe,with a low overpotential of 221 m V at 25 m A/cm².（2）To resolve the low conductivity of metal oxides,we fabricated the conducting polyaniline and then dropped it on the surface of laser-ablated nickel foam to obtain Ni O/polyaniline composites.Electrochemical impedance spectroscopy showed that the transfer resistance decreased significantly with the incorporation of polyaniline.Because of these,the obtained Ni O/polyaniline composites showed a clear enhancement of the OER activity,with a decline of overpotential from 368 m V to 301 m V at 10 m A/cm².The long-term durability test indicates a good stability of the electrocatalysts.In summary,the present work developed a simple surface modification strategy via laser ablation to fabricate metal oxides micro/nano-structures for oxygen evolution reaction,which is simple,facile,and environment-friendly.The present work sheds light on the preparation of OER electrocatalyst with high efficiency and good long-term durability.